Remove gold from plastic?

I am no a jeweler or chemist. I have a small pin made of a plastic dated =
to the
early 1940=92s. It is gold plated (?) and badly worn in spots. Can the go=
ld be
removed? TIA

On Wed, 01 Jun 2005 18:56:09 -0700, in ¸õ "Lorraine" wrote:

I am no a jeweler or chemist. I have a small pin made of a plastic dated
to the early 194's. It is gold plated (?) and badly worn in spots. Can the gold be
removed? TIA

Plastics can be buffed and polished in many cases, and this would do the trick if
what you're trying to do is clean up the plastic by removing the worn gold.
Whether this works depends on the type and hardness of the plastic, but there are
buffing compounds made for hard plastics like plexiglass/acrylic, and these may
well work just fine. For some items, very fine wet/dry emery paper (600 or 800
grit), used with water, will give a uniform matte finish, that can then be buffed
easily, even by hand, with those compounds on a cloth, or it may be nice just left
with the matte surface. This requires a shape to the pin that can be properly
buffed. If highly detailed, that doesn't work.

In that event, it may be possible to chemically remove it, but the chemicals
involved, if the plating is actually gold, are nasty. You're choice of cyanide
solutions, aqua regia (a mix of hydrochloric acid and nitric acid) unless the
gold is plated over a more reactive under plate, in which case simpler and less
dangerous acids and acid concentrations might be able to attack the underneath
plating layer thus freeing the gold. Can't tell that without looking. If it's
actually electroplated, this may be the case, but much gold surfaced plastic, even
from the 40s, is done by direct vapor deposition methods, and then an underplate
is not needed. If the gold surface is intact enough to be still fully
electrically conductive, then reverse electroplating (called electrostripping)
might be an option. Again, hard to tell without seeing the piece.

If you're trying to reclaim the gold value, don't bother. Unless you have pounds
of these things, the cost of recovering the gold exceeds the value. If you DO
have pounds of it, the best bet is sending it to refiners equipped for such low
gold content materials.

You should also be aware that merely looking like a gold plated surface is not a
guarantee that the plated metal actually IS gold. There are a number of plating
types with a similar yellow color that are not gold. If your piece is plated with
one of those, the above info may be incorrect in that it may be easier to
chemcially remove (acid etch) the coating.

You might also try an ultrasonic cleaner. If the plastic is sturdy enough, it
might be possible to just leave it in an ultrasonic (a commercial qualtiy, not the
small home machines) cleaner for a while. These have enough energy to be able to
damage and possibly remove after some time, thin electroplated surfaces in some
instances. Be sure the cleaning solution is cold enough so the plastic won't be
damaged by heat, as some ultrasonics have heated tanks, and these can get hot
enough to damage some plastics.

Hope that helps.

Peter Rowe

"Peter W.. Rowe," wrote in message
...
On Wed, 01 Jun 2005 18:56:09 -0700, in ¸õ "Lorraine"
wrote:

I am no a jeweler or chemist. I have a small pin made of a plastic dated
to the early 194's. It is gold plated (?) and badly worn in spots. Can the
gold be
removed? TIA

Plastics can be buffed and polished in many cases, and this would do the trick
if
what you're trying to do is clean up the plastic by removing the worn gold.
Whether this works depends on the type and hardness of the plastic, but there
are
buffing compounds made for hard plastics like plexiglass/acrylic, and these
may
well work just fine. For some items, very fine wet/dry emery paper (600 or
800
grit), used with water, will give a uniform matte finish, that can then be
buffed
easily, even by hand, with those compounds on a cloth, or it may be nice just
left
with the matte surface. This requires a shape to the pin that can be properly
buffed. If highly detailed, that doesn't work.

In that event, it may be possible to chemically remove it, but the chemicals
involved, if the plating is actually gold, are nasty. You're choice of
cyanide
solutions, aqua regia (a mix of hydrochloric acid and nitric acid) unless the
gold is plated over a more reactive under plate, in which case simpler and
less
dangerous acids and acid concentrations might be able to attack the underneath
plating layer thus freeing the gold. Can't tell that without looking. If
it's
actually electroplated, this may be the case, but much gold surfaced plastic,
even
from the 40s, is done by direct vapor deposition methods, and then an
underplate
is not needed. If the gold surface is intact enough to be still fully
electrically conductive, then reverse electroplating (called electrostripping)
might be an option. Again, hard to tell without seeing the piece.

If you're trying to reclaim the gold value, don't bother. Unless you have
pounds
of these things, the cost of recovering the gold exceeds the value. If you DO
have pounds of it, the best bet is sending it to refiners equipped for such
low
gold content materials.

You should also be aware that merely looking like a gold plated surface is not
a
guarantee that the plated metal actually IS gold. There are a number of
plating
types with a similar yellow color that are not gold. If your piece is plated
with
one of those, the above info may be incorrect in that it may be easier to
chemcially remove (acid etch) the coating.

You might also try an ultrasonic cleaner. If the plastic is sturdy enough, it
might be possible to just leave it in an ultrasonic (a commercial qualtiy, not
the
small home machines) cleaner for a while. These have enough energy to be able
to
damage and possibly remove after some time, thin electroplated surfaces in
some
instances. Be sure the cleaning solution is cold enough so the plastic won't
be
damaged by heat, as some ultrasonics have heated tanks, and these can get hot
enough to damage some plastics.

Hope that helps.

Peter Rowe

Thank you Peter Rowe for the detailed explanation.

I'm [trying] to assemble a collection of the WW2 Honorable Discharge pins or the
"Ruptured Duck" as it they were called. My hope was to put together a history of
this item but that's beginning to appear impossible at this late date. I believe
all pins were real gold plated put purity or types of plating are probably
speculative and/or lost in time. Originally made of a plated metal, during the
metal shortage [believe it or not] in 1943, these pins were constructed from a
dark plastic and later, when it was realized that these pins were not
discernable against dark suits, change to gold-plated plastic. I have a few
plated plastic pins but have never seen nor found a plain plastic pin. I have
pins, which are badly worn and show signs of plastic so I thought maybe they
could be the dark plastic under the plating and I wanted to look. If you never
saw one of these pins they were basically:

Given for Honorable Service from 8 Sep 1939 through 31 Dec 1946. A gold color
metal lapel button 7/16 inch in height and 5/8 inch in width, a dexter eagle
with wings displayed perched within a ring which displays thirteen vertical
stripes with a chief, the dexter wing of the eagle behind the ring, the sinister
wing in front of the ring.

Buffing or sanding would obliterate that detail so it was necessary to find a
chemical solution. Not being knowledgeable in chemistry I tried various
household products without success. All I accomplished was discovering that gold
isn't easy to remove even thin plating. I placed a pin in muriatic acid for a
few days and that destroyed the plastic.

Issued by the US government to eligible WW2 veterans I would guess they were
gold but that is only my supposition as the official description states "a gold
color metal." The original pin base material was possibly silver or
silver-plated metal, "some" are marked sterling and all are gold color although
I do have a sterling silver pin. I have seen many that had been well used and
consequently worn through the gold exposing some silver.

I learned much from your reply and wish to express my thanks for taking the time
to answer my question so explicitly.

Lorraine