Anodizing not holding color

[slug New User Find all posts View Profile Close slug]

I've been having a problem with my anodizing lately. After I seal the
parts in a bath of boiling distilled water, the color seems to just
rub off, sometimes almost completely.

I'll outline my process quickly. I first prep the parts by washing
them thoroughly with dish soap and then submerging in weak nitric acid
for about 5 minutes. After rinsing, they go into the tank of Sulfuric
acid, with approximately 1125 Hygrometer reading. I use a battery
charger from Wal-mart as a PS. It's rated at 10 amps, and it rarely
pulls more than 50% of the current as reported by the gage.

I anodize for 90 minutes, then remove the parts, rinse, and submerge
in RIT clothing dye mixed with water at approximately 130 degrees F
for 10-30 minutes, depending on color.

Finally, I seal in a bath of boiling distilled water for 30 minutes
(have tried steaming as well, but it didn't work too well).

Does anyone know why my parts do not seem "color tight?" Am I not
sealing them long enough? Also, sometimes my parts have lots of light
"spots" on them, where it appears that no dye was absorbed at all.
does anyone know what this is from?

[mcaswell ******* Inc Founder Find all posts View Profile Close mcaswell]

If you have one of our anodizing kits, please post a problem in our PRS support tool and we'll be happy to help out with this issue.

Generally though, if your solution is too warm, or you use too much power, the anodize pores are too large and don't hold dye well.

Also, using RIT dye isn't the best idea. A professional anodizing dye gives much more consistent results and richer colors. See http://www.caswellplating.com/kits/anodizedye.htm

Using professional quality chemicals, like desmuts, sealers and dyes, really does make a difference in the quality of the product.