Anodizing_Tutorial (Slightly Outdated, Good Setup Info)

8/6/2019 Anodizing_Tutorial (Slightly Outdated, Good Setup Info)

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Anodizing a cast Tannery Shop receiver

CMA Statement: The process described in this article deals with electricity, sulfuric acid, hot & toxic

liquids, and boiling water. However, I have worked in several labs where safety was a much greaterconcern, I mean we are just working with "discharged" battery acid. I was also the Safety, Health andEnvironmental auditor for a large company. And believe me, I am a big baby and I don't like pain in theslightest. So, I assured my own safety. If YOU intend to use this guide, YOU will be the one in chargeof YOUR safety, as I won't be there to assure you are careful!

Note: A special thanks to Fibergeek at Roderuscustom Forums forums for his technical expertise, without his kind and helpful words of encouragement this article would not be possible. A thanks as well toBuilder Squad's excellent website, without which I would have been totally lost on putting a drill or fileto an 80%'er. And all of the various members ofAR-15.com, and Roderuscustom Forums. Many of you

asked or answered most of the questions that I had before I knew that had them.

Here is what it would look like with out any treatment or coloring.

I originally decided to try my hand at the anodizing/dyeing of an AR -15 Tannery cast lower after reading that no one washaving luck doing it. That was really all I needed (I'm stubborn that way!). After a lot of exhaustive research I came across aseries of posts on the successful anodizing/dyeing techniques by Fibergeek. His posts seemed to a: make sense, b: have theexperience to back it up (he's an electrical engineer), c: he has successfully anodized/dyed cast aluminum parts before (See

Tanneryshop's Website). This was all I needed, well almost.

First off, I ordered a Tannery Shop 80% cast aluminum lower receiver for an AR-15 type rifle. If you aren't familiar withthese I encourage you to check them out at Tannery Shop. Other sources for AR-15 type receivers are available from Sgt.

Freedom, Shade Tree Armory, but I'm not sure that either of these would have been suitable for my particular skillset/tooling. As the other suppliers have less or different machining that needs to be done. Other sources for information are

AR-15.com, The Builder Squad, Mujahadeen AR -15, and of course Roderus Custom Forums.

I should start off by saying that this is the first "real" metalworking project I've taken on. I have never machined anything


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before this. I have never anodized anything before either.

When I got to the fork in the road of finishing, I had basically 2 options: anodize and then paint or anodize and dye. Eitherdirection you take still requires the anodizing step. However, I based my decision on the dyeing process being only 1 extra

step added to the anodization process. Whereas the paint and bake method still requires the anodization and sealing, but thenyou have to paint, (which I must mention is a skill I don't seem to possess), and bake the finish on in an oven (obviously). Idon't have an extra oven and I know my wife would not allow "her" oven to be used for this purpose. So, I decided on the

dying process. As Fibergeek so eloquently put it, "Cleaners never use PAINTED guns, it wouldnt be professional."

I procured a "lab-type" power supply from a seller on E -bay, per the suggestion by Fibergeek. I have 2 battery chargers in mygarage, but decided to get the power supply after reading about the different obstacles/deficiencies related to battery chargers.I believe there is a way to make them work, but it seemed to be less work to get the right tool to start off with. If this "hobby"

is as addictive as people say, and my actions indicate my hopeless addiction, I'll get my monies worth out of it.

I ordered Black HBL dye from Caswells , it's more expensive than the other colors, I'm not sure why. From my reading ongeneral anodizing I found that a true black is a hard color to anodize. Perhaps that sheds some light on the increased price. I

believe others have used RIT clothing dye, but apparently their black will not provide the same true black as the Caswellproduct. The RIT dye is not UV safe and will fade with time, left in the sun. I don't leave any of my guns in the sun so I don't

know how much of a problem this would really be. Furthermore, I have yet to hear of a successful use of the clothing dye(however, my wife reports limited success with this dye on actual clothing). I wanted to do it right, and the only person I've

found to have success is Fibergeek and this was the product he suggested.

