TCP with color?

[jgrav2]

We are specifying the new TCP conversion coating for some alumium parts and we have always specified "gold" color to our CR(6) coatings. I understand adding dyes to TCP makes it fail salt spray tests. We don't need a lot of protection since the end product is used in laboratory conditions. Will platers be adding color to TCP coatings if it is specified?

 

[kenvlach]

Not likely. Not considered a good idea:

http://www.finishing.com/398/39.shtml

If you are willing to spend enough money, better to bright-dip, anodize & dye gold.

Very few dyes are available for chromate conversion coatings. Those used for chromated zinc (blue, green, red) should work for chromated aluminum, but it's doubtful that such a gold dye exists since there wasn't a need.
Also, if you do specify gold dyed, your metal finisher may try an anodizing dye which may bleed & fade since cannot seal properly. A tinted lacquer should work, but you'd have to mask off or post-clean any electrical contact areas.