Posted by Srimay Basu (195.229.185.188) on January 06, 2008 at 04:27:01:
In Reply to: Black Anodized part sdiscolored posted by Agatha Bezovics on November 13, 2007 at 17:26:02:
: We have alum 6061-T6 parts, black anodized per MIL-A-8625, Type II. They look fine when we receive them but later discolor. At first I thought it was because of temperature/humidity testing, but we have now received some back from the field with the same problem. The attachaed purchsed Handles are also black anodized, but they remain pristine. What Can I do differently to retain the cosmetic quality of my parts?
Hi,
Is the black anodising obtained by using BLACK DYE after anodising? If so, then please check the product data from the supplier about the color fastness. There are very few Black Dye chemicals available in the market for outdoor application.
The best is to do by electro-coloring process in a Tin Sulphate bath after anodising. The result is extremely well if all parameters are followed rightly. It has been proven by Florida outdoor exposure test.
BASU,
DUBAL.