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Melted plastic


#1

After lurking for some time I have decided to jump in with a problem.

INTRODUCTION: I have been in the jewelry business for 25 years now,
as a bench jeweler-repair person, salesperson and store manger. I
began my interest in jewelry in college. Afterward I worked for a
jewelry designer in New Orleans and then in Memphis at stores where
we manufactured most everything we sold, followed by 13 years in a
very up scale, carriage trade store. I am now managing and doing
repairs for a smaller mom and pop store. I have also taken GIA home
courses, and read numerous books on the subject. I think Orchid is a
wonderful resource!

The PROBLEM: This week one of our customers came in with about 30
pieces of jewelry melted into a blob of plastic. The customer’s house
had burned to the ground, the jewelry was in a safe, some of it was
in a plastic jar of jewelry cleaner, and some more was in clear
plastic divided trays. All of it ended up in one nasty lump. The
plastic is still mostly clear (it melted but did not burn) it is
fairly brittle, I have started breaking it up but at this rate some
pieces are sure to be destroyed if I don’t come up with a plan on how
to dissolve or remelt the plastic.

Any suggestions would be greatly appreciated

Danny Rumble @James_Rumble


#2

Hi James, I would start with Acetone. If that doesn’t dissolve your
plastic, then I would call a local chemical supply or industrial
chemical supply outfit and ask them if they have a solvent for
plastic. The problem you might face is that there are many types of
plastic and some solvents only work on specific plastics. Good luck, Will E.


#3

Danny- My first thoughts aRe: the plastics should melt(but smoke and
stink) in a burn out. I might try a burnout just below the melting
temp of the solders used in construction. A double thickness of
aluminum foil could catch the melt and be thrown out. This would also
best be done outdoors. Perhaps John Burgess would know of a chemical
melt, available. Curtis


#4

The worst case would have the plastic be polyethylene or
polypropylene. This can be melted but you probably won’t ever finish
getting it off. If it is polystyrene or acetate you could soak in
acetone, methylene chloride, or lacquer thinner (toluene or xylene).
Test and see if these work . Methylene chloride will probably be
the most potent If they do seal the mess up in a can and wait for the
mess to soften. A lot of the commercial paint removers are blends of
this and also include methanol. Be careful with the fumes!! Good luck
Jesse


#5

Many plastics will melt at temps between 200 & 400 deg. F. Your
melted lump containing the jewelry is proof.

Probably the simplest way to remove the encapsulated jewelry is with
heat. If it were me, I’d get a good heat gun (dual temp ones are about
$100). The heated air could be directed at a small section of the
’lump’ until it melts ors is softened enough to remove the jewelry.

You might try putting the lump in a pan in an oven. However, of the 2
procedures, the 1st allows easy observation of the melting and allows
removal of the jewelry with a tweezers.

Dave


#6

Hello James,

I think the plastic is of a polypropylene or polyethylene type, If
you burn it does it smell a bit like wax? There are solvents for
several plastics, but the are dangerous. But what you can do is, but
the lump in your house hold oven 150-200 degrees Celsius. and melt it.
The temperature depends on your plastic , if it is smoking a lot you
can turn the heat lower. Take the jewellery out the molten plastic,
and make the as clean as possible with a old cloth. Wear cloves it is
hot. After this you heat up the jewellery with contains still plastic,
with a flame, and burn it away. the black residue can easily removed.
you only need 300-400 degrees Celcius to do so.

Martin Niemeijer


#7

I’d suggest you subject this mess to various solvents, one at a time.
For instance, “attack” is a commercial product sold in jewelry
supply houses for removal of cured epoxy. It will also soften some
plastics. Acetone will work on other types of plastic. Paint
stripper may get at other plastics. If none of these work
individually, perhaps they’ll work in combination. Otherwise, you
might be able to physically extract some of the pieces by heating the
mass in an oven to a couple hundren degrees, below a temperature at
which it will burn, but hot enough to soften it. Put on a pair of
gloves and see if you can gently pry a few articles free. Good luck,
let us know how you fare on this project. Could result in some very
usefull research results.

David L. Huffman


#8

Hello Danny, You wrote

    The PROBLEM: This week one of our customers came in with about
30 pieces of jewelry melted into a blob of plastic. 

