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Masking Thread Holes on Aluminum Extrusion to be Black Anodized

June 18, 2010

Q. Please help and answer.

I have an Aluminum plate with a durable #2-56 thread hole array on it, and it is going to be Black Anodized.

What technique or procedure should be performed either do masking with machine screws inserted or anything else in order to keep those thread holes clean

Thank You in Advance

Lang Pai
product engineer - San Jose, California

June 22, 2010

A. Tapered plugs are your best option for masking multiple small diameter threaded holes for anodizing. Plugs are available in a wide range of sizes to fit many diameters. Rubber, neoprene and Teflon materials are available.

dayton dailey Dayton Dailey
- Lake Zurich, Illinois USA

June 22, 2010

A. These are tiny holes and while tapered plugs work ok for larger holes, silicon pull plugs are the best as far as sealing, ease of use and time savings. Any of the plug vendors at this site will be happy to send you a small sample of 1 or 2 sizes that would work best. Try before you buy.

These plugs are reusable for a few times if you are not rough on them.

James Watts
- Navarre, Florida

November 2, 2010

A. Hello,

Is keeping the threads free a requirement, or simply a result of fears that the anodize will hurt the threads?

If you go with a type 2 anodize rather than a type 3 (hard) the threads will survive just fine. We've anodized more threads than ANYONE could count, and never had a problem from any quality angle. With thicker hard anodized coatings (type 3) you can make the edge of the threads so brittle that you end up compromising their ability to function, but that just isn't a concern with a type 2.

Good Luck.

Jim Gorsich
Accurate Anodizing Inc.
supporting advertiser
Compton, California, USA
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