The NewsDepartments Increase

This is the second issue featuring the ClayLinks col­umn by Barbara Coultry. Barbara received a lot of feed­back following the premiere in the Spring 1999 issue, and provides another batch of web sites of interest to readers in this issue. Check out her latest picks on page 6.

Sumi von Dassow has written a feature we re calling “Off the Shelf” Sumi teaches ceramics and uses books in preparing materials or researching a question. She recommends, and even loans, books to her students on a regular basis. Our intent here is to bring you “up to speed” on existing works and provide newcomers to craft with recommendations of books that have with­stood the test of time.

Both Barbara and Sumi welcome feedback and your ideas, so feel free to write or e-mail them.NCECA and the Clayart Room

Pottery Making Illustrated made it to NCECA (Na­tional Council on Education for the Ceramic Arts) in Columbus, Ohio, in March. In addition to having a booth, PMI also sponsored the Clayart Hospitality Room during the conference. Clayart participants used the room as a retreat and meeting place to exchange a variety of ideas and bits of information face-to-face instead of in cyberspace. An added feature was the dis­cussion of kiln coatings by Mel Jacobson and an evening reception held by ITC. Plans are in the works for PMI to sponsor the room again next year in Denver.Teachers and Students

PMI was present at the National Art Education As­sociation conference inWashington,D.C.,in early April. Art teachers from around the country found PMI to be a great resource for the ceramics studio in their school, and provided suggestions worth considering for future issues.

As for the students, we’ve once again showcased high school work from the Ohio Governor’s Youth Art Ex­hibition, but were unable to show more than a handful of the dozens of ceramic entries. We’re interested in covering student exhibitions, so check our web site for details about contributing.5 Issues in 2000

The biggest news for 2000 is that we’re expanding PMI to include a fifth issue. Beginning next July, we’re introducing the special Potters Guide edition, a ceramics resource directory. This new issue of PMI will provide useful information about available products and services and valuable reference materials. The additional infor­mation should prove to be an asset for every studio and artroom. Enjoy!

Pottery Making illustrated 1

Summer 19992

Cover: Indiana Roadside Series (Hardwood Winter): Round jug and cup, to 9 inches in height, stoneware, glazed and unglazed surfaces, wood fired to cone 11, by Dannon Rhudy. See story page 9.

Pottery Making illustrated

ClayLinksby Barbara Coultry ..........................................................................6Our web surfer has picked some great sites of interest and provided reviews

Getting It Togetherby Dannon Rhudy............................................................................. 9Discover a great technique for handbuilding inside thrown forms

The 1999 Ohio Governors Youth Art Exhibition.. 16Ohio high school students exhibit some of their best work

Tobikannaby Brad Sondahl............................................................................. 18Making and using the Japanese “jumping iron”

Throwing Bottom Firstby Donald M.Adamaitis.......................................................... 21Reverse your technique for throwing on the wheel

Textures are Everywhereby Chris Campbell................................................................. 25Create any texture using materials and tools around you

Clay Draw Planeby Ivor Lewis........................................................................ 30Make a tool to cut perfect mitered edges every time

Eye Protection for Pottersby Jeff Zamek........................................................................33Safely protect your eyes in the studio

Measure for Measureby Lili Krakowski.................................................................. 36Mix glazes using cups and spoons

Building a Domed Cylinder Kiln—Part Iby Donald M. Adamaitis......................................................... 40Begin building a durable kiln with fiber and fence

Off the Shelfby Sumi von Dassow.............................................................. 46Take a look at the books recommended by a teacher

Editor: Bill JonesProduction Manager: John Wilson Graphic Design: Debi Hampton Graphic Production: Robin Chukes Advertising Manager: Steve Hecker Advertising Assistant: Renee Fairchild Customer Service: Mary Hopkins Publisher: Mark MecklenborgEditorial, Advertising & Circulation Offices735 Ceramic Place PO Box 6136Westerville, OH 43086-6136 Phone: (614) 794-5890 Fax: (614) 794-5892 E-mail: potterymaking@acers.org Web site: www.potterymaking.orgPottery Making Illustrated (ISSN 1096-830X) is published 5 times a year by The American Ce­ramic Society, 735 Ceramic Place, Westerville, OH 43081. Standard mail (A) postage paid at Westerville, OH.Opinions expressed are those of the contributors and do not necessarily represent those of the edi­tors or The American Ceramic Society. Subscription rates: One year $18, two years $34, three years $49. Add $15 per year for sub­scriptions outside North America. In Canada, add GST (R123994618). All payments in US dollars. Allow 6-8 weeks for delivery. Advertising: Ad rates and ad information are available on the web site or by contacting Steve Hecker at the address above or by phone at (614) 794-5809.Change of address: Send your change of ad­dress via e-mail or to the Circulation Depart­ment. Allow six weeks advance notice. Contributors: Writing and photographic guide­lines are available on request and on the web site. Mail manuscripts and visual materials to the edi­torial offices with a self-addressed postcard for no­tification of receipt.Indexing: Feature articles are indexed in the Art Index and daai (design and applied arts index), avail­able through public and university libraries. Photocopies: Permission to photocopy for per­sonal or internal use beyond the limits of Sec­tions 107 and 108 of the U.S. Copyright Law is granted by The American Ceramic Society, pro­vided that the base fee of US$5 per copy, plus US$0.50 per page, is paid directly to the Copy­right Clearance Center, 222 Rosewood Dr., Danvers, MA 01923 USA (508) 750-8400.This consent does not extend to other kinds of copy­ing, such as copying for general distribution, for advertising or promotional purposes or for cre­ating new collective works. Requests for special photocopying permission and reprint requests should be directed to the Director of Publica­tions, The American Ceramic Society, P.O. Box 6136, Westerville, OH 43086-6136.Back Issues: When available, back issues are $5 each, plus $2 postage. Add $5 for orders outside North America. In Canada, add GST Postmaster: Send address changes to Pottery Making Illustrated, PO Box 6136,Westerville, OH 43086-6136. Form 3579 requested.

Summer 1999

Copyright © 1999 The American Ceramic Society All rights reserved

4

Pottery Making illustrated 5

by Barbara Coultry

Wheels of TimeSince ClayLinks’ debut in the Spring 1999 issue, you’ve

been sending excellent links to claylink@nycap.rr.com. As you do your own surfing, don’t forget to poke around in commercial sites, where you’re just as likely to find those educational or inspirational elements we’re all look­ing for.

The current column started out with the idea of cov­ering potter’s wheel sites exclusively, but as we all know, one thing inevitably leads to another. What follows are practical, technical, beautiful and educational sites.These sites include building your own wheel to throwing a juicer and from pottery making in the present, back through medieval times to biblical days. I think you’ll enjoy visiting them as much as I did finding them.

Bridges for Peace www.bridgesforpeace.com/index.html

A site with Israel as its focus, Bridges for Peace has a collection of articles large enough that you should find at least one you’ll want to read. (I found far more than one.) For instance, “Pot­tery Making in the Bible” will send you back to a time when the potter’s trade was an essential one. You can also read about clothing, metalwork and transportation in biblical days. To find all this and far more, click on “Dispatch,” then “Everyday Life in Bible Times.” Once you’ve read everything here, click on “Ar­chaeology,” where you’ll discover even more ceramics-related articles.

JH Potteryw ww. j h potte r y. co m

John Hester, an elementary school teacher, gives concise lessons on the basics of forming a pot: pinch, coil, pressed coil, slab and potter’s wheel techniques. Knowing you’ll also need something with which to hold the pot, he shows how to make and attach handles. Since Hester plans to add a tutorial on glaze recipes and techniques, bookmark his site so you can return periodi­cally to check for the addition. Also, don’t miss his fine collec­tion of links for wandering hither and thither on the ceramic side of the web.

clayKnk@nycap.r r. com

This is my e-mail address. Please send your favorite sites and discoveries to me at this address. Also, put my e— mail address into your address book.When you find a par­ticularly good site that you think other Pottery Making Illustrated readers might be interested in, send me the link.

What am I looking for? If it has to do with ceramics and has good beginner, intermediate or advanced infor­mation, I want to know about it. Also, since we ceramics artists aren’t inspired only by things made of clay, if you find a nonceramics site that has solid information, ele­ments of inspiration, or contains ideas for new things we might do with clay, by all means share it. Examples might be a page devoted to polymer clay or a gallery of Inuit soapstone carving.

I can’t personally answer everyone’s e-mail—I’m sure you understand—but, believe me, I’ll be checking out each and every link you’re kind enough to send. B.C.

Summer 1999

Marvin Bartelwww.goshen.edu/~marvinpb/MB_Home.htmSome of us are old enough to remember what was called a “governor,” a contraption used to keep drivers (particularly teen­agers) from speeding. Bartel, an art professor at Goshen Col­lege, has an interesting tip reminiscent of those governors for controlling the speed of an electric potters wheel. He’ll tell you all about it if you click “Hints for Potters.” This is also where you’ll find information on loading greenware plates and a tip for cone placement. If you’re a teacher, click on “Art Lesson Pages” for some good ideas.

The Smithswww.dreamscape.com/smiths/plans.html

Are you handy? Short of cash? Would you rather make it than buy it? Go to Randy Smith’s site where you can inspect, then download plans and images for both a kickwheel and a Leach- style treadle wheel. The Adobe Acrobat Reader kickwheel plans are absolutely clear, include all the essential illustrations and should be easy to follow. The pictures for the treadle wheel are also clear and easily sent through your printer. Hats off to Randy Smith for sharing his knowledge and doing it so well.

Barbara Coultry welcomes suggestions and comments from readers about ClayLinks. Please send your favorite sites and discoveries to her at claylink@nycap.rr.com. While she can't respond to each e-mail, she will check every link suggested.

Here are some additional sites I thought you might enjoy taking a look at:Canadian Museum of Civilizationwww.civilization.ca

If I were to describe this site and do it justice, I’d have to write a complete article about it. Don’t miss it, not a single piece of it. Start at the “Site Index,” then click on anything related to pot­tery. After that, click on everything else. I mean it. Everything.Elizabeth Priddy’s Clay Workshop www.angelfire.com/nc/clayworkshop

Priddy shares her ideas in a collection of how-to articles, from throwing a juicer to “Pottery Tips and Techniques” and “Philo­sophical Essays and Thoughts.”Regia Anglopumwww.regia.org/pottery.htm

This is the pottery page of a much larger and fascinating site about Medieval Britain. Imagine yourself in a past with neither electricity nor pottery-supply companies.A.R.T. Studio Clay Companywww.artclay.com/wheel_start.htm

If you’re getting ready to buy, here’s a place where you can study in-depth information on various types of potter’s wheels.Charles Hughes Potterywww.thecreativeoasis.com/hughes.html

Hughes’ student “Handbook,” a 12-page pamphlet in Adobe Acrobat Reader format, makes good reading for all of us. In the end, we’re all eternal students.Hall Chinawww.inter-services.com/HallChina/potterytour.html

Take a tour of a semi-automated pottery where the wheel is still used, though probably not quite like most of us do in our own studios.The Studio Potterwww.studiopotter.org

After reading “Why is it called throwing?” and checking plans for building a bench wheel, wander the rest of this magazine’s site. You’ll find much to read.Fire and Brimstonewww.peak.org/~patek/potsindx.htm

This one is for inspiration. It’s a gallery filled with Japanese and Chinese pottery of antiquity; a place to see our pottery roots.Native Techwww.nativeweb.org/NativeTech/pottery/index.html

Here you’ll see what the Eastern Woodlands Indians accom­plished without a potter’s wheel and how they did it. Teachers take note: You could turn this into a school project.Jeff Zamek’s Ceramic Consulting Services www.westmass.com/fixpots

Ceramics consultant Jeff Zamek has his own web site where you can read about both shivering and glazing and how to fix them. You’ll also find a description of his book What Every Potter Should Know (more help for those unending potting problems).

