Silver re-melt -- Dave2C or others---

[P.W.Berkuta]

OK -- I have some silver scraps -- Sterling, coin, 99% --- and I want to melt it down and flatten it so that I can reuse it. Has any body done this? If so -- what was your process -- flux, flat open mold, did you use an cast iron ladle - or? I don't have much and it is not worth the cost scrapping it at a jeweler I'd rather try to remelt it myself. Any hints - suggestions .

[davec2]

P.W.

Your scrap can be re-used without further processing (i.e. refining) for what you have in mind.  The process may depend somewhat on how much silver you have.  For an ounce or two, the scrap can be melted with a torch in a ceramic melting dish or ceramic ladle. (You can also melt small quantities on a charcoal block). The torch used will need to be of sufficient size to generate the required heat (I use an acetylene Prest-o-Lyte torch) and the melt should be fluxed with common household borax.  The lump can be left to cool in the dish and pried out after it solidifies but before the flux gets hard (and you can re-heat, if you miss this window) unless you are just going to pour it out in the molten state.  Once cooled, the lump needs to pickled in warm hydrochloric acid (pool acid) diluted about 2 to 1 with water.  The lump can be hammered into sheet, with frequent annealing, but it is a slow process from a thick lump.  A more useable form, if you intend to make sheet, would be to do a cuttle bone casting of a plate shaped piece and then hammer it out as thin as you may need it.  (Cuttle bone is available at pet stores.)

This can be done with an oxy / acetylene torch, but the metal can be easily overheated and "burnt" with this type of welding torch.  A propane or Mapp gas torch will not generate sufficient heat unless you are melting a very small (i.e. a quarter ounce or less) amount of scrap silver.

Here are some useful links for things you will need to do this with as little investment in things you probably don't have:


Ceramic melting / pouring dish: 

http://www.riogrande.com/Product/Clay-or-Silica-Melting-Crucible-and-Handle,-11_dash_Ozt/704119?Pos=1

http://www.riogrande.com/Product/The-WHIP-Fused-Silica-Crucibles-and-Pinch-Tongs-Set/704222?Pos=1

Charcoal block:

http://www.riogrande.com/Product/Hard-Charcoal-Soldering-Block-with-Pouring-Channel,-2_dash_34/502022?Pos=3

Cuttle bone:

http://www.amazon.com/Living-World-Cuttlebone-Large-Twin/dp/B0002DH2YW/ref=sr_1_7?ie=UTF8&qid=1435537103&sr=8-7&keywords=cuttlebone+bulk

Cuttle bone casting information:  (There are several of these videos on YouTube and they show the rest of the process I am explaining in this post.)  Here are two: 







If you get stuck, PM me and I can help out.

[docone]

Good advice.
You can also use a piece of wood to melt on. Same effect as charcoal. I use a plumbers propane torch, about 14$ at Ace. Hold it upside down and melt on the wood. Use Borax laundry detergent, or ant poison. The ant poison is Boric acid.
Put the pickle, pool acid in an old crock pot and heat it on the medium setting. Do not use iron tools to remove.
To make sheet stock, melt in framing lumber, then pour into a mold carved into a piece of lumber. Rather than a lump, it will have started to make the sheet shape.
Just carve into the lumber, sand a little, and pour.
When I first started silver casting, I made a crucible in the lumber to pour with, and carved little shapes. Crosses, rectangles. I messed around with it.
When you hammer it, and if an edge starts to crack, merely file the crack out, anneal, pickle, and hammer.
You will learn a lot. Enjoy the process.

[P.W.Berkuta]

Thank you both for the info - it was VERY helpful and great links Dave. I ordered the melting crucible with handle (it comes with two sizes). I have a lot of old worn coins that you can't make out much info on.  I been saving my scrap silver inlay waste. I want to make sheet stock.
I have most of the items you both refer to except the acid. I'll use my oxy-acetyiene torch to melt. I like the wood mold idea as I have enough of that and a mill to hog out a form. As far as the acid is concerned can I use anything else or can I get small quanties of it - is it really necessary - don't want to have too much extra of it around & I don't know of anyone with a pool. Again thanks to all and if I need extra help I will be sure to let you both know .

[Shreckmeister]

Another option for the coins is to have them rolled flat.  My friend had a coin roller and it made nice flat silver sheets I could cut inlays out of.

[LRB]

  Pool acid is usually cheaper than two soda drinks. Last I bought was $1.00 a gallon. It may be $2.00 a gallon now.

[docone]

The powdered form is
Pool PH Reducer. Home depot has it as well as Wally world.
I mix mine untill it does not all dissolve in hot water. A little does not go into solution.

[davec2]

The Ph reducer is granular sodium bisulfate, which makes dilute sulfuric acid rather than hydrochloric acid, but it will work just fine for pickling.  Just a little slower than HCL.