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Dying and Nickel Sealing Problems

I have two small anodizing questions:

1. I'm using dyes from Clariant, mixed in tapwater w/o buffering and pH-adjustment. My colors are slightly lighter than those displayed in Clariant's color card. I use the same concentration. Any clue why?

2. I'm using a nickel salt to pre-seal after dying to keep the dye in the pores. Which is the lowest safe operation temp of this operation.

I hope someone can help me out I wolud be a great help!

Martin Dehlin
- Sweden
2000

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Question #1

We haven't tried using the parameters you've stated but why don't you try the opposite- DI water, buffered, temp/pH adjusted. That works fine for us.

dado macapagal
anodizing - toronto, canada
2000

You have to adjust the pH and maintain the concentration of the dyes within their spec'ed range to get the appropriate color tones. Also, you can (as you stated) adjust the pH in the bath to get lighter tones, such as a pink tone from a red dye. Lower immersion times do this also, but, because of the lower times you have less dye immersed into the pores of the material, and when sealed some of the color will bleed away and the color will be lighter than you desired.

Matthew Stiltner
- Toledo, OH
2000