Pottery Making illustrated 7

Summer 19998

I very much enjoy making pots that are heavily textured with random and varying surfaces. These seem much like drawings to me— landscapes in porcelain and stone­ware—enhanced and further varied by the glazing and firing processes.

In order to incorporate the random textures possible when handbuilding with the lyrical flow and grace of a wheel-thrown pot, I use thrown greenware forms as press molds for the bodies of pots, finishing the pieces with thrown necks, lips, spouts, lids and pulled handles.

“Indiana Roadside Series: Teapot,” 8 inches in height, porcelain, glazed and unglazed surfaces, reduction fired to Cone 10. Constructing handbuilt textured forms inside thrown forms opens a wide range of possibilities for Texas potter Dannon Rhudy.

Pottery Making illustrated

by Dannon Rhudy

9

PreparationsClay: Any clay can be used for this

method. I use whatever recycled/ shop mix stoneware is available to throw the forms, then use either stoneware or porcelain for the pots. All outer forms are recycled, along with scraps from slabs, etc. I use a very simple “dirty porcelain” recipe (25% EPK, 25% ball clay, 25% Custer Feldspar, 25% Flint), as it’s a bit more forgiving of all the rough handling than Grolleg porcelains are.

Forms: I first throw the forms that I plan to use as “molds” for the work. I use Masonite or plastic bats drilled for pins. I DO NOT want the forms to release from the bat while I’m working, but I DO want to be able to take the form on and off the wheel easily and without re-centering. The forms need to be at approximately a leather-hard stage before they are used.

Slabs: While the forms are drying, I make the slabs that I’ll be using for construction.The slabs may be made by hand, done on a slab roller or thrown on the wheel. I use all of these processes at vary­ing times. The slabs should start out at about ¾ inches thick, as they become thinner during the con­struction process. Keep the slabs as uniform in thickness as possible, to make the building process sim­pler and easier.

Texture: Texture the slabs while they are soft. Anything at all can be used to create texture, from tree bark and fingerprints to the sole pat­tern of your favorite sneakers or hiking boots .You can draw on the slabs, stretch them, wrinkle them or smooth them.

Setting up: After applying the texture, set the slabs aside, textured side up, for the clay to stiffen a bit. If the slabs are too soft when they’re used, then the texture will be lost in the construction process. Ide­ally, the slabs will still be reason­ably flexible but with the top, tex­tured side, somewhat dry. It’s help­ful to dust the textured surface with kaolin to help speed surface drying, and as a bonus, the kaolin responds in an interesting way to various firing processes.

Note: The exterior shape of this form will be a bit thick and clunky looking. Your attention should be on the shape INSIDE the form—that is, the shape your pot will be when you remove the outer shell.

Use a fork to THOROUGHLY score the entire inside of the piece. This is an im­portant step—don’t be timid here.

Dampen the interior slightly with a sponge and use a leather or rubber rib to com­pletely smooth the inside. This is what holds your piece together, so be thorough.

Now, leaving the outer form as it is, throw the coil onto the pot, making the shape needed to finish the piece. Use a needle tool to make a very shallow line between the form and the part you have just thrown. Use the needle tool again to score a line part-way through the form, about an inch down from the upper edge.

Make a perpendicular cut through this ring, and GENTLY peel off this strip of clay. You will note that in most cases you need to correct the line of attachment where the handbuilt and thrown portions meet.

Throw the mold form. Make it thicker than Leave enough clay in the base to incise a a ring for the foot,finished pot would be, particularly at the base.

10 Summer 1999

Step 1 Step 2

Step 6 Step 7

Step 11 Step 12

To ease the removal of the finished work, place a piece of paper towel in the foot ring of the form.

When the thrown form is about medium leather hard, and the slabs have set up enough to maintain their texture, it’s time to start making the pots. Place pieces of textured clay inside the form, textured side against the form. You can use any design you wish, but don’t attempt to fill every space; gaps are okay for now.

Next, fill in the gaps with soft pieces of clay. This is much simpler than trying to fill every little space with drier pieces of slab. Roll a coil and place it in the foot, filling the ring completely. Smooth the in­side gently with a soft, flexible rib—leather or rubber works well.

Step 8

The piece should be like this when you are done: smooth and even. If there are any little dents, push in a little soft clay and smooth again.

Make a coil for finishing the top of your piece. I prefer to throw mine, so that I can make a thin, even flange for attaching to the neck of the piece without fitting prob­lems. Use a needle or wire to cut the coil from the hump or bat.

Invert the coil into the neck of the piece. Adjust for level and gently smooth the flange into place inside.

You can adjust the shape of the neck at this point, too, to suit the now-visible shoulder of the pot. Gently does it.

The interior of your pot should be smooth, even and without voids.Step 13

Make this correction now, while the form is still supporting the piece.

Pottery Making illustrated 11

Step 3 Step 4 Step 5

Step 9 Step 10

Step 14 Step 15

ROUND JUG AND CUP

“Indiana Roadside Series (Hardwood Winter): Round Jug and Cup,” up to 9 inches in height, stoneware, glazed and unglazed surfaces, wood fired to Cone 11.

Dannon Rhudy received her Bachelor of Arts degree from Texas A &M University/Corpus Christi and a Master of Fine Arts degree from the University of North Texas School of Visual Arts. She currently maintains a studio and teaches ceramics and drawing at Paris Junior Col­lege in Paris, Texas. You can e-mail comments to her at potter@koyote.com.

Summer 1999

Step 16

Score the form most of the way to the base, spacing the score lines from one to three inches apart. You may remove the form at this point.

Sfpn 17 ________________ __________

Remove the form most of the way down.

Step 18

Let the piece sit in the “foot” for a while to stiffen, so that it will not distort when you lift it out.

Step 19

Lift it out, peel off the paper towel and voila! No trimming required.

VARIETY OF FORMS

It’s possible to create a variety of forms using this method.

12

COVERED JAR PITCHER

“Texas Roadside Series: Covered Jar,” 10 inches in height, porcelain, glazed and unglazed surfaces, reduction fired to Cone 10.

“Indiana Roadside Series: Pitcher,” 13 inches in height, porcelain, glazed and unglazed surfaces, reduction fired to Cone 10. To maintain the texture, glaze the interior and thrown parts, usually leaving the textured parts unglazed or wiping the glaze off so that it re­mains only in the crevices, enhancing the texture.

BASKETTEAPOT

“Texas Roadside Series: Teapot,” 6½ inches in height, porce­lain, glazed and unglazed surfaces, reduction fired to Cone 10.

“Indiana Roadside Series: Basket,” 11 inches in height, stoneware, glazed and unglazed surfaces, reduction fired to Cone 10.

Pottery Making illustrated 13

Summer 199914

Pottery Making illustrated 15

he “Ohio Governor’s Youth Art Exhibition,”

now in its 29th year, is dedi­cated to the educational and ar­tistic advancement of Ohio’s tal­ented young people. This year’s competition resulted in the se­lection of300 pieces from over12,000 regional entries. Here are a few of the ceramic art entries from this year’s competition. For more information, visit the web site at www.state.oh.us/govart/.

“Raku Slab Vessel,” 18 inches in height, Jason Beard, Clyde High School, Grade 11.

“Land of the Giants,” 42 inches in height, Todd Seeds, Westland High School, Grade 12.

“Orientation,” 10 inches in height,

Amanda Roberts, Hilliard-Davidson

High School, Grade 10.

“The Flowing River,” 20 inches in height, Steve Weber, Hilliard- Davidson High School, Grade 11.

Summer 199916

T

“Wisdom Through Words,” 12 inches in height, Lauren Chapman, Whitmer High School, Grade 12.

“Spiritual Majesties,” 24 inches in height, Emily Collins, Stivers School for the Arts, Grade 10.

Pottery Making illustrated

“Hope’s Lemon Tree,” 19 inches in height, Jessica Brown, Stow- Munroe Falls High School, Grade 12.

“Teapot,” 7 inches in height, Allen Brophy,

Hilliard-Davidson High School, Grade 11.

“Bold Installation,” 2 feet in height, Josh

Barkeloo, Westland High School, Grade 12.

“Square Bottles,” 38 inches in

height, Jeremy Downing, Ada High School,

Grade 11.

17

Tobikannaby Brad Sondahl

The tobikanna (pronounced toe be kah na) is a simple decorating tool traditionally used in some parts ofJapan. Its name means 'jumping iron” which is descriptive

of the way it hops and plunges against a moving clay surface, creating texture and incised decoration simultaneously Since the tool isn’t commonly available commercially; I’ll describe how to make one and how to use it to produce various decorations.

Step 2 - Cut

Using tin snips, cut a strip approximately ½-inch wide, straight across the lid. Smooth any sharp edges or burrs on the strip with sandpaper or a fine file.Tip: If you do not have tin snips, wear gloves to crease the lid near, but not at, the middle. Make a parallel crease ½ inch on the other side. Fold the creases tightly back and forth until metal fatigue induces the metal to break.

Step 4 - Heat

Holding the strip with pliers, heat the metal in sections over a flame (candle or propane torch). As a section becomes glow­ing hot, plunge it in cold water. This tempers the steel, convert­ing it to spring steel, so that it will tend to retain its shape when used. Repeat the process until the whole strip has been heated and plunged. The tobikanna is now ready for use.Warning: Steel readily transmits heat and will get hot far from the direct heat source. Do not handle the heated metal until it has been plunged in water.

Summer 1999

Making the TobikannaTobikannas can be made of any thin, springy steel.

In the example here, I used the lid of a tuna fish can,

Step 1 - Flatten

Pound the lid flat with a hammer against a hard smooth surface (such as a brick or cement floor) to remove any ridges.

since these are readily available and standard in size. Use of unusual tools is kept to a minimum.

Step 3 - Bend

Bend one end of the metal strip into a smooth curve, with the tip approaching a right angle to the rest of the strip.

Using the TobikannaThe flexible tobikanna tool produces a variety of deco­

rative effects. Use it on freshly thrown or leather-hard clay or carve through oxides or slips to expose part of the clay body underneath. But let s start with the basics.

The tobikanna works by digging into soft clay as it s spinning on the wheel, catching for a moment, bending

then springing free, only to recontact and repeat the cycle many times per second.

In the following illustrations, I’ve applied red iron ox­ide to the pot to make the effects of the tool more visible.

