Why is my copper silver?
by Frankie Heimburger
(Pagosa Springs, CO)
Well, Stacy, I am not a chemist or a metalsmith (as you already know), so here goes....tried fusing some fine silver wire to a copper piece which I thought would be so cool! I used flux on the copper, torched, added the wire, torched & thought I had a great piece. Then, put the "finished" piece in a pickle (sodium bisulfate--ph decreaser--) for about 10 minutes to remove the firescale. Removed the piece, began to polish with steel wool & guess what---it's all silver!!! Not at all what I wanted---thought it might be just a quirk, so, I repeated it---all silver again....I had intended to try this method with a fold formed bracelet until this swapping of ions or whatever occurred. Any suggestions or am I in over my head in the chemistry department? Thanks for any insight you might provide. Miss your classes--absolutely nothing out here that even compares to the quality you provide!!!
Frankie, you always make me laugh!! You know folks are going to be trying to duplicate whatever you're doing so they can cash-in their fortune! Alchemists have been trying to do that for eons!!! heheheh Seriously though, the only thing I can think of to affect copper and turn it silver colored is exposure to zinc. It seems that either your pickle or perhaps even the solder you're using is the culprit. Perhaps even a crack in the crock-pot allowing some metal alloy to contaminate it? Perhaps some other metalsmiths have some answers here?
I tried to duplicate your results using fine silver and copper, and....my copper stayed copper colored. Because steel wool can be nasty — little pokey things in fingers and turning one's pickle into a plating solution — I mostly use 3m pads. They are available in a very fine texture like 0000 steel wool from Sculpture Depot
. Other sources may carry them, but I've never looked. :) I use Sparex no.2 as a pickle (sodium bisulfate) which works really well. I would check your pickle pot too and make sure there are no cracks in it, and replace your pickle.
Before you go through the trouble of replacing your pickle, check to make sure that you are using a solid copper item. Another possibility to this conundrum is that you are using something that is copper plated over a silvery base metal. When you use the steel wool, you are removing the thin copper coating revealing the base metal underneath. You can also burn a plating off.
What kind of solder are you using? Silver solder or one of those paste thingies for welding pipe? If you're not using a good quality solder, get yourself some silver solder in easy, medium and hard. Also a good silver paste solder is handy to have. I prefer the wire form of solder as I can leave it round or flatten it as I see fit. I just got some new copper wire solder that is copper colored instead of grey and I like it a lot for copper joints. I'll email you the information. It's sold by the ounce like silver solder.