7/22/2019 Selva -Expert'sTips, Casting and Decorating Ceramic Materials

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For Reliefs and FiguresSELVA Casting Material »Artelin«

Properties: Low cost, ceramic-based.

Usa ge: For making reliefs, figures and shaped objects .

Proces sing: Mix 3 parts of Artelin to 1 partof wa ter. S olidifies a nd ha rdens within30 min. The ca stings ca n be removed fromthe mould immediately and then be painted

or finished, e.g ., remaining edg es c an befiled or sanded.

Pa inting: Before painting it is a dvisa ble toprime the surface with a sea ler. All pa ints

and lacquers can then be applied. Artelincan be shaded before casting: Use Univer-

sa l Toner Conc entrate in sha des terra c ottaand da rk grey along with Cas ting MaterialTone r.

Finishing: In order to make the pa inted ca sting w eather-proof, a final coa t of UV

Lacquer, 3-D Crystal Lacquer or Cold Glazing has to be a pplied.

For Weather-Resistant CastingsArtestone

Properties: Extra-hard a nd hydrophobic

(wa terproo f) cera mic ca sting ma terial. Veryad vantag eous: The cured a nd hardened ca s tings due not absorb moisture, which isabsolutely necessary when casting

 weather-resistant figures. Artestone ismodified on a phosphate base in combina-tion with natural gypsum, and is considereda non-toxic a nd physiologically sa fe mater-ial. It is a preferred ma terial in scho ols,

training and rehabilitation centres as well asbeing used by professional artists.

Usa ge: Rock-hard, wea therproof objectssuch as house Nos. and name plaques, decorations and garden statues, birdbaths,small fountains, etc.

Proces sing: 4 parts of Artestone to 1 part of

wa ter. Artestone beco mes solid a nd rock-hard w ithin 30 min. Artestone ca stingsshould b e wo rked o n and finished immedi-ately after removal from the mould since af-

terwards they b ecome extremely hard.Sha ding/Decorating: Artestone c an b e

 sha ded with Universa l Toner Co ncentra te orCa sting Mate ria l Toner in terra co tta or da rkgrey/blac k. It is po ss ible to not o nly thesha de c as ting ma terial with a s ingle colour

but also to give it a ma rble finish to createproducts with unusual finishes.

Finishing: A co a t of 3-D Lac q uer or Co ldGlazing is required only if an effect of visualdepth is to b e ac hieved.

Casting withSingle-Part MouldsThe mould must be stea died a nd levelled.Larger moulds should be supported aroundthe edges , e. g., w ith wood en strips. Any

hollow spa ces underneath the mouldshould be filled in with newspapers. Evenbetter is wet sand so that the mould doesnot sa g under the weight of the ca sting

ma terial. This is pa rticula rly importa nt w ithclock dials since they sho uld not be to othick. Large, flat moulds,e.g . chessboa rds, shouldbe fastened to the work

surface with double-sidedtape since otherwise themould may not lie flat. Afterpouring the liquid ma ss into

the mould, the latter shouldbe shaken to let air bubblesrise to the top where theyca n be picked off with atoothpick or a fine wire. If

an even s urface is notachieved on its own, rockthe mould b ac k and forth a bit. Now lea vethe ca sting to c ure unless a hange r or

a da p ter has to be a dded . To d o this, w aituntil the mass has hardened to a firm con-sistency before pushing in the part. Stuff

a d a pters with paper to keep ca sting ma ter-ial from entering their bores. After a pprox.

20 min, the c as ting ma terial has hardenedand wa rmed up noticea bly. The bes t time to take the c as t from the mo uld is a pprox. 30to 35 min after ca sting. P lac e large mouldson their backs, loosen the ed ges and pull

the mo uld off the c as ting. With s ma ller, highly detailed moulds, it ma y be necess aryto pour some w ater mixed w ith a drop ofdetergent down the loosened edge s. The

ca s ting w ill then »sw im«in the mo uld ma k-ing it easier to remove.

Caution: So me moulds a re not very sturdyand may break if kinked or bent!