Step 1 - Color

Apply a band of iron or slip to a fresh or leather-hard pot.Tip: Beginners will have better luck with a leather-hard pot secured to the wheel head with wads of clay. Advanced throwers may find that decorating pots while still centered is highly effi­cient. Note that the tool makes larger marks on softer clay.

Step 2 - Score

Score lines through the iron to mark the limits of, or add rhythm to, the decoration. I use a strip of plastic credit card with a pen­cil-tip-shaped end for this.

Step 3 - Chatter

Use a moderately fast wheel speed. Hold the tool at its straight end so the curved end contacts the pot as it turns. Try changing angles until chattering occurs. Also try holding the end tighter or looser and try varying the pressure with the tool contacts the pot. If you’re just scraping a steady line, slightly apply more pressure. Once the tool starts hopping, move it slowly up or down so the pattern will fill the allotted area.Tip: There are a lot of variables to holding the tool, as well as speeds of the wheel, so keep trying the different techniques suggested until it catches. Once achieved, it’s easy to master.

More EffectsOnce you’ve gotten the tobikanna to chatter,

consider the following decoration possibilities.• Apply a dark slip to a light clay body, then make

one pass with the tool through the dark slip to create an effect that’s like snowflakes or polka dots.

• Create a unique overall texture by making mul­tiple passes to obscure the individual nicks of the tool.

• Achieve a subtly ancient-looking effect with a bold painting of engobes on a pot, then observe how each pass slowly wears away at the under­lying decoration.

• Combine the tobikanna technique with combed waves of sgraffito.• Accent the texture by applying tobikanna to a

leather-hard pot, which is not otherwise deco­rated, then bisque fire the piece. Next, brush red iron oxide over the chattered area, and wipe off the iron with a damp sponge. The deeper nicks retain more iron, and the result will be dark notches on a lighter background. Use a transparent matte glaze (e.g., Sondahl C-4 Matte) to get the best effects.

Pottery Making illustrated 19

Vase with tobikanna applied at the leather-hard stage with iron oxide brushed on and sponged off after bisque. Vase with sgraffito and tobikanna deco­

ration through a cobalt slip.Vase with tobikanna and sgraffito through iron and manganese slips.

Tobikanna can also be applied to flat sur­faces, such as this platter.

A frequent contributor to Pottery Making Illustrated and Ceramics Monthly, Brad Sondahl learned the ways of tobikanna while apprenticing with Chris Holmquist in Northfield, Minnesota, who learned the technique while working in fapan. Currently, Brad has studios in Nezperce and Spirit Lake, Idaho.

Summer 1999

Recipes

Sondahl C-4 Transparent MatteCone 8—10 oxidation

Dolomite..............................23.4Whiting................................ 13.5Custer Feldspar.................. 23.4Frit P25 (Pemco).................13.5Kaolin..................................23.4Bentonite.............................. 2.8

100.0Blend the bentonite with water in a blender before adding to the glaze. Use this glaze thinly—effective over iron and manganese slips. If this glaze crazes or is not transparent, thin it more with water. One quick dip will coat a pot sufficiently, or even brushing one coat on can be effective. Apply Sondahl Magic White over this glaze for areas of the pot that would benefit from a gloss surface.

Sondahl Magic WhiteCone 8—10 oxidation

Spodumene.......................... 5.0Whiting................................. 20.0Zinc Oxide............................ 6.7Zircopax............................... 16.6Custer Feldspar................... 21.7Kaolin...................................10.0Flint...................................... 20.0

100.0A white gloss opaque glaze that shows un­derlying copper or cobalt slips well.

20

EngobesEngobe (or slip) recipes work on wet or leather-hard clay, broad firing range. Tips: Slips need to be thick to be applied, particu­larly to freshly thrown pots. You can gauge the correct thickness when you are applying them—too thick and it will be impossible to make a clean band of decoration; too thin and the clay body will show through. To sieve engobes, it may be easier to add extra water before sieving and decant the excess water when the mixture has settled in a day or so.

Beige Speckled SlipBall Clay..............................72.0Kaolin.................................. 25.0Red Iron Oxide..................... 3.0

100.0

Add: Granular manganese(40-60 mesh)............... 12.0

Warning: Manganese is toxic, including as it vaporizes in the kiln. Granular ilmenite, granular rutile or granular magnetite may be substituted in place of manganese in this recipe. Mix the first three ingredients with wa­ter to a thick cream consistency, sieve the mixture, then stir in the manganese.

Blue Cobalt SlipBall Clay...............................87.0Cobalt Carbonate................. 7.0Black Cobalt Oxide.............. 6.0

100.0Add black cobalt oxide to make the slip more visible when it is applied (as well as more blue), since tiny specks of it in the wrong place may ruin a pot’s decoration. Substitute cobalt carbonate for the cobalt oxide if you wish, but tint the slip with food color or dye to improve its visibility. This slip shows through the Magic White glaze well.

Throwing Bottom First

After a few tries and a little practice, you should have no problem making your pots the size and shape you desire. Here are just three examples of the variations of forms that can be made by throwing the bottom first—a throwing method that requires no trimming.

Ve been a ceramics artist since 1962 and for many years I made bottle or bubble-shaped forms by the conven­

tional method of throwing.Toprevent slump­ing, I would often resort to torch drying or blowing into the closed forms to reinflate them, then wait for the pot to dry for the

final trimming of the foot, ending up with piles of trimmings that required recycling.

The solution followed from an extension of an idea that I first took note offrom an article titled “Throwing a Pot from Both

Pottery Making illustrated 21

by Don Adamaitis

i Ends” by Wayne R. Anderson (Ceramics Monthly, Jaw. 1981). After a little prac­tice, I found his technique very satisfying, and it created the seed that developed into the following method I presently use for throwing most of my large planters and bubble-shaped ceramic forms. By throwing a pot at both ends, I’m able to create ceramic

forms that require no trimming and are nor­mally only achieved by the coil or slab

method.

Don Adamaitis has been an active potter since 1962. He has a degree in the physical sciences, with major studies in physics, geology and chemistry. While working for the Saudi ARAMCO Oil Company in Saudi Arabia, he contin­ued his ceramic art as the coordinator of the ceramics area of the art groups in Dhahran andAbqaiq. Since his retirement in 1987, he has devoted his atten­tion to glaze chemistry and various types of kiln construction (see “Building a Domed Cylinder Kiln—Part I” on p. 40). Don refers to himself as an eclectic ceramics artist, exploring all areas and types of ceramics.

Figure 1. After centering a ball, flatten it so the outside diam­eter of your clay disk is the diameter of your intended pot.

Figure 2. Open the clay to about half the diameter of the clay on the bat, then raise your hand off the bat about ½ inch and continue opening. This leaves a clay base-ring and holds your clay securely to the bat.Tip: I normally form a slight berm at the bat-clay interface of the opening to form a reservoir for the water rundown within the pot, which prevents saturation of the bat. This berm is left with a slight amount of slip-water in it and will keep the clay base damp.

Figure 3. Throw your clay upward and inward, thinning the walls as you raise the clay. This is the same method you would do if you were throwing a closed form. As you pull the clay upward, remem­ber not to throw into the form’s lip. Always stop your pull about ½ inch from the top and hold your hand position for two to three revolutions. This prac­tice prevents the lip of your pot from rising and falling as it turns due to more clay on one side of the lip. Decreasing the pot’s diameter as you’re throwing lessens the chance of clay torque. Once you get to know the limits of the clay body you’re using, you can move the clay upward and inward very rapidly with very little throwing water.

Figures 4a and 4b. If you plan to add a foot ring to the pot: continue to throw the wall upward and inward forming a thicker, collar-type neck. To create the ring for your foot, use a needle tool to cut-off a ring of clay. Set it aside to be attached after closing the pot. Take note that the cut off point for the foot ring has to be less than half the height of the collar-neck of your pot. This is to allow enough clay to be left on the thrown form to complete the closing of the form. This will allow the walls and bottom to be a consistent thickness.

Figure 5. With a sponge on a stick, remove any excess water from the bat surface and allow a “small” amount of slip-water to remain on the clay base of your form. At this point, continue the upward and inward throwing, forming a small nipple-type spout.

Figure 6. With your needle tool, make a 45Q cut at the base of the nipple spout. Do not wet this cut surface, since slip on this surface prevents a good seal from occurring and leaves a lump of slip inside the pot.

22 Summer 1999

Figure 7. Collar the hole closed with your finger by moving clay from the outside surface only, then flatten the surface with a rib tool or your finger. If your pot surface seems to have an uneven arc, you can shape the surface by dampening and shap­ing it with a thin metal rib. Trapped air inside the form prevents collapsing, and a smooth shape of the bottle/pot can be formed.

Figure 8. If you intend to add a foot ring, do so at this time. Lightly score the surface of the closed form and the bottom of the foot ring you made earlier (see fig. 4b). Dampen the scored surfaces with vinegar. Add the foot ring and center. With a wooden tool, “wedge” the clay at the base of the ring to the pot. Do this on both the outside and inside of the foot ring. With your finger or tool, throw the wedged area of the added foot ring and the pot together to make a smooth joint between the two. The trapped air inside the pot should allow you to work on the foot ring without distorting the form.

Figure 9. If you do not wish to add a foot ring, you can make the foot by lightly depressing the center of the closed form and moving outward until you have a flat inside diameter of the foot. Then lightly depress the form on the outside of this depressed area to form a foot. With a thin metal rib or your finger, throw on the outside, making a smooth arc to the foot ridge. The air trapped inside will support this form of a thrown foot.

Figure 10. With your needle tool, make a tiny hole near the base of the closed form to allow air to escape due to compres­sion and shrinkage as the form sets up.Note: Check that the center of the “flat base” of your form’s foot is still flat. Sometimes the center slightly rises before you make the air release hole with the needle tool.

Figure 11. With your wooden tool, make a slight inward cut at the base of the pot and remove this clay.

Figure 12. Run a cut-off wire under your pot, freeing it from the bat to allow for shrinkage. Because of the damp weather in southwest Washington and the slow drying, I only cover my pots with a light cloth and let them sit overnight before continu­ing. The watery slip left inside the pot during opening will keep the bottom clay moist as the rest of the pot begins to dry.

Pottery Making illustrated 23

Figure 13. Remove the pot from the bat when its surface is in the soft-leather-hard state and you can handle it without distor­tion. Carefully nestle it into the chuck and center. Once the pot is centered and level, secure the pot to the chuck by adding dabs of clay between the pot and the chuck. This is necessary to hold the pot securely while you are throwing the top portion.

Figure 14. Dampen the surface of the overhanging clay, care­fully throw upward and inward in a smooth arc. Create a closed form as you did for the bottom of the pot. The amount of clay you left in the first opening procedure will determine the de­gree of closure you will be able to achieve.

Chucks are used to hold pots for addi­tional throwing or trimming. You can use pre-thrown bisque chucks, as shown here, or you can throw a raw clay chuck and allow it to dry to leather hard. Se­cure a chuck to the wheel head with wads of clay prior to use.

