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Aluminum Hard Coating Thickness

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I am reviewing and editting my company's process standard manual on the Aluminum Hard Anodizing Process. The current manual doesn't give us time needed to build desired coating thickness, which is typically about 0.002 +/- 0.0002 inches.

We presently use a current density of 40 amps per square foot for our process. Comparing to other documents on the same subject, I found that the time needed is varied upon the current density used and the type of alloy. Is there any way to determine the time elapsed?

VY TRAN
airline - Atlanta, GA, USA

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Hi Vi, One method of determing time to build your required thickness is using the "720 Rule".

This rule states that Anodizing Time = (720*Film Thickness)/Current Density. I've found this to be pretty accurate. For example 720*2=1440. 1440/40=36..so yer time to build 2 mils (at 40amps/sq.ft.) would be 36 minutes.

Marc Green anodizer - Boise, Idaho

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Please say me process for making hard anodized aluminum cookware.

Thank you,

Mohammad Ahmadi
- Arak, Iran

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Tell me the process for making an airplane and I'll tell you the process for making hard anodized aluminum cookware :-)

Seriously, Mr. Ahmadi, the process specs would surely fill several volumes and doubtless involve a great deal of proprietary information as well. If you will tell us your situation and ask a more limited question, someone may be able to help you.

Ted Mooney, P.E. finishing.com Brick, New Jersey