With small castings, it is best to let them fall

into the open palm or help along by hittingthe mould a ga inst the pa lm so that – due to

its own weight – the casting will be releasedfrom the mould.

Casting with Two-Part Moulds(so-ca lled »3-D moulds «)

The first half of the mo uld is fi lled the s a meas a single-part mould. Let this c as t hardenand then take it from the mould. Pour thesec ond half and fit the first half to the still

pasty second casting. If a hanger is

 needed, fit a wire loop betweenthe two halves. Small gaps and holes along

the sea ms c an later be filled w ith fresh c as tingmaterial. With small castings, it may be easierto level their bac ks with sandpa per andthen bond them together with white glue.

Casting Figuresin Latex MouldsSus pend the rubb er-likemould upside do wn.

These m oulds usua lly have a ba se w ith across s ection that is larger than the fi gureitself. The mould ca n be s uspend ed b y this

ba se through a cut-out in a hea vy piece o fcardboard. Glasses, pots, pitchers or boxescan be used as supports for the cardboardwith mould. Very large mo ulds usua lly comewith their own support to prevent the con -

siderab le w eight of the c as ting ma terialfrom expanding the mould. Self-made latexmoulds c an be imbedd ed in damp sa nd. Fillapprox. half of the mould with casting

material, knead it to remove any air pockets– e.g . in nos es –, then fill the mould to thetop and leave it hang.

Pleas e note: The ba se is usually not part of

the figure and should not be filled. Excep-tion: Chess men. The ca st ca n be ta ken fromthe mould after 30 min at the earliest, betteryet a fter 45 min. The ela st ic mould is turnedinside o ut to p ull it from the ca st.

Very important: To fa cilita te remo va l, theoutside o f the mould ha s to be c overedwith soapsuds to make it slippery.

Critica l castings, s uch a s fi gures with nar-

row parts (e.g. a thin neck), are prone tobreak d uring removal from the m ould. It isbest to pull the mould off to the criticalpoint and then hold bo th the cas ting a nd

the mo uld a t their fa r ends. The mo uld’selas ticity will now help to pull off the mould– possibly with a strong wrenching motion.

Cast ing and Decorat ing Ceram ic M ater ia ls 

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SELVAE x p  e r t  ’

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Description Page

Protective lacquers 81

Casting materials and supplies 109

Moulds 109

Paints 104–106

Paintbrushes 93+104

These products from the

SELVA Programme help youto do a professional job:

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Taking Care of MouldsAfter casting, remnants o f ca sting materialmust be removed from the mould. P leas edo no t use sha rp or hard tools, which couldinjure the surface. Use fingernails or

 woo den too thpicks. S tore the moulds levelso tha t they do not lose their shape. S pe-cial care or treatment with release agents isnot necessary.Latex moulds should b e c leaned inside and

out b y rinsing them under running w a ter.Turn them right side o ut, let them d ry, dus tthem with mould powder and store them ina cool, dark place. Latex moulds become

brittle if subjected to daylight or – worse yet– direct sunlight for long er periods of time.Also important: Avoid any contact withgreasy or fatty s ubstanc es (skin cream)!

Finishing The CastingsAfter they a re taken from the mould, the stilldamp castings have not reach their finalhardness. They ca n ea sily be worked on,e.g., scraping them with an old knife bladeto chamfer the edges. If a file or a drill is

used, they should carefully be cleaned offafterwards o r they will rust. Sa ndpape r canonly be used after the casting is co mpletelydry. For drying, the castings s hould be po-

sitioned so that the water can evaporate onall sides. If the c as tings are to b e pa intedwith water-ba sed paints, this w ork ca n besta rted approx. one hour after taking thecasting from the mould. If solvent-based

lac quers or paints a re used, the ca stingshave to be absolutely dry (overnight on aradiator).

Paints and PatinasAny pa int, such a s w ater-ba se, a crylic o r

ca sein paints or simply a qua relle o r wa tercolours, but a lso e namel and o il paints, ca nbe used with good results.

Please note: Felt-tip paints tend to run and

have a milky appea rance . Wa ter coloursshould be protected with clear lacquer. Forpa tina fi nishes , se e the S ELVA Expert’s TipNo. 466-451-700!