24 Summer 1999

by Chris Campbell

Birdhouses, 10 inches in height, porcelain paperclay constructed from tex­tured slabs, fired to Cone 6.

y adventure with textures began in my first pottery class. I had finally thrown and trimmed a cylinder that was higher than

the clay I started with. I immediately hurried outside to find an interesting seedpod to press into the surface. When I saw how the fired glazes pooled into those marks and

felt the finished pot in my hands, I was in love. From that day on, my pots became objects to alter and texture. I draped them with slip-soakedfabric, stamped them with homemade stamps, added clay and washed clay away

from resisted patterns. I was definitely not inclined to leave well enough alone.

The needfor a broader “white canvas” led me to hand- building with very soft slabs of porcelain. Working with very soft clay allowed me to keep my designs fluid and alive. I now use porcelain paperclay (see box) for its extra strength and warp resistance. I design textured wall mu­rals, tiles, mirror frames, centerpieces, vases and decorative

birdhouses. Interesting surfaces mimicking wood, tin, sid­ing and bricks are created using a variety of found objects and a full palette of slips, un­derglazes, oxides, stains and glazes accent textural effects.

Pottery Making illustrated 25

PH

OTO

S: T

ER

RY

CA

MP

BE

LL

M!

ProcedureI wanted the birdhouses to look as though they had

been made from junk materials that you could find in a garage or attic.They had to appear to be bolted together in a haphazard manner. My challenge was finding ways to create the look of fiberglass, paneling, fake brick, metal, old boards and weathered wood.

For coloring the slabs, I use underglazes, oxides and slips. I make my slips in a blender using my porcelain clay body, Mason stains and water. I keep them as thick as yogurt so that they don’t add needless moisture to the slabs. For safety’s sake, I always wear rubber gloves dur­ing this messy work with colorants in case I have any small cuts on my hands. Also, I never use this blender for food.

I apply the colorants with sponges, loofas, towels and all varieties of brushes, dried fungus and tree bark. Re­member that clay shrinkage affects all surfaces, so you need to make the impressions deeper than you want the fired surface. If lace or leaves get stuck, just leave them in place and they will fire out without damaging the pattern.

You can paint over some slipped sections with Forbes wax resist. As it dries, it pulls and leaves a pattern that resembles a cracked riverbed.

I cut the slabs to the proper shapes and leave them on racks to set up. I like to use the clay long before it is leather hard because I don’t like the “dead” rigidity of a hard piece of clay. Even when building a structure like a house, I like to feel movement.

Since many of my slip colors mature at Cone 6, I reverse my firing process. I fire to Cone 6 first to mature my clay and slip colors. Then I apply the underglaze colors such as red, pink and violet that would fire out at high temperature and refire to Cone 06. I then apply two coats of clear glaze. Since I am glazing a mature fired surface, it helps to warm the piece. It will take a while for the glaze to dry. On some surfaces, I add one coat of a specialty glaze, such as a crawl or lichen glaze, then fire again to Cone 06.

Sometimes a project is a failure and it’s hard to see all of your hard work go for nothing. I was asked to create a “Rainforest” house for a client. The first house turned out badly overdone, but I was so delighted with the tin roof that I couldn’t bear to face the truth. I kept adding to it and fiddling with it and refiring it until I could finally face the fact that it was never going to work. I learned a lot of techniques along the way, but also learned a bit about what you can and can’t fix. I can’t fix the fact that I am going to keep trying until the bitter end. (I still really like that roof.)

Try some of these techniques but keep pushing your­self further. You’ll learn more from your mistakes than you will from caution.

The first place I always look for texture is in my home and yard. I then spread my search to the hardware stores, the kitchen shops and fabric outlets. I don’t throw away anything until I con­sider its value as a texture. I’ve glued chopsticks, skewers and dowels onto boards at measured intervals for wavy patterns. I save springs, tops and tubes from old spray bottles and ballpoint pens. Shells, coral, bark, leaves and dried fungus make great textures. I’ve used bubble wrap, humidifier filters, corrugated cardboard, grates, old gears, bolts, mesh bags, cheesecloth, screens, towels, socks, phone cords, chains and bolts.

Mesh Bag and DowelsTry placing a texture like this mesh bag between the

dowels and the clay.

26 Summer 1999

Stone WallI needed to find a way to make a stone wall for a

commissioned piece. I cut up a piece of carpet underpad, hoping that the rolling pin would force the clay into the holes and leave a textured mortar look in the spaces. I dabbed on two or three “stone” colors and some green for moss. I was very pleased with the results.

My Unscientific Homemade Paperclay

Prepared clay (any kind) 25 lb.Single-ply toilet paper 1-3 rollsBleach (optional) 1 tbsp.Unroll the paper and soak it overnight in water. Stir well, then squeeze it out well and mix it into the clay. I use an old restaurant-grade Hobart mixer that I bought second -hand at a restaurant-supply house. The amount of pa­per used determines how easily it will cut into slabs later. Play around with the amounts and see how it works for you. This paperclay will start to smell after a few weeks and that is the reason for the bleach. I don’t bother to add it because I use the clay quickly.

RecipesMark Messenger’s Crawl Glaze

Cone 06-04Borax................................... 3.9Gerstley Borate....................46.5Magnesium Carbonate........31.0Edgar Plastic Kaolin............ 18.6

100.0Add: Zircopax......................... 5.4

Apply over other glazes either fired or unfired. Appearance of glaze changes with firing tem­perature: Cone 04, glassy beads; Cone 06, dry platelets.

Lana Wilson’s Lichen GlazeCone 06

Magnesium Carbonate....... 40.0Gerstley Borate...................50.0Borax.................................... 5.0Kentucky Ball Clay.................................. 3.0

98.0Apply over other glazes, either fired or unfired.

Steve Loucks Low-fire ClearCone 04

Gerstley Borate....................55.0Edgar Plastic Kaolin............ 30.0Flint..................................... . 15.0

100.0Mix to a heavy cream consistency. Add Ep­som salts until it stays in suspension.

Pottery Making illustrated 27

Weathered WoodI create weathered-wood effects by layering colors

and scraping between each color. Any clay caught in the tools is thrown back on and patted in place. Any rips are left to keep the appearance of beat-up boards. The final touch with wood is in the last firing when I use specialty glazes to produce the crusty lichen and crawl effects seen in photo 5.

Rippled EffectCover one side of the clay slab with underglaze or

slip. Put a sheet of paper over the dowels to prevent sticking. (Tip: I use pages from old telephone books, as they are cleaner and sturdier than newspaper.) The slab goes on the paper, then is pressed down firmly with a sponge that has been lightly soaked in colored slip or underglaze. Another color can be added on the raised areas for a pleasant contrast.When you lift the clay, you’ll find you also have an interesting texture on the back.

28 Summer 1999

Fake BrickI create the fake-brick look by carefully measuring

and marking the slab with the handle of a needle tool. I color these lines with black underglaze, then use a brush to spread the black slightly over the slab. I use a cut-up filter pad to dab on the terra-cotta color. I also use a toothbrush or spatter brush to add accents of purple and white.

Pottery Making illustrated

A potter for 12 years, Chris works as a full-time studio potter in Raleigh, North Carolina. She learned her craft from generous teaching potters who shared their skills and love of pottery in classrooms and workshops. See more of her work on the Internet at www.wholesalecrafts.com. If you have any ques­tions or wish to share your discoveries, you can contact Chris by e-mail at CCPottery@aol.com. Terry Campbell has been an amateur photographer for over 20 years and now specializes in craft photography.

29

Clay Draw Plane

A clay draw plane enhances precision, rapidly cuts clay, is relatively cheap, resists corrosion and is easy to make.

’ve seen instructions for con­structing slab-built pots and sculptures where the corner

joints were prepared by slicing ver­tically into the prepared clay slab to create the shapes, then the edge of one slab was butted to the surface of another after scoring and coating with a wet slurry. The disadvantage of this technique is that the clay needs a considerable amount of fettling af­terward to remove the unsightly scars that remain. When presented with the chance to make some tall elegant bonsai planters for cascade displays, I reviewed this process and thought that there might be a better way to prepare and finish the joints. Since carpenters and picture framers use miter cuts on the ends of moldings and framing pieces to conceal the edge of the wood and to provide a neat fit when assembled, I thought I could use this system with clay slabs.

My first attempts were crude be­cause I could not control the angle of the cut as I passed my knife along the edge of the ruler. To overcome

this problem, I designed and made a clay draw plane, a small implement that aids in precision cutting. When pulled along the clay, it cuts a miter face with a consistent angle along the edges of each piece. The parts are assembled and minimal cleanup is re­quired to get blemish-free sharp edges. This high-quality finish en­hances the aesthetic value of my pots.

These small but useful tools aren’t difficult to make from hard-rolled brass sheet, which is available at hobby shops. In this example, I used 1-millemeter-thick brass. The mea­surements are for a tool that will cut miters along clay slabs that are 10 millimeters thick. Cutting was done with a jeweler’s saw fitted with a 4/0 blade. Each cut required only a slight touch with a fine file to give a well-dressed edge. Bending was done by clamping the metal between two blocks of wood so the fold mark aligned with the edges of the blocks. This assembly was clamped in a vise and the free metal pressed over. A sharp crease results if the metal is beaten with a mallet.

Making a Clay Draw PlaneStep 1. Cut a rectangle of brass plate to size (50x70 mm). (Tip: Use a saw—metal shears can distort or bend the flat sheet.) Be sure to see that all corners are right angles. Dress the raw edges with a file. Mark out the design on the metal. Precise mea­surements are given in the diagram (see fig. 1).Step 2. Saw out the corner tab where the handle will fold up, then saw out the triangle to relieve a pointed tab that will fold down to become the cutting blade (see figs. 2 and 3).Step 3. Secure the metal between wood blocks and fold the handle tab upward. (Tip: This is easily accom­plished if another section of wood is held against the metal then pushed or struck firmly with a mallet to press the metal over.) Locate the side guide plate between the blocks of wood and fold this downward, opposite to the handle tab.

Secure with the triangle cutter pointing upward from between the

30 Summer 1999

by Ivor Lewis

I

wooden blocks. Check this for align­ment. The fold must be parallel to the fold of the guide plate. Fold the metal tab halfway, turning it through an angle of 45° in the same direction as the guide plate. Check this with a 45° set square and adjust to get a pre­cise alignment.Step 4. Trim the excess point away with your saw and dress the edge so that the tip of the cutter is in align­ment with the guide plate. File the sloping edge of the blade to sharpen it so that it makes a clean cut along the clay.

Using a Draw PlaneMark all slabs and cut them all ver­

tical edges at 90° so the side guide (b) of the cutter can rest against it. Don’t let the clay become leather hard, but do not allow it to be damp or tacky either since the cutter will bind. (Remove moisture by dressing the clay with a light dusting of corn starch.) Hold the tool so the guide is against the vertical edge of the clay, then pull it toward you. The cutter will bite into the clay and shave off a triangular fillet, leaving a clean, pre­cise beveled edge (fig. 4).

A clay draw plane enhances preci­sion by guiding the cut along a straight edge. As an added advantage, the de­sign can be modified for a different thickness of clay by changing the depth of the cutting guide to suit differing guide rails. Those who use thicker or thinner slabs can recalculate the dimen­sions of the side plate and the cutting point.The design is not registered and there is no patent. I hope those readers who enjoy slab work will make their own draw planes and enjoy using them.

