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  for Metal Finishing since 1989
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Maintaining consistency of color with bronze anodizing

 

We are having problems maintaining consistency in color from beam to beam and on single pieces of aluminium anodized in 543 bronze. Are there any new chemicals/processes that will enable us to maintain consistency on this color.

Ian Lowe
Anso Finishing - Cape Town, Western Cape, South Africa

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Which process/chemicals are you using now?

  
Tom Pullizzi
Falls Township, Pennsylvania
 

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Bronzes are a nasty color to maintain uniformity, but it can be done by tightening up every step of your process, not just the dye step. Start out by cutting all of the process paramater variables (the plus or minus part) in half. Next do all of your analysis twice as often as you do now and it will be better. If that is not good enough, cut it in half again and do another twice as much analysis. When you find out that it works, you can loosen up some of the requirements until you find what is the critical one in your shop. You might find it as out of sight as the quality of rinse waters. Extremely few shops daily check for the amount of dyestuff in the tank on a daily basis. pH varies with drag in. Temperature is not constant, aluminum content kills it. Lots and lots of places to look. This is why real quality costs money.

James Watts
- Navarre, Florida