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Stripping various platings and disposal of the waste

I have various spring washers plated in zinc, black oxide, nickel and galvanized. I believe I cannot use an acid because of hydrogen embrittlement (or some other type of reaction). I would like to use a tumble deburr preocess, but am not sure of the proper disposal. Does anyone know how I should go about this?

Mike Smith
engineer - Ohio, USA
July 21, 2011

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Hi, Mike.

It's not clear to me whether you are from a plating shop or a fastener distributor or what. But I'll remind the readers that the plating industry is categorically regulated, meaning that disposal of all waste products is regulated. So it's not just a question of what is the best disposal method, but what disposal methods, if any, you are authorized to use. So it might be best to send the parts back to a plating shop for stripping unless you already have an in-house plating installation.

If these are simple Belleville washers rather than something more exotic, replacing them may be more cost-effective than trying to tumble the coatings off. I can't say that tumbling won't eventually work, but it might take many days. Best of luck.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 22, 2011

I am not a plating shop. These parts are springs made from high strength steel (6150 austempered). To remove the coating a plating company wants to use a sulfuric acid then recoat, but I am concerned about hydrogen embrittlement. What would you reccomend?

Mike Smith
- Ohio, USA
July 29, 2011

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Hi, Mike.

Hydrogen embrittlement is an issue but maybe not an insurmountable one. Parts can usually be stripped, baked for embrittlement relief, plated, and baked again for embrittlement relief. But the stripping procedure will vary depending on what finish is on the parts; sulfuric acid or hydrochloric acid will work for some finishes but not for all.

It is probably possible to sandblast most of these finishes off, but that can be quite labor intensive. I would investigate the cost of replacement parts as you may find them less expensive than stripping and replating. I hope someone else will comment on the feasibility of tumbling the finish off because I have little confidence in it being practical, but that is based on guess rather than experience.

Regards,

Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
July 29, 2011