Figure 1

Begin with a piece of hard-rolled brass measuring 50x70 mm and transfer the cutting and folding lines onto the surface as indicated in this drawing.

Figure 3

Three folds create the handle (a), the side guide (b), and the cutting edge (c). Cut the tip from the cutting edge after forming the 45Q angle.

Place the clay draw plane at the far edge of the trimmed slab, then pull the cutter toward you in a smooth continuous motion.

Ivor Lewis is a retired teacher of arts, crafts and science. He maintains an interest in practical pot­tery and is a frequent contributor to publications in many countries. He can be contacted at ivorredhill@yahoo.com.au or by writing to Box 10 CMA, Redhill, South Australia 5521.

Pottery Making illustrated 31

Figure 2

After cutting out the corner and notching for the blade, the clay draw plane is ready to fold.

32 Summer 1999

When working in the ceramics studio, there are situa­tions where eye protection is needed. While working with ceramic materials is not an inherently dangerous endeavor; using the proper safety equipment can help the potter easily avoid a few potentially hazardous situations. Fortunately; eye protection developed for use in several major manufac­turing areas such as foundries, steel mills, glass production, metal fabrication and casting industries, is readily available to the studio potter.

Infrared/Ultraviolet HazardsIn the past, glassblowers were subjected to infrared and

ultraviolet light when looking into high-temperature mol­ten glass tanks.They developed “glassblowers” ailment after years of unprotected high-duration exposure, and the cu­mulative effect caused cataracts to develop in their eyes. Sometimes the exfoliation of the eye lens was a gradual process that went unrecognized until the damage was se- vere.Today, the causes of glassblowers’ cataracts and the pro­tective methods to prevent such eye damage have made this condition a historical curiosity. (Source: Ralph Chou, “Optical Filters and Radiation Protection, published in Eye Injury Prevention in Industry, 2nd ed, edited by E. McRace and M. Grimm, June 1994.)

Infrared and ultraviolet radiation are part of the electro­magnetic spectrum with visible light being just one seg­ment of the entire range. Infrared radiation cannot be seen

Always wear the correct safety glasses whenever looking into a firing kiln (bisque, raku, glaze, etc.). Keep a safe distance away from the cone-viewing hole when using glasses. Do not use regular sunglasses as they do not offer safe levels of pro­tection against infrared and ultraviolet light from the kiln.

Pottery Making illustrated

as it is composed of wavelengths that are longer than visible light, and ultraviolet radiation is also invisible consisting of shorter wavelengths than visible light. During a kiln firing, both infrared and ultraviolet radiation are released.

While the effects of infrared and ultraviolet light dam­age to the eyes are cumulative, and the process of firing a pottery kiln contains the same elements of exposure to invisible radiation, the duration of each exposure and cu­mulative rates of exposure are less than what glassblowers experience. But even though potters look into a firing kiln for seconds at a time, they should protect themselves from infrared and ultraviolet radiation since the alternative of not using protective glasses can result in potentially serious eye damage. By using the proper eye protection, potters can avoid any potential long-term risk to their eyes.

StandardsWhen considering infrared/ultraviolet eye-protection

glasses or goggles, make sure the product meets the ANSI (American National Standards Institute) standards. Always look for the ANSI Z87.1-1989 label on the glasses, in­struction sheet or box. However, note that the ANSI stan­dards for protective eyewear are extensive and some prod­ucts with the ANSI Z87.1-1989 label might not be suit­able for infrared/ultraviolet light protection.Therefore, look for a green shade designation of #5 or above.

Infrared/Ultraviolet Eye Protection GlassesI tested black-frame cobalt-blue #5 infrared glasses

(model MR9140) sold by Sheffield Pottery Supply .These glasses have lenses that filter out 70% of infrared light in the 780-2000 nanometer (unit of measurement, one billionth of a meter) ranges and 99.9% ultraviolet wavelength light; however, the polycarbonate lens has a darker tint than stan­dard green-shaded welding glasses. Green-shaded welding glasses or goggles range from numbers 1.2 to 16, with the higher numbers offering greater degrees of protection against the infrared light spectrum. (Source: Eye Injury Pre­vention in Industry, 2nd ed., edited by E. McRace & M. Grimm, 1994, Table 3, Transmission Specification for Fil­ters, p. 22.) At some point, a trade-off has to be made, since higher shade numbers block more light, making it more difficult to view pyrometric cones during the firing.

The cobalt-blue #5 lens is rated on a different scale and does not correspond to the green-shaded welding glasses #5. While this dual-numbering system might be confusing, the cobalt-blue #5 glasses have an advantage over green-shaded welding glasses #5, as they filter out a greater amount of the infrared light spectrum. The im­portant point being the Cobalt Blue #5 Model MR9140 glasses offer eye protection up to 2700°F, or approximately Cone 17, well above the temperatures reached by most potters.This model also meets or exceeds several industry standards for eye protection encountered in infrared and ultraviolet light conditions.

33

by Jeff Zamek

I found the glasses comfortable to wear with a flip-up shade that reveals a set of clear lenses.The glasses have side shields that are an added eye protec­tion safety feature.The cobalt-blue #5 glasses are rated at 0.2%VLT, or visual light transmission, while green-shaded #5 welders glasses are rated at 2%VLT (the lower theVLT percentage, the less visible light that can be seen through the glasses) .This made it harder to view the pyrometric cones during the fir­ing as compared with green-shaded welders’ glasses, but there are a few pro­cedures to help make viewing cones better while wearing the glasses (see box).The Model MR9140 glasses are more expensive than most other prod­ucts of similar type, but the extra pro­tection is worth any price. Eye protec­tion is not an area to cut costs in any studio operation.

Shielded Headgear and Safety Glasses

Several activities in a pottery studio require safety glasses or face shields to prevent eye injury. The most hazard­ous activity is scraping kiln wash or glaze drips off kiln shelves. Many pot­ters use a high-speed grinding wheel to remove glaze drips or rough sur­faces from their pots, creating a dan­gerous situation where hard projectiles may be thrown off the spinning wheel that can then hit soft body tissue. Mix­ing slips, clays and glazes is also haz­ardous, since liquids and dry materials can spatter in all directions.

Safety glasses offer eye protection, but shielded headgear provides a greater degree of covering for the en­tire face and neck. Either type of eye protection should be employed when­ever there is a possible risk from liquid or solid flying objects.

All eye safety goggles and headgear shields should meet or exceed govern­ment OSHA/ANSI Z87.1 (Occupa­tional Safety & Health Administration/ American National Standards Institute) standards for eye protection. The label ensures the safety device has been tested for impact and penetration resistance, corrosive factors and optical clarity.

Wilson Headgear & Visor SetI tested a Wilson headgear and vi­

sor set from Sheffield Pottery Supply. At first the headgear and visor felt a little top heavy, but after I adjusted the head strap, it proved to be very com-

Whole-face protection offered by a safety shield is better than limited eye protection from safety glasses. Keep safety shields or glasses in an easily accessible place.

fortable. I have no doubt that any slight inconvenience of wearing the head­gear and accompanying visor will be more than offset by the eye and face protection offered by this industrial- quality safety equipment.The grading system for scratch resistance in visors has poor, fair, good and excellent rat­ings. The clear propionate visor has a rating of good for scratch resistance. The visor’s resistance to scratch marks is an important value-added feature for a long service life.

With the Wilson safety shield in place (and wearing protective gloves), I used a high-speed grinding wheel to smooth the bottom edges of fired pots. When I applied greater pressure against the grinding wheel, two ½-inch-size chips flew off the pot. One landed about 10 feet away and the other hit the bottom section of my face shield, bouncing off but causing no damage to the shield or my neck. After such “real life” testing, I would recommend the face and upper neck protection offered by this headgear and visor set.

Jeff Zamek works as a ceramics consultant, residing in Southampton, MA, and is the author ofWhat Every Potter Should Know (Krause Publications). Con­tact Jeff by e-mail at FIXPOTS@aol.com

34 Summer 1999

Tips for Viewing ConesThere are a few ways to improve the

viewing of cones during firing:• When loading the kiln, paint a kiln

wash of flint and water onto a soft brick and place the brick behind the pyro- metric cones. The white background of the soft brick offers a contrast to the cones during the firing.

• Paint red iron oxide in vertical or hori­zontal stripes onto a soft brick to pro­vide a contrasting background pattern for viewing cones. Don’t paint the cones with iron oxide or any contrast­ing coloring oxide as it interferes with the melting properties of the cone.

• Cut 1/4-inch horizontal or vertical lines into a soft brick to offer a contrasting background pattern for viewing the cones.

• Shine a flashlight into the kiln to in­crease the visibility of the cones dur­ing firing.

Resources• ANSI Z87.1-1989 Standard, American National

Standards Institute, 11 W 42nd St., New York, NY 10036; (212) 642 4980; web site http://www.ansi.org

• 1999 Annual Book ofASTM Standards,Vol. 15.02, Designation: C1023 Section X2.41, page 321. American Society for Testing and Materials, 100 Barr Harbor Dr.,West Conshohocken, PA 19428-2959; phone (610) 832 9500, fax (610) 832 9555;web site http://www.astm.org.

• CSA (Canadian Standards Association), 178 Rex Dale Boulevard, 80 B COKE, M9W1R3, Ontario, Canada; (416) 247-4000, (800) 463-6727; web page http://www.csa.ca/about_csa/index_loca.html

• The cobalt-blue #5 infrared/ultraviolet glasses and the Wilson headgear and visor evaluated in this ar­ticle were purchased from Sheffield Pottery, Inc., U.S. Route 7, P.O. Box 399, Sheffield, MA 01257. Check with your local pottery supplier for availability.

AcknowledgmentsNancy Balin, MD, F.A.C.S., Northampton,MA,pro­

vided a detailed explanation of eye disorders and the safety factors that can be employed to prevent potential eye injury.

Mike Shelto, Pres, of RMS Industries, Box 773, Rocky Hill, CT 06067, provided technical infor­mation on Uvex industrial protective glasses (Co­balt Blue #5) for protection against infrared and ul­traviolet radiation.

Dave Koch, Sr.Tech Specialist, Dalloz Safety Group, PO Box 622, Reading, PA 19603, was most infor­mative about Dalloz products; 800-977-9177.Thank you for supplying information on shielded head­gear and face protection equipment.

Michelle Breen,Tech Specialist, Dalloz Safety Group; supplied technical data on safety shields.

Kirk Van Pelt, Tech Specialist, Dalloz Safety Group, supplied additional information on the Wilson Safety Shields and safety procedures.

Dave De Vries, Dir. of Practices and Standards, American Society of Safety Engineers, was very generous with his time and expertise in directing my research in the areas of preventing infrared and ultraviolet hazards.

Pottery Making illustrated 35

Measure for Measureweighed out batches of glaze and measured each material before dumping it in the bucket. (Borrow a scale if you have to.) I also kept a chart of how much each material weighed in quantitites of ½, ½ and 1 cup for basic glaze materials, such as feldspars and clays, and 1- teaspoon (tsp) and 1-tablespoon (tbsp) quantities of colorants and additives.

