Removing Lead Solder From Gold Coin (2nd try)

Have a question or want to show off your project? Post it! No Registration Necessary.  Now with pictures!

Threaded View
(I tried posting this last night from home, but was probably stymied
by the fact that I have changed my system date to prevent W7 from
crashing. Apologies if this is a repeat.)

On another list I read (about coining), someone asked if it is
possible to remove some lead solder from a gold coin. I thought of
using an acid that would dissolve the tin and lead, but what would
that be? Also, would any such acid leach out the alloying metal from
the gold, and would that change the color of the coin?

The coin is a 2 1/2 dollar US piece, in otherwise good condition, so
abrasive removal would probably not be a good option.

I'm not involved in this, but it seems to be an interesting problem,
and if anyone has a workable solution, I'll be glad to pass it on
(with attribution) to the OP.

Thanks,
Joe


Re: Removing Lead Solder From Gold Coin (2nd try)
How about asking a jeweler?

i

Quoted text here. Click to load it

Re: Removing Lead Solder From Gold Coin (2nd try)
responding to
http://www.polytechforum.com/metalworking/removing-lead-solder-from-gold-coin-2nd-try-193323-.htm
, hony wrote:
Hiii friends...
 
Best way to remove lead solder from Gold...
 
http://www.crockogold.co.uk/leadsolderremoval.htm  
 
Thank you,

Re: Removing Lead Solder From Gold Coin (2nd try)
On 10/13/2012 1:18 PM, hony wrote:
Quoted text here. Click to load it

That doesn't have anything about how to remove solder.

Re: Removing Lead Solder From Gold Coin (2nd try)
On Thu, 06 Aug 2009 08:51:34 -0400, Joe wrote:

Quoted text here. Click to load it

A quick bit of looking on the web suggests that

a) quarter-eagles are 90% gold / 10% copper; and

b) tin-lead solder can be removed from copper with a solution of 33gm
acetic acid and 50 gm hydrogen peroxide in 1 litre of water; and

c) acetic acid WITHOUT any nitric acid will not dissolve gold

so what I'd do, if minded to do this on my own, would be to remove as much
solder as possible with heating and wiping/wicking, then make an
appropriate solution and watch it.  Remember that common white vinegar is
only 5% actice acid, so you'll have to do a bit of extra maths.

Re: Removing Lead Solder From Gold Coin (2nd try)
Quoted text here. Click to load it

Seems like metallic mercury will remove the lead and not the gold.
Years ago, as a kid I used to play with mercury. It removed the lead
from the solder at the joint where the ring I wore had been resized.

Re: Removing Lead Solder From Gold Coin (2nd try)
Quoted text here. Click to load it

Oh, forgot to mention that mercury was used for years to remove lead
from firearm barrels after shooting soft lead bullets. Used to keep  a
bottle in my shop for this purpose.

Re: Removing Lead Solder From Gold Coin (2nd try)
On Thu, 6 Aug 2009 08:57:38 -0700 (PDT), Gerry wrote:

Quoted text here. Click to load it

Mercury dissolves gold.

If you had a ring that had lead solder joining it the rest of it probably
was not gold.

Site Timeline