Bonding Castings?Yes, ca stings c an be b onded a fter they arecompletely dry! Epoxy and contact cements aswell as wood glues can be used.

Colouring CastingsWatercoloursBeautiful results can be achieved with wa tercolours or aq uarelle pa ints. Thesepaints are of very low visco sity a nd tend togather in the crevices of the surface struc-

ture. This will give a n a tural pa tina effec t:The reces ses will be da rker, the top s urfacewill be lighter. Thus, t he fea thers o f a b ird o r

the coat of a furry animal will have a moreplas tic a ppearanc e than if a pa int with a

more even coverag e is used. P leas e re-me mber that the paints taken directly fromthe ir con ta iners a re »raw ma te ria ls«. Try toac hieve a multitude of s hade s by mixing.

The spring pas ture ha s its freshne ss be-ca use of a drop of yellow or orange in itsgreen; the bush or tree contrasts with thegreen if a little ochre or brown is mixed in;and for the woods along the edge of the

horizon a little black or blue is added to thegreen. Always paint from light to dark shad es – it is a lwa ys poss ible to da rken anarea later on, but hard to lighten a sha de.

Wate rcolours s hould be protec ted w ith a clear lac quer. It can be applied a s s pray orwith a brush. Mat lacquers – well shaken orstirred – are best suited. Areas such as eyes, shoes or dog’s noses can later be fin-

ished with a g loss y lacq uer.Please note: Apply ornamentations withgold bronze a t the very end or else they bec ome dull when lac q uered. Wate rcolour

go lds a nd s ilvers a re not very brillia nt.

Water-based Paints(Acrylic, casein, peasant-style paints)

Here, too, the colours should be mixed sothat they d o not appea r too shrill. Do notmix or dilute in the original paint container.Take a sma ll quantity of eac h shad e a nd

mix it in, e. g., a bo ttle ca p. If the pa ints arekept pure and undiluted in their closed con-

ta iners, they will las t for a very long time.Mixed co lours in a bottle cap ca n be keptovernight in a tightly closed butter dish or

simila r conta iner, po ss ibly tog ether with a

da mp spong e. G enerally, mat paints arebetter suited than glossy ones . Areas thatshould be glossy can later be coated with

clear lacquer. Always clean paintbrushesand other tools immediately after use. Dur-ing longer paint jobs, clean the brushes inbetween to keep the paints from hardeningand settling in the b ristles. Never lea ve

pa intbrushes sta nding in wate r! They w illdeform and will no longer be usable for exactpainting. Clean small lacquer brushes withthinner/brush clea ner or na il po lish remo ver.

Lacquers/Oil Paintsare very durable, but not as popular with

hobbyists since they are not as ea sy to mixas wa ter-based paints. Also, they ha ve longdrying times a nd so lvents a re needed forcleaning pa intbrushes and tools. A garden

figure that is to survive outdoors for a few years is best deco rated with enamel or oilpaints. Do not coa t such pa ints with clearla cq uer – it c ould disso lve the original pa inta nd ca use »ora ng e s kin«!

A Few TipsColour paints ca n be g iven a pa tina fi nish,too ! A touc h of »a ntique «tha t w ill tone

 dow n shrill shad es c an b e ac hieved withsolvent-based clear lac quer mixed with atouch o f oil pa int from the tube (oc hre + atouch of green and black), which is applied

to the surface. Dark wax, too, can be ap-plied a nd then w iped o ff so that only sma llqua ntities will rema in in any c revices of thesurface structure. Shoe polish, too, is worthan experiment. But always test for compati-

bility with the paint first!

Small figures are difficult to hold duringpainting. They ca n be fastened to a bottlecork with double-sided ta pe to make themeasier to grip and position. Dry and storeaq uarelle pa intbrushes with their bristles

forming a point.

Never apply gold bronze directly to theca s tings. Its suspension fluid will be ab -sorbed and the metallic particles will remainloos e on the surfac e. Alwa ys a pply a b as e

coa t, such a s c lear lac quer, colour paints or»Red S izing «sp ec ial primer, first .

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