In developing a chart, I weighed each material six times using two methods. In the first method, I filled the measuring cup by pouring the material into it, then leveled the material with a straightedge. For the second method, I scooped the material with the cup itself, which packs the material more and thus weighs more than the poured method. In both meth­ods, you have to weigh each material in each of the quantities, because ½ cup ofnepheline syenite does not necessarily equal twice the weight of ½ cup of the material.Important Note

I use only glazes converted to volume—it saves me an im­mense amount of time I would rather spend on other things. But, as with any glaze, you must always test each new batch before its applied to that all-important Order or That Essen­tial Show Piece (not to mention A Whole Years Production!).Special Tip

The volume method is especially useful if you need to mix glaze at a summer camp or other underequipped facility. Here, all you have to do is use cottage cheese or yogurt containers, put the weighed-out glaze material in, hold the container (gen­erally translucent) up to a strong light at eye level and draw a line with a permanent marker just where the material “ends.” Write the name of the material and the glaze on the container, and you’re ready to hit the road!

he volume method—the way America bakes— has a lot going for it. We use measuring cups and spoons in the kitchen to weigh out flour,

sugar, etc., but the measuring method also has as many advantages in the studio when mixing glazes and slips.While measuring cups (and substitutes) lack the prestige and piz­zazz of metric laboratory scales and more “scientific” mea­suring devices, they do offer the advantages of economy, accessibility and common sense.

While measuring ingredients by volume is unlikely to work for finicky glazes, itworks surprisinglywell fbrthe common three- to six-ingredient workhorse glazes typically used in studios or classrooms. It must be remembered that no matter how carefully we weigh our glaze ingredients, the resultant glazes vary because of the inevitable changes in the materials, but also because most materials have the capacity to absorb amounts of moisture (hy- groscopicity), which also affects the actual weight we get.

Cookbooks demonstrate that weight-per-volume does not translate the same way for each material. Flour yields 4 cups per pound, sugar only 2. Likewise with glaze materials.Adapting GlazesTo adapt my glazes, I started with small batches and made

tests, then added materials as needed. Since I own a scale, I

Figure 1. From left to right: DB1 tinted light blue, Behrens with Carol’s Green on knob and blue stain brushwork, BB over slips.

Figure 2. From left to right: The three De Boos glazes: DB2, DB1, DB3

Figure 3. From left to right: Carol’s green with cobalt decoration, DB3, Medi­terranean Green over white slip brushwork on body and black slip on lid.

36 Summer 1999

by Lili Krakowski

T

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S: S

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ULR

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Clayart GreenCone 6

Strontium Carbonate............1 tbspWollastonite......................... 2 tbspNepheline Syenite.............. cupFlint...................................... 2 tbspTin Oxide.............................. 2 tspCopper carbonate.................1 tspA light blue green—of the barium/strontium variety. Crazed on commercial body, not mine. Adapted from Clayart (on the Internet).

Throughout my tests, I used standard U.S. measuring cups and spoons except where commercial yogurt or cottage-cheese containers or bottle caps were used. I very much doubt Imperial measuring cups and spoons would make a noticeable differ­ence. The possible variety of “measuring containers” is infinite—from laundry deter­gent tops (from ½ to ¾ cup depending on brand and bottle size) to soda-bottle caps (11/4 tsp). (The bowl in the photo is full of some of the test tiles this project required.)

Note: Use the measurements in the following recipes as a starting point only. With the volume method, line blends are enormously useful.

De Boos DB1Cone 6

Dolomite.......................Va cup + 1 tspNepheline Syenite . V4 cup + 1 tbsp

Ball Clay..................................... 1/2 cupFlint............................................ 2 tbspAn almost-clear glaze with very attractive tex­ture. Great potential for opacification and col­oring. Works well on leather-hard clay.

De Boos DB2Cone 6

Whiting....................................... ½ cupNepheline Syenite ... 1/4 cup + 1 tsp

Ball clay........................... ½ cup (2X)*Red iron oxide...........................2½ tsp

Rich brown. Works well on leather-hard clay.* Two V4 cup measures is not necessarily the same as a single ½ cup measure. See “Adapt­ing Glazes” in the text.

De Boos DB3Cone 6

Whiting...........................2 tbsp - 2 tspNepheline Syenite ... %cup + 1 tsp

Ball Clay..................................... 2 tbspCedar Heights Redart Clay .. 2 tbsp

Red Iron Oxide............................. 1 tspThe minus sign is not a typo. To achieve the smaller amount of whiting, 2 tsp were taken away from the 2 tbsp. Caramel in color. Works well on leather-hard clay.These glazes are wonderful in blends or in double application.

MOPE 2Cone 6

Frit 3134 (Ferro) .... 1/4cup + 1 tbspKaolin.........................Vi cup + 2 tbspFlint.............................................1 tbspTin oxide.....................................1 tbspA lovely majolica-type glaze. Adapted from a Hobart Cowles glaze.

Behrens WhiteCone 6

Whiting......Vz cup + 2 tbsp +1/4 tspZinc Oxide ... 1A cup + 1tbsp + 2 tspPotash Feldspar............. 1 ½ cupsKaolin........1/2 cup + 2 tbsp +1/2 tspFlint........................2 tbsp + Vz tspStony white. Particularly nice with cobalt deco­ration. Modified from a Cone 4 Richard Behrens by-volume glaze that has been in my notebooks for ages.

Mediterranean GreenCone 6

Strontium Carbonate...........1 tbspKaolin.................................. 1 tbspZinc Oxide............................1 tspPotash Feldspar..................½ cupGerstley Borate................... 2 tbspFlint..................................... 2 tbspCopper Carbonate............. 1 Vz tspRutile....................................1 tspDark, almost metallic green. From Lee Arts Center, Arlington, VA.

Carol’s GreenCone 6

Dolomite..............................1 tbspGerstley Borate...................1 tbspPotash Feldspar..................¾ cupZinc Oxide........................... 1 tspKaolin..................................1 tbspFlint..................................... 1 tbspCopper Carbonate...............2 tspMedium, smooth-looking green. Very similar green glazes no matter how measured out. From Lee Arts Center, Arlington, VA.

CllCone 6

Dolomite.............................. Vi cupFrit 3195 (Ferro)................. Va cupClay.....................................1/4 cupFlint.....................................1/4 cupNot illustrated as it photographs transparent. An almost-clear glaze that becomes silky white when opacified and takes colorants well, with the expected magnesium modifications.My oldest “home-made” glaze.Anyone can memorize this one!

BB ClearCone 6

Frit 3124 (Ferro)............. 4½ cupsClay......................................1 cupFlint....................................1 cup*Add: Bentonite as neededMy basic transparent. I have used it on all sorts of bodies, always with success. Boron con­tent enough to create expected boron effects.

* Scant, do not pack.

White SlipPotash Feldspar................... 1 cupBall Clay.......................... 13 cupsKaolin................................3 cupsFlint................................... 2 cupsZirconium Opacifier.............. 1 cupBentonite (dry)......................1 cupI use XX Sagger clay for the ball clay as it is white in the raw state. Have used Tenn. 10, which is very light in color.

Robin Hopper SlipFeldspar...............................1 cupBall Clay............................ 8 cupsKaolin...................................1 cupFlint...................................... 1 cupThis recipe has been adapted. I add 1/2 cup zirconium opacifier. I have found no difference between types of spar used.

Lili Krakowski is a professional potter residing in Constableville, New York. She teaches pottery at the Gibbes Museum of Art in Charleston, South Carolina, during the winter months.

Pottery Making illustrated 37

38 Summer 1999

Pottery Making illustrated 39

Here are two lightweight portable kilns built for clients. Note that one has a fire chamber that was built with two layers of 8-pound-density fiber blanket. The larger kiln unit sits on a firebrick ring, the other smaller kiln was made to sit on a firebrick firing chamber that the client planned to build. The construction of the firebrick ring and the firing chamber will be described in Part II.

ilns made with a refractory fiber material, such as Kaowool (a fiber blanket), can have many different shapes and made with different bracing materials—only your imagination, skill, budget and/or the availability of materials limits how and what you make. I’ve constructed several fiber kilns and here’s one method I’ve found that makes a durable,

inexpensive and lightweight kiln for any potter intending to explore the firing range from raku to Cone 6. Since the method is lengthy, I’ve divided it into two parts. Part I deals with building the domed-top portion and Part II (in the Fall 1999 issue) describes the method for building the base and fire ring.

SpecificationsThe cylinder-type kiln is both economical and easy

to construct. The top portion discussed here in Part I measures 22 inches in diameter and is 23 inches high. These measurements not only make the best use of com­monly available 24-inch-wide fiber blanket, but they also allow for compression of the fiber during construction and shrinkage during the first few firings.

Why a dome? Many ceramic fiber kilns made with flat tops sag with continuous use, so using a dome shape for the top allows you to fire the kiln many times with­out any sign of wear.

Larger-sized kilns are not recommended for the first- time builder as they would probably require a forced- air, power burner. A small kiln, as described in this ar­ticle, will fire easily with one venturi-type burner, such as the cast-iron type featuring a flame retention one- piece design rated at 75,000+ Btus operating on pro­pane.

Health RisksWhen working with welded wire mesh, always wear

protective leather gloves and safety glasses. The welded wire mesh can have extremely sharp edges along the cut-wire ends and very serious cuts can result. Snipping the ends of wires can flip the cut pieces across the room, posing an eye danger, so safety glasses are a must.

Operating a gas kiln is dangerous, so take all safety precautions necessary. For safety information, check with your local gas supplier or fire department.

The fiber in fiber blankets should not be inhaled.Work with the fiber blanket outdoors and always wear a NIOSH-approved respirator when working with this material. There is an ongoing health concern with ex­cessive exposure to airborne refractory ceramic fiber (RCF) material. While some suggest lining the outer surface with heavy-weight aluminum foil as an inex­pensive way of reducing RCF exposure, I feel that alu­minum foil has a limited life and will have to be re­placed as it slowly corrodes. I recommend coating the fiber with a thin inexpensive refractory coating (see recipe). This coating does not have to be thick, just enough to seal any loose fibers on the surface. Coatings may be reapplied as the kiln ages with use. Apply this coating as the last step of your construction.

40 Summer 1999

by Don Adamaitis

K

Materials

• Welded wire mesh: 2 or 3 feet wide by 9 feet long; lxl-inch gal­vanized 14-gauge or heavier (but not lighter). Purchasing 3-foot- wide mesh allows you to cut a 24- inch piece for the domed-top kiln and leaves you with a 12-inch- wide piece for a bracing the wall of the firing chamber to be built in Part II. While lx2-inch mesh would be suitable for the wall of the chamber, the top must be con­structed using the lxl-inch mesh.

• Fiber blanket: 2 feet wide by 14 feet long (I used Kaowool). Note: You need 8 feet of blanket for Part I and 6 feet for Part II of this kiln.I usually use 6 pound per cubic foot (PPCF), mainly because of the weight, price and operating temperatures when used as a raku kiln. I would use 8 PPCF if the client requested it. I also recom­mend that you use 1-inch-thick material because the 2-inch-thick material is too soft and takes up too much of the interior volume of the kiln.

