Home anodizing aluminum

[maccrazy2]

I have been watching YouTube videos on anodizing lately. I gave it a try once years ago (pre internet) using an article in hotrod magazine. It was less than successful to say the least.

I’m building relatively small items all the time and would like the ability to color them for a finished appearance with durability being a side benefit. Do any of you guys have experience doing this in house? I have everything I need minus $30 in acid and some distilled water. I was going to give it a try using a charger and if results merit I may get one of the DC power supplies for $70 for fine tuning.

[bruski]

I have done some anodizing on some small engine parts like this valve cover. It is not polished yet and the tool marks are visible on some areas. The aluminum needs to be clean and polished up before anodizing because every thing will show up under the colors. If you want a brushed look under the color, that would be much easier than the polished. Clean everything twice including finger prints with acetone then distilled water. After the distilled water, keep it wet at all times and put it into your acid bath. I used lead for the other electrode and use aluminum wire for your parts. Crank up the amperage until bubbles are forming and keep it there until the surface is milky in color. From there, dip it into your distilled water then while still wet put it into your HOT colored die until it is as dark as you want it to be. From there I used steam to lock the color into the pores. You can use simmering hot distilled water also but some color will bleed out.

 

  For best results use colored dies that are developed for anodizing. They work great and are concentrated to mix with distilled water. 

 

bruski 

[Sparky_NY]

I have a friend that did quite a bit of home anodizing.    I have been very tempted to try it myself.    Everything Bruski said is in line with what I have learned.   ESPECIALLY using commercial dyes made for the purpose instead of the common RIT dye method.    Apparently, there is a big difference in the results using dyes made for the job.

 

Do post your results and findings when you try it again !

[maccrazy2]

Thanks for the info. This is the first I have heard of using steam to seal it. Do you boil it after the steam or just the steam alone? What type of steamer are you using?

I used to have a small handheld spot cleaning gun I used for swelling out wood dents but it would not of been practical for this.

[bruski]

Your parts will be safe to boil after a good steam treatment. Actually, the water should be just under the boiling temperature around 200 degrees F. It is the 200 degree temperature that closes the pores in the new oxidized layer so your steam generator needs to be large enough to generate enough steam to heat the part up without pressure blasting it. That would wash out some of your die in the pores so anything gentle will work. If you have a pot large enough to put the parts on top of a screen with boiling water under them and a lid on top works great. A glass lid would be even better.

 

  The main thing to watch out for is do not let your parts dry out while sealing them or the surface will have blemishes on it even with distilled water. Let the parts cool under water in a separate pot after sealing them because they will be hot and dry to fast for you to wipe them off after sealing. 

 

 After they are cool and dry you can put a coat of wax on them and polish the surface to a nice shine. Do not use polishing compounds because they will cut into your anodized surface with the abrasives in them.

 

bruski

[maccrazy2]

Well I have acquired everything give it a try. I bought a power source so I can dial in the amps/voltage more accurately. I’m working on finishing up some cues for an upcoming show next month. After that is over I will try this out.

I still need to figure out some form of agitation, either a bubbler of some sort or one of the submersed units caswell’s sells.

[maccrazy2]

Well I made my first attempt today. It was looking promising but I am having an issue getting the power supply set on constant current mode. I went ahead and ran a couple scrap pieces but ultimately the amperage was about half of what it was supposed to be. They looked great after soaking in the dye but lost a lot of color during sealing.

I believe once I get the power supply sorted out it should work great

[maccrazy2]

The test pieces.

[bruski]

The aluminum should have a milky look to it after the pours open up while it is in the acid bath. Is that aluminum wire, if not it should be.

 

bruski

[maccrazy2]

Titanium wire. The surface was whiter than when I started and had tiny bubbles coming off the whole time the power was on. The amperage was around 1/2 of what it should of been so I’m not surprised it didn’t turn out. I will give it another go this week and see if I can get the output higher.

[maccrazy2]

Second attempt went much better. I got the amperage where it should be. I didn’t plan on making a full run at it but everything was looking good so I went ahead and left them in. I would of prepared the test pieces better if I had expected to run them. You can still see the writing from the mill on the sides. I left it on intentionally to see if the lye would remove it.

I’m confident enough now to go ahead and set up a nicer setup for doing this. I plan on setting up a mechanics cart with a little bigger tanks with circulators and heaters in each as needed. I did these with Rit dye. I already ordered some real anodizing dye.

The second photo is them laying on a piece I had professionally done. The color and sheen is quite close. I did notice these did not take on dye as dark as the first test however those parts were machined and these were just old bar stock I had laying around so I suspect the oxide layer on the surface was the reason for the variance. However, the first parts looked darker it all bleed out during sealing. The second ones stayed the same color as they were before sealing.

[bruski]

That looks very nice. The oxide layer is removed in the lye bath to expose fresh raw aluminum.

 

bruski