Electrostripping of metals

A. Hi Giulio. Unfortunately there is no "such as" involved. Every metal you wish to strip, and each substrate you wish to strip it from, form a pair that requires a different chemistry. In some cases electricity is required; in other cases it isn't. And in some cases there is no chemical that will strip a certain plating from a certain substrate.

And compounding the problem further, it can depend on why you're stripping it; if replating, you need a pit-free, pore-free surface, for example. Please give a specific example. Thanks!

A. Plating layers are very thin -- you would have to strip a large number of objects to achieve a 1 ounce refined bar of any metal... In my home-shop I am not allowed by local laws/covenants to have stripping … but I am allowed to have a sand-blasting cabinet. I have a setup for stripping silver and golds that involves no chemicals or platers. The cabinet has a vacuum duct where the sand used to fall- replace the 90 degree duct trap at the bottom with a small bucket (I have a 5 gallon with the lid fitted to the cabinet base). You will need one for golds- and one for silver (or each metal you want to refine- keep them as separate as possible.) The cabinet has a flex-shaft run into it with an abrasive wheel- Put items in the cabinets, hands in the gloves- and grind the surface lightly all over- mechanical stripping of the layer of plating- allow the dust to settle- then like a bench-jeweler- sweep the "lemel" or filings into the duct. The fellow I adopted this from has a spritzer bottle in his cabinet to wash the corners and gloves with- the dampness keeps the dust down as well- let the bucket settle- and let the water evaporate. Send the filings (called Lemel) to a refiner.

A. Hi, Tony.

Thanks, but actually I have no experience in it at all; I've just worked in the plating industry a long time, and stripping and replating of in-house rejects is a somewhat common process. But as I mentioned in my first response, years ago, it begins with knowing what metal you wish to strip, and what the substrate is. What is underneath the gold? What is underneath the silver? If there are multiple plating layers below it, is it important to preserve them, or is there a layer of nickel that you are willing to sacrifice? Sometimes, dissolving the nickel layer between them is the way to separate them. Very importantly, why do you want to strip it? Are you going to replate it; if so, will you be replating with the same metal? Are you going to paint it. Or are you referring to recovery of metals from e-waste (which I don't even like to talk about because many environmental organization are vehemently against it; it hits the e-waste with a wrecking ball, scattering toxics everywhere, while "cherry picking" in a fashion that guarantees that the remainder of the mess will not be recycled).

There are often no answers to abstract questions, only specific answers to very specific situations. What do you want to strip silver and gold from and why? Don't even think of trying to recover precious metals until you know their thickness because you have no way of monitoring whether your operational efficiency at any of the many steps is 99% or 1% until you have calculated how much you started with and tracked it through the process. Thanks. Best of luck.

Regards,

A. Electroparting or stripping is the separation of two or more metals, done electrolytically. For instance, if Cu is to be stripped off from steel.

"Recovery and Refining Of precious Metals"
by C.W. Ammen

on AbeBooks

or eBay or

Amazon

(affil links)

A. Hi cousin Anand. Please read carefully at least this one page and answer all of the questions about your situation that we've already posed; please tell us who you are, exactly what this item is, and why you want to strip it. We don't know at this point if you're a metal artisan trying to refinish a precious antique tabernacle, or a scrap dealer with a bucket of shiny stuff :-)

When you need help with a very specific situation which you are able to very carefully detail, our readers can often help. When you are looking for general education about a field of learning, books are usually a much more efficient way to go than asking the readers to pull teeth. Thanks!

Regards,