Remove thick copper plating from plastic

Q. For over 27 years our company has provided a bronzed keepsake for parents nationwide. We call it bronzed but it is actually copper plated and antiqued. The plated parts are actual castings of baby/children's hands or feet. In the past a bad plating job meant we grind the backside of the product and peel the copper off the plastic base. As business grows so do rejects and the time required to peel the bad parts can become excessive. It is not as simple as throwing it away and starting over. Each part is unique because it was made from a babies hand or foot impression.

Is their a chemical that I can drop the parts into that will eat away the copper without damaging the plastic base. The plastic used, monomer and polomer, is the same used in the dental industry.

Any help would be appreciated.

A. I'd first try ferric chloride ⇦ on eBay or Amazon [affil link] . Then I'd try sodium persulphate or ammonium persulphate.

Kevin Dowhower
- Lompoc, California, USA
2007

A. I would use 50% nitric acid, watch out for toxic fumes. don't let it get hot or you will ruin your master

Russell Richter
- Danbury, Connecticut, USA
2007

A. Of the two suggestions so far I would prefer the ferric chloride approach. Use 50-70% by volume of 42 °Bé FeCl3 solution
Much less risk of damaging the plastic.

Geoffrey Whitelaw
- Port Melbourne, Australia
2007