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Rust is appearing on the I.D. of parts after zinc rack plating

April 24, 2008

We are a screw machine job shop running a 12L14 part 7/16' Outside dia, X 1-1/2' Lg.with a .136 dia. through the part inside dia.
The parts are clean and rust free before plating, however, after wire rack zinc plating rust forms on the inside diameters and the parts will be rejected by our customer.
This is a new plater for us, conveniently located and priced right, so we'd like to solve this problem.

Dan Schultz
Screw machine job shop - Delphi, Indiana, U.S.A.

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Hi, Dan. You will not get any plating in this hole (except near the ends). If the plating process is acid zinc, the parts will have been submerged in acid, accentuating the rusting. If the plater uses alkaline zinc the situation will be somewhat improved, although perhaps not solved. An oil or water soluble wax dip may help.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
April 24, 2008

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Dear Dan,

You can find some solution in the market for rust prevention in the ID of tubes. Pratical Examaple is fuel injection pipes.

As a supplier we have a chemical for it. That protects your component for a period of 4 weeks. It can be removed at the time of usage but hot caustic solution

You can enquire about that in your local area.

All the best,

S.V. Aurobind
plating process supplier - Bangalore, India
May 9, 2008