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Sulfuric Concentration

Would the anodizers out there please let me know if hardcoat anodizing in sulfuric acid at a concentration of 270-300 gr/l is a common practice, rarely used or never used.

Thank you in advance for your help.

Rick Richardson, MSF
Dayton, Ohio
2001

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That number sounds pretty high - although it would still work. Common sulfuric concentration for hardcoat anodize is 165 - 240 gr/l.

David A. Kraft
- Long Island City, New York
2001

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We were using a 25%/vol bath for a while in our hardcoat line. The problem was it dissolved the surface faster than it built up. Thus coating for size was impossible. We have much better luck keeping all of our baths under 20%/wt.

Peter Faxon
- Oxnard, California
2001

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We use 247 - 303 g/l with pulse rectification up to 80V and have no problems.

Martin Trigg-Hogarth
surface treatment shop - Stroud, Glos, England
2001