• 3 or 4 feet of stainless steel wire, 308 SS, a common MIG welding wire (found at Home Depot) will work if using “stud-type fasten­ers.” You could also use a 316 SS MIG wire, which is much more corrosion resistant, but is only available from welding gas supply stores. The MIG welding wire is fine if you intend to use the kiln mainly for raku and occasional Cone 6 firings. Use 20-gauge nichrome (2250°F) or Kanthal (2330°F) wire you are using “but­ton-type fasteners” that will have wire exposed to the internal flame or if you intend to use the kiln mainly for Cone 6 firings.

• High-temperature coating (see Recipe).

• Ceramic studs (see Making Ceramic Studs).

• Heavy wire: 160 inches of ½- to ½-inch galvanized wire, com­monly used for the bracing of the bottom of chainlink fences.Note: You’ll need 80 inches each for each Part I and Part II of the kiln.

ToolsThe minimum materials required to builda fiber kiln can be purchased at mostgood hardware or farm-supply stores:• Dust mask, to be worn when working

with the fiber blanket• Adjustable pliers• Wire-cutting pliers• Common pliers• 2-pound rubber mallet• Sharp knife (a serrated bread knife or

similar) or shop scissors• Tape measure• Black felt-tip marking pen• Masking or electrician tape• Protective rubber gloves for working

with the sodium silicate/refractory ce­ment mixture.

• Leather-palmed gloves for working with the wire fabric.

Making Ceramic StudsYou’ll need about 60 ceramic holding studs to secure the fiber blanket to the frame. Make the studs ahead of time from Cone 10 porcelain clay mixed with 20+ mesh lone grog, and fire to a high bisque (Cone 02). The studs are approximately2 inches in diameter (when green). Mak­ing and using a production bisque or plas­ter press mold and cutting out disks with a cookie cutter, assure consistent-size studs. Don’t forget to drill a hole for the Nichrome wire through the raised-back portion of the stud before bisque firing.

Dry mix the ingredients well, then mix the sodium silicate and water and add it to the dry materials. Mix thoroughly to a cream consistency.

To this mixture, blend in one 32-oz. container of gray high-temperature refractory Furnace& Retort Cement. Grant Wilson is one brand sold in most hardware stores, another brand is Master Plumber High Temperature Fur­nace Cement, distributed by TruServ, Chi­cago, IL 60631-3505. Sold through True Value hardware stores.

Thin the final mixture with water until the de­sired consistency is achieved. Yield is about1 gallon, which is more than you need, so save the extra for the fabrication of Part II.

Health Warning: Refractory Ceramic Fiber (RCF) materials are cur­rently under study as a human carcinogen that may share characteristics similar to asbestos. RCF materials are usually contaminated with crystalline silica, a known human carcinogen, and the agent that also causes silicosis. Airborne fiber dust is an extreme health hazard. Before attempting to handle these materials, contact your refractory supplier for the Material Safety Data Sheet and recommended handling procedures for any materials you plan to use. Use of NIOSH-approved respirator, local pickup ventilation, protective clothing, stringent personal hygiene and extensive site cleanup are mandatory to minimizing risks. Ed.

High-Temperature Coating Recipe

Dolomite............................ 200 grTalc.................................... 200Alumina Hydrate................ 200Lincoln 60 Fireclay.............400

1000 grAdd:Sodium Silicate..................3 cupsWater................................. 1 cupFurnace & Retort Cement ...32 oz

Pottery Making illustrated 41

Construction

Step 1. Prepare the materials*From the 9-foot length of galvanized welded wire

mesh, cut a 24-inch-square piece. (Remember: Measure twice, cut once!) This piece must be 2 inches greater than the outside diameter of the kiln; that is, to make a 22-inch diameter kiln, you’ll need a piece that measures 24x24 inches. The remaining piece should be at least the circumfer­ence plus 3 inches of the intended kiln to allow for joint overlapping. For the kiln described in this article, this would be 75 inches long.

Cut a 24x24-inch square piece of the fiber blanket for the dome insulation. For the fire chamber wall, you’ll need a piece that’s 6 inches greater than the circumfer­ence of the kiln to allow for overlap at the joint seam and firing shrinkage.Step 2. Form the dome

Take a piece of tape and mark the center of the square wire mesh top (fig. 1), then draw a 22-inch-diameter circle with the aid of a piece of string and a felt-tip marker. Mark various points of the circle’s circumference with pieces of tape. Start forming the dome top by placing this wire mesh over a metal trash can .With a rubber mallet, strike the mesh starting from the center and move outward in a spiral pat­tern toward the rim of the trash can (fig. 2).

Once you have a rough dome shape, place the disk on a smooth hard surface. Using the rubber mallet, strike the outer corner edge of the piece to flatten the outer edge surface (fig. 3). Continue this process of working the dome by turning it on its center, which is marked by masking tape. Carefully watch your progress. Maintain light, even blows to form an even, circular dome. Periodically set the worked piece on its edge and “eyeball” its shape to assure that it is a smooth, not oblong, curved arc.Step 3. Form the cylinder

Take the 76-inch length of the galvanized welded wire mesh and cut off the horizontal wires at the top and bot­tom with wire cutters.This leaves 1-inch vertical wires ex­tending from the top and bottom of the mesh. Next, cut out the first inch of vertical wires at the beginning and end of this length so you will have 1-inch wires extending from all sides of the mesh.

Align the horizontal wires of the mesh so that you have an overlap joint of two complete squares of wire, then bend the outer end-wires inside through the mesh and the in­side overlapping end-wires outward through horizontal wires.This should form a double gripping weave with a 2- square overlap, securely locking the mesh cylinder.

With the needle-nose pliers, bend and twist these wires so the sharp ends are pointed inward to prevent injury. Lay the kiln frame on its side on a solid surface, and hammer this seam flat with the rubber mallet to create a flat, inter­locking, 1-inch overlapped joint. Note: Figure 4 shows a 1-square overlap, but I have since updated the construction to form a more stable joint with the 2-square overlap.

Figure 1

On the piece for the dome top of the kiln, carefully flatten the wire mesh and find the center. With a string-type com­pass, mark the circumference with a felt-tip marker and mark the center and corner portions with pieces of tape.

Figure 2

Over the opening of a metal trash can, stretch the wire mesh by striking with a rubber mallet from the center, spi- raling outwards. Turn the wire mesh as you work it and follow the marked circle of the circumference. By using a moderate force and constant turning, the wire mesh will begin to stretch and take a dome-shape within the cir­cumference marked line. Wear gloves while handling the wire mesh, as the cut ends are very sharp and can cause severe cuts.

Figure 3

Periodically lay the wire on a flat surface and flatten the edges along the marked circumference of the dome top. You should eyeball the curvature of the dome shape. By lightly tapping any high or irregular points on the arc, you will end up with a smooth, even dome for your kiln.

42 Summer 1999

Figure 4

The kiln frame is set up, with all pieces in place to check for fit before permanent attachment. Make any adjustments or changes at this time. Note the 1 -inch overlap joining of the kiln frame cylinder and the location of the wire lift handles.

Figure 5

Start attaching the top dome by bending the protruding vertical wires outward, over the nearest dome wires and back into the cylinder. Not all vertical wires will match a horizontal dome wire; do as many as possible.

Figure 6

With the wire cutters, cut around the corners of the dome piece so the wires extend 1 inch past the kiln frame cylin­der. Do this so you have as many clean, nonattached wires as possible extending over the edge. Bend these wires over the top horizontal wire of the cylinder so that all ends are pointed inward and crushed tight, securing the dome top to the frame cylinder. Trim off any wires that do not match.

Step 4. Place the domePlace the square dome top on the cylinder so you have

the 1-inch wires protruding through the dome piece (fig. 4). Now bend out several wires to temporarily lock the dome top in place to check the fit. Adjust to make sure you have a true circle. At the bottom of the cylinder, bend2 out of every 3 bottom vertical wires to a 90° angle (this will support the reinforcement hoop). Leave every third vertical wire at the bottom straight. Lay in the ½-inch wire hoop at this time. Cut it so you have a 3- to 4-inch overlap.Step 5. Add handles

Now decide where you wish to locate the hardware for lifting the kiln. If using U-bolts or garage-door handles, install them with galvanized nuts, bolts and washers.Note: I recommend that on a small kiln (under 18 inches in diameter) the handles be placed on the sides about ¾ of the way up from the base. On larger kilns, I recommend that U-bolts or ½-inch wire handles be used and placed on the top near the outer edge, which provides mini­mum structural stress to the kiln chamber during lifting.Step 6. Attach the dome

The domed top should now be on the cylinder, so you have a good fit with the extruding wires. Follow the marked circle as close as possible. Take the vertical wires of the cyl­inder that protrude through the dome top and bend them over a neighboring dome wire and point inward (fig. 5). Any vertical wires that cannot be bent over neighboring dome wires are bent inward and clipped short.Step 7. Trim the corners

With the wire cutters, round off the top by trimming the corners of the domed top so there is 1 inch of wire extending past the kiln frame cylinder. Do this so you have as many clean non-attached wires as possible extending over the edge. Bend these wires over the top horizontal wire of the cylinder. All ends should point inward and be crushed tight (fig. 6).

SOURCES• Welded wire mesh

Davis Wire Corp., 31775 Hayman St., Hayward, CA 94544 (write for dealers/stores in your area) or http://www.daviswire.com Wichita Feed and Hardware, 6089 S.E. Johnson Creek Blvd., Portland, OR 97206. Phone (503) 775-6767 or fax (503) 775-2150.

• Nichrome wireMALIN Co., 5400 Smith Rd., Brookpark, OH 44142

Pottery Making illustrated 43

Step 8. Reinforce the cylinderWith pliers, bend the bottom vertical wires of the cylin­

der over the ½- or ½-inch wire hoop, securing it in place (fig. 7). Leave every third wire straight.These straight wires provide support for the kiln and allow the fiber blanket to make a seal with the firebrick of the firing chamber with­out being crushed.

Before proceeding, carefully inspect your work. Make sure all wires are secure, tightly crushed and tucked in with the sharp ends pointed inward. The frame should be solid and not flex when lifted by the handles. Correct any faults at this time (fig. 8).

Step 9. Lining the dome top*Place the piece of the fabric that will be. the top on a flat

surface. Use a piece of string as a compass and mark a 24- inch circle with the black felt-tipped marker. This circle should be at least 1 inch greater than the kiln diameter. With the pen, mark the center clearly. Cut the fiber blanket with metal snips. [Note: You can reduce the amount of airborne fiber particles as you work by keeping the fiber blanket damp; mist with a spray bottle. Ed.]

Now take the dome piece of fiber blanket and work it inside the metal chamber. Match the center point you made with the felt marker to the center of the piece of tape on the dome top. Once in place and centered, press it firmly against the dome top and tuck in the edges of the fiber blanket so they are butted to the wall of the kiln frame.

Figure 7

Attach a wire hoop to the bottom of the kiln cylinder to provide rigidity to the cylinder. Leave every third wire straight to provide support legs for the cylinder and prevent crushing the bottom fiber blanket seal.

Figure 8

This is now a lightweight, rigid kiln frame ready for the attachment of the fiber blanket fiber.