Next, I got some aluminum wire (Radio Shack) and some acid (auto parts store). I located my acid container (on sale at Wal-Mart for less than a buck) along with a glass candy thermometer for around $2, my dye tank (broken pressure cooker fromGoodwill $2), and my sealing tank ($4 -damaged-enameled Dutch oven pan at the local Dollar store). I set up a table at one

end of the garage and laid out my "tools".

Here's my list:

1. Power supply-Pyramid 0-5 amp 0-30 volt

2. Acid container 5.7 Qt-Rubbermaid

3. Aluminum Wire 40 ft.


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4. Anodizing/dye/rinse tanks-2 SS pots

5. Camp stove (dyeing/sealing step)

6. Black HBL aluminum anodizing dye

7. Aluminum foil (Cathode)

8. My wife s watch

9. 6 gallons of distilled water

10. 1 can of brake cleaning spray

11. 2 quarts of battery acid

12. All the suspected safety equipment-gloves-glasses-apron

13. A glass candy thermometer-Wal-Mart

14. A box of baking soda to neutralize any spilled acid.

You'll want to wear clothes you don't care about; I doubt any harm will come to them but better safe than sorry. I wore oldwork clothes and an old pair of steel toed work boots, my apron, safety glasses and rubber gloves for the duration of my

work.

I set up the camp stove on the other end of my garage. I had gotten it down from the rafter in the garage a couple of daysprior, and got it fired up after cleaning the thick dust off of it. Seems that I don't go camping as much as I used to.

This is the the anodizing tank set up and running. You'll note the similarity to the other anodizing guides available online.

I bent my cathode out of the aluminum wire into a flat rectangle slightly smaller than the plastic "shoebox", looping one endaround the other (picture a cowboy's lasso, but square) with the other end bent at a 90 degree angle up and out of the shoebox.I then folded over the end and added a "hook" for the underside of the shoebox, to hold the cathode down against the bottomof the box. I added some strips of aluminum foil scrunched up somewhat loosely around the perimeter of the square in the

bottom of the box to increase the surface area of the cathode.


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I then attempted to make my anode end, let me just say that bar the nervousness of passing electricity through sulfuric acid,this was one of the more difficult steps. I'm guessing that I was just making it harder than it should be. I ended up folding aninch of wire over, pounding it slightly to a point and then twisting it tightly up into the grip hole. My first couple of attempts

came loose, but the third time was the charm and I was able to solidly connect the wire to the receiver. Then, just as thebuilder squads process I bent and twisted the wire around a thin stick of plywood scrap so that the wire would hold the

receiver on it's side horizontally as near the bottom of the box as possible, with out touching the cathode.

This is the anode (receiver) just to get an idea of how it should look.

I set up my power supply above the "tank" so the gauges would be easily seen. I connected my leads and began mixing myacid solution. Remember the triple A rule for making acid solutions-Always Add Acid. I decide to use a 2:1 mixture, 2 partswater to 1 part acid. I used 1.5 quarts of acid and 3 quarts of distilled water for my solution this submerged the receiver but

didn't fill the tank to the brim. After cleaning the receiver with soap and water I used the better part of a can of brake cleanerto degrease the receiver. And after letting the receiver dry I set the anode (receiver hanging off of the stick) into the acid

solution.

This is a dark picture of the set up (the red light is the power switch on my power supply). You can see my dye tank andcandy thermometer in the foreground.

I opened the garage doors and let plenty of fresh air in, even with both of them opened the fumes were fairly strong at timesdepending on my location and the direction of the wind. I connected the power supply leads and tried to set my pws for


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constant current mode. I was unsuccessful in doing this however (I don't think I let it dead short long enough). So I used thedials for raising the amperage and voltage by hand. It was only difficult at first and after about 5-10 minutes I wasn't

adjusting as much as before. It was at this point I realized that I didn't have any sort of watch so I ran into the house to getone (my only safety violation I might add, as I was forced to leave my reaction unattended). When I came back the power

supply was beeping indicating that the there was a short, and by the time I got into the garage the power supply had set itselfto constant current mode. Instead of running at the 3.0 -3.2 amps I had been adjusting for the pws set itself to run at 3.8 -4.2

amps. The voltage however was increasing and after shutting off the pws in a vain attempt to reset it. I decided just to watchmore closely and let it anodize at the higher amperage.

