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  for Metal Finishing since 1989
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Anodizing Questions

2001

What is the cost comparison between an aluminum chromate conversion finish and conventional sulfuric acid anodizing?

Is there an advantage with an anodized coating relative to anodic corrosion resistance?

If using an anodized coating, should the sealing step be eliminated in trying to achieve better adhesion between the aluminum and molded rubber? Or would the lack of a seal offset such an advantage by leaving those surfaces that are not adhering to the rubber with a surface more susceptible to corrosion?

Joseph N. Gormley
Gormley Sales - Grosse Pointe, MI, USA

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First of two simultaneous responses--

In my opinion sealing is not important when the anodized surface is to be rubber coated. I think it is important, however, that coating should be done within 48 (Or 24hrs?) hrs after anodizing. Sealing is important for dyed anodizing to prevent fading. Unsealed anodized aluminum will, in time, develop sealing on its own.

Dado Macapagal
- Toronto, Ontario
2001

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Second of two simultaneous responses--

If the process you are going to use is rubber bonding with some sort of adhesive layer over top the aluminum (I have a customer that does this) my suggestion to you would be chromate conversion coating, its less expensive, and its incredibly well suited for this process.

Matthew Stiltner
J & J Plating Company - Toledo, Ohio
2001