How long does color dye last

[docrak]

I mixed up a batch of Caswell black dye about a couple of weeks ago. I have only put a few parts through it and keep it in a closed cooler when I'm not using it. My parts are coming out anything but black right now. How long can I expect dye to last or is this another problem like cross contamination or pH inballance?

[Tim Wiltse]

docrak,

I can say that I am using Caswell anodizing dye that I mixed up Oct' 02' with 100's of parts run through them and they are working as good today as they did when new.

Tim

[docrak]

My parts have a thin oxide coating (0.003 - 0.004 Inch). Some parts come out brown and some come out with a slight purple hue. The parts have a surface area of 68 INCH^2. I soak them for 15 minutes at 140 F. Soaking longer doesn't help.

The parts came out perfect at first, but slowly began to degrade.

[mcaswell]

Please post a problem report in our support section.

Problems with coloring are usually caused in the anodizing step. Small variations in power and temperature of the anodizing bath can change the pore size and therefore retain more or less dye, changing the color.