To begin, there are many different types of “plastic”. The original
form of the word, coined in the 1600’s, was the adjective meaning
formative or creative. We have subsequently adapted the word as a
noun. Why the pedantry? Because you need to know what type of plastic
your are dealing with; there are many organic compounds possessing the
attribute of plasticity. Once you know that you can then figure out
the appropriate course of action. I suspect that in some instances
that the jewellery is melted in an acrylic, something like
"Plexiglas". If that is true, then you can find the appropriate
solvent of polymerized acrylics, of which there are many. Your local
library might help, but better still might be the local college or
university where this knowledge will be readily available.

I used to use plastics to embed specimens for ultra-thin sectioning,
and occasionally we needed to remove the the polymer. In our case the
embedding material was “araldite”, but it is unlikely that this is
the material surrounding your work.

Hope this helps

David


#9
....The customer's house had burned to the ground, the jewelry was
in a safe..., All of it ended up in one nasty lump. The plastic is
still mostly clear (it melted but did not burn) it is fairly
brittle, 

G’day From your brief description of the plastic it seems to me that
it may be polystyrene, which melts at a fairly low temperature. It
did not catch fire as oxygen was excluded by the safe. Take a small
sliver of the plastic and holding it in forceps light it with a match.
If it burns with a very smoky, very pale yellow flame and the smell
of the fumes from it remind you of the two part plastic used to repair
dents in cars; a kind of aromatic smell, then it probably is
polystyrene. A number of solvents will dissolve polystyrene; benzene
(C6H6; not gasoline) toluene, xylol, and of course, whatever is sold
as thinner for ‘car dent bog’. Most of these solvents are fairly
poisonous and intoxicating, and should not be breathed any more than
essential. Work out in the open, preferably. Place the items in a
clean, empty lever-top tin, cover well with the solvent, replace the
lid tightly and leave for a day or so. On retrieval of the items they
should be well wiped, and perhaps will need a further treatment with
fresh solvent. By the way, these solvents will swiftly destroy latex
gloves, and some will even penetrate plastic gloves; take care not to
get any more than can be helped on the skin. The solvent will not
react with metals, but some porous stones, like turquoise, chrysocolla
and some opals will absorb solvent, but will release it on standing in
the open. Let us know how you get on. Cheers, – John Burgess;
@John_Burgess2 of Mapua Nelson NZ


#10

warning…when handleing these chemicals they can pass easily thru
the skin…wear gloves and drink plenty of milk during and after the
process…this absorbs the contaminants before they can damage your
liver…also have plenty of ventilation ringman


#11

Hello, One problem with burning many plastics is the production of
dioxin, known to be a carcinogen. Since the jewelry is probably in a
mixture of several plastics, just count on this being a problem. I’m
not sure about the melting of plastic creating “toxic waste”, but
please observe very good ventilation practices here.

Judy in Kansas Judy M. Willingham, R.S. Extension Associate 221 Call

Hall Kansas State Univerisity Manhattan KS 66506 (785) 532-1213
FAX (785) 532-5681


#12

James; As plastics are organic polymers they usually dissolve easily
in an organic solvent. I would try Acetone first as it used more or
less as a universal oraganic solvent. If the acetone fails I would
then use ether (much more dangerous and flamable than acetone) or
attack ( a comercial solvent for epoxies and such). If you really are
in no hurry and want to be environmentally safe I would try one of
the citrius based wax solvents that have been discussed here on
orchid. I use Rey wax gloss myself and have found that it will attack
some plastics. It all depends on the type of plastic. Hope this helps.
Frank Goss


#13
Hi James, I would start with Acetone. 

G’day; me again! Acetone won’t touch many plastics; It goes mostly
mostly for the cellulose based ones like cellulose nitrate (celluloid)
or methyl cellulose or cellulose acetate, (And you know that he who
acetates is lost. Bah!!) …

There’s a zillion plastics on the market these days, so for someone
to say “it’s made of plastic” doesn’t tell one much; rather like
saying “it’s made of metal” One thing I can say is that it can’t be
one of the waxy long chain plastics molecules like polyethylene or
polypropylene, for none of those are transparent; translucent but not
transparent. And nothing at all dissolves them. It isn’t a
thermosetting plastic either; none of those are transparent and they
smell of phenols when scraped. It might be an acrylic like perspex
(methyl methacrylate) which is transparent, and smells fruity when
heated or burnt. That dissolves easily in chloroform - which is also
an excellent adhesive for it. There’s a whole swag of plastics it
CAN’T be. It is however, most likely to be polystyrene which smells
of benzene when burnt, is completely transparent, and the solvents for
that are benzene, xylene and toluene. All of them have been labelled
as toxic. Cheers.