Letter 554

Can we use aluminum cathodes in HARD anodizing

----

We are installing an additional Hard Anodize line in one of our Plants & want to know if it is OK to use aluminum cathodes in hard anodize. We know you can use them in normal Type II sulfuric. All our other hardcoat tanks are stainless & thus the tank is the cathode.
Any info would be greatly appreciated.

David A. Kraft Anacote Corporation Long Island City, NY

I had a small poly-pro tank that I lined with aluminum strips and used them as the cathode system. I also used a pulse rectifier and I loved the results. A very even coating.

Kelly Day
Micron Tech Inc.

David, the use of aluminum cathodes in anodizing (Type II or Type III) has been proven and documented for years. Refer to my technical article written MANY years ago for specific details. Generally, use 6063 -T6 or T5 ...Never T-52!!! All welds should be made with 5356 alloy welding rod. Anode:cathode ratio should be approx. 3:1.

Charlie Grubbs
- Alpharetta, Georgia