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"Finishing Technology Hotline BBS" Postings by Topic

Ed. note: before the internet existed, there was a time when "Sysops" (system operators) ran publics forums via dial-up modems and "BBS" (Bulletin Board System) software. Here is one such discussion from 1992.

Plating on Plastics (POP)

Msg. #2486 in ** Ask Plater B**
Posted on 03/31/92 at 16:55:26
To: ALL From: GORDON BATHURST - Silver Plating Plastic We are a manufacturer of a line of closed loop silver recovery products ). We are interested in obtaining information on preventing silver (in a thiosulfate solution) from plating on the polypropylene recovery cells and instead plating on a Stainless (316) Cathode.Please leave message on board if you can help. Thank you.

Msg. #2489 in ** Ask Plater B**
Posted on 04/01/92 at 00:13:08
To: GORDON BATHURST From: TED MOONEY - Reply To 'Silver Plating Plastic'
Gordon, I don't think you're going to find it practical to keep a silvering solution that wants to reduce from reducing. I'd guess that the situation is that you have a solution containing the thiosulfate in a precarious balance--as soon as you touch it with electricity it spontaneously reduces. I realize that you are in the electrolytic cell business, but I think the conventional way of recovering the silver is to pop in a little bit of hydrochloric acid and recover the silver as precipitated silver chloride.

Msg. #2546 in ** Ask Plater B**
Posted on 04/26/92 at 23:09:19
To: GORDON BATHURST From: JOHN LOVIE - Reply To 'Silver Plating Plastic'
Gordon, one way to limit the rate at which silver is reduced by thiosulfate so that it can be plated out is to complex it. Cyanide works very well. Try adding potassium cyanide until the solution is stable. It's possible to calculate the amount of cyanide required. If you let me know the solution volume and silver concentration, I'll figure it out for you. Before I forget, the pH must be adjusted up to at least 11 before adding cyanide
- otherwise HCN gas can be evolved. Sorry it took me so long to reply. John


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