Figure 9

With a loop of wire through the ceramic stud, you will find it easier to install them where you want by penetrating the fiber blanket first with a sharpened tube. Insert the wire through the tube and then remove the tube, leaving the wires protruding through the fiber blanket. Add a little dab of the refractory coat­ing to the back of the ceramic stud just before attachment to the kiln.

Figure 10

Take one of the extruding wires and move it under a frame wire so that the two wires are straddling the frame wire. Pull taut with a pair of pliers and give the wires several twists. Clip off the twisted Nichrome to 1 inch in length and tuck wire back into the fiber blanket.

* WARNINGTo reduce RCF health risks, wear a NIOSH-approved respirator

while working with all refractory ceramic fiber materials!

44 Summer 1999

Step 10. Locating the flueI normally cut the opening for the flue mid-point be­

tween the center and the edge of the domed top. This al­lows a stud to be placed in the center of the domed top and also allows the kiln to be lifted by a wire pulley setup if so desired without burning off the wire. Additionally, it also allows a viewing position of pots inside the kiln if no peep­hole is installed.The flue opening should be about 5 inches square. Mark where you wish to place the flue hole with a pen and also mark the location points for the supporting ceramic studs. Note: Do not cut the flue hole at this time.Step 11. Attach fiber blanket to the dome*

I normally set the studs 4 to 5 inches apart on center, depending on the size of the kiln. The top of the kiln, because it is domed and has a cemented flue opening, re­quires very few studs; and the distance between them de­pends on the diameter of the kiln. Attach the fiber blanket to the top of the kiln frame with the ceramic studs by pushing the Nichrome or stainless steel wire through the fiber blanket dome top so the ends of the wires straddle a galvanized dome mesh wire. This task is easy if you use a piece of ^6-inch metal tubing commonly sold at hobby stores. Force the tubing through the fiber blanket from the outside of the kiln. Insert the wire ends of the stud into the tubing and retract the tubing (see fig. 9). With the pliers take one of the wires and move it under a dome wire so the two wires straddle a dome wire. Now pull and twist the wires (see fig. 10).Trim the twisted wires to about 1 inch and fold the end of the wires back into the fiber blanket. Do this after each stud is installed to prevent puncture wounds by the sharp wire ends. As you install the holding studs, put a dab of the refractory coating on the “nub” where the wire is attached to the stud.Step 12. Form the flue*

To form the flue opening in the area you marked out, snip out the wires of the dome mesh to form a square flue space measuring 5 inches per side. Cut an “X” through the fiber blanket, stopping about 1 inch short of the wire mesh corners. Lift the opening in the fiber blanket from the in­side outward. Add a thin layer of refractory cement around the outside of the flue opening. Wearing protective rubber gloves, pull and stretch the fiber blanket that has been damp­ened with refractory cement, enlarging the hole slowly. Continue stretching and applying refractory cement as needed, working the fiber blanket into a puttylike consis­tency. Roll and stretch the fiber blanket, enlarging the hole and moving the fiber blanket out of the flue opening and onto the domed top. This will take some time, but it will gradually form into a cuff around the flue. Fiber blanket is not made up of interwoven fibers, but compressed short fibers. With a small amount of refractory cement, cement this cuff to the dome top. If desired, add small stitches of Nichrome wire to aid holding the fiber blanket in place. By forming this cuff of fiber blanket around the flue open­ing, you will prevent excessive corrosion of the flue open­ing wires by the acid exhaust gases during firings. It is best to wait until the refractory cement is dried before pro­ceeding to the placement of the refractory fabric in the chamber frame.

Step 13. Attach fiber blanket to the cylinder*Measure the circumference of the kiln with the tape

measure or piece of string and add 6 inches to the result. Roll out the refractory fiber blanket and mark this length. To begin to make the lap joint, measure 2½ inches from one end and with a sharp knife cut halfway through the thickness of the fiber blanket. Remove this half thickness from the end of the fiber blanket fabric.

Starting with the end where you made the lap joint notch, place the fiber blanket inside the kiln chamber, cut portion facing inward. Start at the center of the lap joint and evenly mark the ceramic stud column locations. Press the fiber blanket tightly against the fiber blanket in the dome top. Work the fiber blanket around the inside of the chamber so it compresses. The length will be longer than necessary. This will be fitted at the addition of the last col­umn of studs. Start installing the ceramic stud fasteners one column beyond the marked column of the lap joint. Again tuck the twisted wires of the stud fasteners back into the fiber blanket insulation.

When you have two columns of studs left to put in, including the overlap section, place the fiber blanket over the lap joint and mark the joint section. Leave about ½- inch excess in length with the knife or scissors, cut the inside of the overlap less than half way through the fabric, remove this fiber blanket. Compress the two lap ends to­gether so as to form a tight overlapping joint that lays flat. Finish installing the ceramic stud fasteners and install the last column of ceramic stud fasteners through both thick­ness of the fiber blanket lap joint. No refractory cement should be required.Step 14. Finish the bottom edge*

The fiber blanket on the inside of the kiln chamber should extend about 1 inch beyond the bottom of the last horizontal wire of the chamber. If it doesn’t, you’ll have to reduce the height of the chamber by removing the re­quired length of wire mesh so the extending vertical wires on the bottom of the kiln can pierce the fold of the cuff. Compress the cuff against the wire chamber and secure it in place with short loops of Nichrome wire.Tuck the twisted wire ends back into the fiber blanket. The vertical wire ends protruding beyond the fiber blanket cuff will act as support legs but still make a tight seal between the kiln and the firing chamber (see photo on p. 40).Step 15. Coat the kiln*

Use a venturi-type spray gun or a paint brush to coat the outer surface of the kiln with a thinned high-tempera- ture refractory mixture. Allow the coating to dry before firing the kiln. Apply another coat after the first firing or as the kiln ages with use. The refractory coating may also be used on the inside of the kiln and firing chamber, but it should be a single, thinly sprayed coat. Too thick of a coat­ing on the inside can cause cracking of the coating and particles could drop on the glazed ware.

To add a little color, you can demonstrate your artistic talents once the coating has dried and fired, by spraying the outside of the kiln with a high-temperature engine enamel (1500°F type).Don Adamaitis will describe building the base and fire ring in Part II, coming in the Fall 1999 issue of Pottery Making Illustrated.

Pottery Making illustrated 45

hile it’s undoubtedly best to have a human instructor when learning the basic tech­niques of pottery-making, everyone involved

with clay can benefit from a few good books.There are so many aspects of pottery that require detailed techni­cal information that no one person can know or teach everything. Even the potter with decades of experi­ence can be stumped by a new problem, and the stu­dent just beginning to delve into the mysteries of clay can find the depth of the subject overwhelming.

Fortunately, there are now many fine books dealing with a variety of subjects related to pottery making, ranging from how-to manuals for beginners to techni­cal tomes dealing with arcane processes and problems. Anyone who has picked up an old pottery book from the 1970s in a used book store is in for a pleasant sur­prise when opening some of the books now available. The black-and-white drawings and photographs of lumpy brown pots that made older how-to books in­

formative, but often hardly inspiring, have been replaced by vibrant and exciting color photographs of pottery and processes.

There are books dealing with techniques for shaping wet clay or explaining glaze chemistry; books on work­ing with a specific type of clay, kiln or process; and books that touch on the whole range of possibilities. Any pottery teacher will find it an enormous benefit to have a library of books available to students who have specific questions or goals and any serious stu­dent would be well-advised to invest in a few good books. Here are six informative, thought-provoking and inspirational titles to consider.These are general-inter- est books that the beginning to intermediate potter will find useful. Whether you’re struggling with a par­ticular problem, interested in making a specific type of pottery, or looking for ideas, these are titles I find my­self frequently recommending or lending to students and others.

Tony Birks - The Complete Potter’s Companion Rev. Ed.New York: Bulfinch Press, 1998Based on The Potter’s Companion, first published in 1974, this book is well illustrated in color and is suitable for beginning pottery students. Birks begins by explaining what clay is and discussing the various types of clay, then covers forming clay on the wheel and by hand; glazing, including a brief discussion of glaze materials and a few recipes; decorating; and several firing methods. None of these subjects is covered exhaustively or in great technical detail, but enough to answer basic ques­tions and point the student in the right direction for continued experimentation. The book ends with a brief section on setting up a home studio, a glossary and a list of suppliers.

Joaquim Chavarria - The Big Book of CeramicsNew York: Watson-Guptill, 1994

This book is so lavishly illustrated with color photographs of pottery, pottery-making processes, tools and materials that it looks like a Time/Life book. It’s intended for adults, and includes fairly technical information about glaze formulation and firing, but the pic­torial content appeals to even quite young children. It isn’t the most in-depth of texts, but it’s an eye-catching introduction to the craft.

46 Summer 1999

w

Richard Zakin - Ceramics: Mastering the Craftlola, Wl: Krause Publications, 1990The title is a bit hyperbolic; it takes more than a book to make one a “master of the craft.” However, the book will help you appreciate the breadth and depth of the craft today. Zakin discusses every aspect of pottery and ceramic art, from analysis of materials to forming tech­niques, enriching each topic with essays and photographs of work by artists working in a wide range of styles. This is an informative text packed with technical information as well as discus­sion of aesthetic concerns.

Peter Cosentino - The Encyclopedia of Pottery TechniquesPhiladelphia, PA: Running Press, 1990

Using many color photographs of forming and decorating techniques, and of completed work, this book illustrates an in-depth exploration of topics from the basic (centering clay on the wheel) to the esoteric, such as designing, which is defined by the author as “the development of individual ideas taken from a particular starting point through to the completed work.” A section

titled “Themes” deals with broader topics, such as “Functional and Domestic Pottery” and “Sculptural and Abstract Forms,” and might be particularly useful to a teacher seeking to expose students to the range of possibilities inherent in clay.

Robert Fournier - Illustrated Dictionary of Practical Potterylola, Wl: Krause Publications, 1992

This book is primarily concerned with the historical, aesthetic and practical aspects of pot­tery making. It’s accurately titled a dictionary (rather than an encyclopedia) because it does not cover any subject exhaustively.The book is useful to answer questions about terms, tools and techniques, though a reader may need to find another work to understand topics in depth. It is a wonderful book to keep around to browse for ideas and inspiration.

Frank & Janet Hamer - The Potter’s Dictionary of Materials and TechniquesPhiladelphia, PA: University of Pennsylvania Press, 4th ed., 1997

Just as the title would indicate, this book is an alphabetical listing of almost every material, form, term and process used in or relating to pottery making. Well illustrated in black-and-white, with a few gorgeous color plates, some of the definitions are highly technical. Under manganese oxide, for ex­ample, are diagrams of the molecule in different forms, and recipes using the material; while the entry for eutectic mixture takes up most of three pages and includes several graphs. Other entries are likely to be of great interest to the student, such as that for lids, which includes several nice drawings of lid and lid-seating cross sections.

A potter for 20 years, Sumi von Dassow teaches pottery at the Washington Heights Center for the Traditional Arts in Lakewood, Colorado, and is a frequent contributor to Pottery Making Illustrated. Visit her web site at http://www.well.com/~sumi for more information.Pottery Making illustrated 47

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