Black Anodize Turning Brown

Has anyone heard of black anodize, class II type II turning brown? If the seal was not good enough, would it cause the browning?

First of two simultaneous responses-- 2001

Hello Daryl,

Poor seal and/or exposure to U.V. light can fade the color. Have a sample part seal tested. One such test is dye absorption. Check with your local anodiser to see if they offer this.

Good luck,

Second of two simultaneous responses--

You did not say the conditions for turning the black color into a brown color. I have seen the black parts that are well sealed turn to brown color under a temperature of 80 °C for 20- minutes. This has to do with the heat resistance of the black dye.

Hi Daryl,

I have a similar problem w/some parts from my customer turning brown. Did you happen to find the cause of this problem.