Here is the anodization tank happily bubbling and fizzing.

The pictures that I took and the pictures on the other websites really don't do justice to the bubbling and fizzing that goes onduring this reaction and with the elevated amperage I had some really good fizzing. It's not like water boiling over in a

kitchen pan, but more like a really fresh glass of 7up fizzes. Now think of almost a gallon of 7up in a shallow pan and howthat would fizz and you'll understand. Every now and again a larger bubble would make its way up from the cathode as welland when these bigger ones popped at the surface I noticed that they splashed out of the confines of my tank. A deeper tank

than I had should take care of this problem and thank the lord; I was in the garage and not the kitchen.

The voltage rose slowly and peaked out at about 20 when it had fallen back to about 19 I decided the anodize was donegrowing. I shut the pws off and removed the receiver, and rinsed the receiver off with some distilled water. During the lastfifteen minutes of the anodizing process I had mixed the dye, per the instructions, with 2 gallons of distilled water. I poured

the mix into my dye tank. In retrospect my dye tank (a old pressure cooker with missing parts) was a little smaller than itshould have been but in the end I was able to keep the receiver submerged in the tank. I slowly brought the temperature up to

140-150 and then let set at 140-150 for about 20 minutes. When I removed it from the dye it was a thick black color, but Irefused to get excited yet.

While the dye was coming up to temperature, I had started my sealer tank (filled with distilled water) boiling on the kitchenstove. I figured this was easier than using the small camp stove to boil a gallon of water, plus since there were no chemicalsin the house I would not be killed by the wife. Once the water was boiling pretty well I shut off the stove burner and took it

out to the stove. After I lit the burner it was back to boiling in a matter of minutes.

It was the moment of truth, time to see if this project was going to have a happy ending. I put the receiver, still wired on tothe stick, into the sealing bath. The water immediately turned as black as the dye bath. I couldn't see the receiver anymore. I

held back my curiosity as long as I could stand (maybe all of 1 -2 minutes) and I plucked the receiver out of the sealer bath. Ithad gotten hot enough that the water was evaporating off of the receiver as I held it up to the light -it was black. I carefully

returned the receiver to the sealing bath and commenced with a little know amateur gunsmith practice called the happy dance.Thank goodness I had the garage door shut!


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I rinsed the receiver in some extra distilled water, still unable to believe that I had made this work. I carefully removed the

anode wire from the grip screw hole and began applying CLP with an old sock. I figured the black would wipe right off, anda little did, but it was still black. The finish does have a slightly reddish tint to it in the right light, but I am amazed at howwell it matches the other parts. The CLP really brought out the black and made it look good. If you look real close you cansee it's mismatched slightly and as has been said frequently anodizing hides no sins. I intentionally left some tooling markson the receiver, my casting had some irregularities, and these are all visible upon close inspection, but overall I am pleased

and proud of myself for having accomplished this project.

Here is the finished product.

The last step was cleaning up the mess. I don't know that it was necessary but I rinsed everything used for the acid solution inwater. Then I soaked everything in the sink in a baking soda brine before washing it all. I sprayed the bench I was working on

with some baking soda brine as well with an old squirt bottle just to make sure there wasn't any acid lingering around. I savedthe dye and the acid solution for the inevitable next project. I have about 30 ft of the aluminum wire left over -give or take and

1/2 quart of the original battery acid. So really the only consumables are electricity and heat.


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Here is another picture of the finished receiver before the CLP rub down.

Documents

Anodizing_Tutorial (Slightly Outdated, Good Setup Info)