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  for Metal Finishing since 1989
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Rack marks in bright acid tin plating of gaskets

I am plating large metal rings gaskets. On a rack made of copper with stainless steel all-thread as my hooks the rack has been coated with plastic except for the hooks. My question is it leaves a mark on the ring where it sat on the hook. Is there any way to help to stop that without needing to move them by hand? Any suggestion will be helpful.

Jerry Hernandez
Ring gasket - Houston, Texas
2005

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If the parts must be rack plated rather than barrel plated, rack marks cannot be eliminated . . . but they can be minimized. When you say "all-thread" I infer something of larger diameter than necessary, and with thread crowns that will draw current. Can't these hooks be made of smooth stainless steel rod rather than all-thread, and of minimal diameter? Have your rack manufacturer redo a couple of the hooks this way and see if that minimizes the rack marks to the acceptable range.

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
2005

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I have been out of active plating for a few years, but I doubt if any rack manufacturing company would make a rack with allthread hooks.
Why not buy a professionally made rack from one of the larger rack manufacturing companies made for your specific part and if it works well, modify your existing racks.

James Watts
- Navarre, Florida
2005