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Etching Zinc with Acid

I am considering using Muriatic Acid or Hydrochloric Acid to reduce the overall size of some zinc plated, zinc parts. Initial tests show I can get the .010" reduction I need by subjecting the parts to the solution for 10-12 seconds. Testing shows no weakening of the part. Any thoughts on if the black finish left over will provide any corrosion protection?

Thanks,

Mr. Pompeii
San Rafael Design Inc. - Colorado Springs, Colorado, USA
2003

Any zinc which is left will obviously offer some protection but depending on the thickness which is left it could be very limited. As the passivate will have been removed by the acid the zinc will start to oxidise fairly soon as well. It's not a step any plater would recommend.

Dougie Lightfoot
- Fife, Scotland
2003