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Interference fit parts before anodizing

Has anyone had experience with anodizing 6061 parts that are assembled with an interference fit prior to anodizing? Will the resulting joint be reliably liquid tight?

Rod Takata
mechanical designer - Plymouth, Minnesota USA
October 14, 2009

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Hi, Rod. Parts "grow" substantially during the anodizing process. I am having a hard time picturing how you could put them together after anodizing if it was already an interference fit before anodizing.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
October 15, 2009

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First of two simultaneous responses --

I think that he is asking if he assembles the part and then anodizes it, will he have leakage at the joint.

If you are talking about the most liberal definition of interference fit, then I will say that there is a good possibility of leakage.
If he is talking about heating the female part and liquid nitrogen freezing the male part, then the leakage is significantly reduced. It then gets into the tolerances of both parts as far as things like roundness and run out.

Going into hot water and then cold water before the etch tank will reduce the visible effects as it will fill some of the "crack" with clean water rather than chemicals that will leach out later.

James Watts
- Navarre, Florida
October 16, 2009

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Second of two simultaneous responses --

The joint must be tight. Otherwise the current will not enter but the acid will and the aluminum will corrode.

Guillermo Marrufo
Monterrey, NL, Mexico
October 17, 2009