Altered Surfaces - Removing Lucite?

[Zoins]

Another thread mentioned the Martha Washington patterns which I looked up on uspatterns.com. It mentions a number of these are at the Smithsonian in a blue lucite block and includes the following quote:

My Secretary of the Treasury, Joe Fowler, is a little stingy about making samples, but I have some here. Joe made sure that I wouldn't put them in my pocket by sending them over here in plastic.

This got me thinking. Given that plastic melts at a lower temperature than metal, is it possible to melt lucite off an entombed coin? Will the coins be ruined in the process?

 

Is there any good way to remove lucite from a coin?

[MunkyMan95]

I suspect that there is a chemical that would dissolve the lucite. What it would do to coins though, I don't know.

[pendragon1998]

Someone at this link had the same question:

 

EXTRACTING COINS EMBEDDED IN LUCITE

 

Johnson writes: "To comment on Stephen Pradier and

Ralf W. Böpple’s item in last week’s E-Sylum: The toilet

seat embedded with coins has been around for 40 years.

while there are hundreds of American firms that do Lucite

embedments, not all of them have the mold – called "forms"

by these firms – of the toilet seat. The most common forms,

of course, are cubes and disks and such.

 

You CAN retrieve a coin or medal once it is embedded in

Lucite. At Medallic Art, where I once worked, we had medals

embedded in Lucite if that is what the customer wanted.

I got an inquiry once "How do I get the medal out of the

embedment?"

 

I called the best authority possible: the DuPont Company,

which makes Lucite. Some nice man in their public relations

department told me how:

 

Use a band saw to cut the Lucite as close to the coin or

medal as possible (without, of course, cutting into it).

Chip away with hammer and chisel even closer. Then dissolve

the remaining Lucite in warm galactic acetic acid. I Googled

"galactic acetic acid" only to learn it is found in space.

(Now I wonder if he was pulling my earth-bound leg.)

 

I'm wondering is what the guy actually told him was glacial acetic acid, which is pure (water-free) acetic acid - like the stuff in vinegar, only about a gazillion times stronger. That said, I suspect that once the lucite is dissolved, you're going to run into problems with the surface of the coin being exposed to such concentrated acid - it'd be like a dip solution, but much, much stronger. It'd probably ruin the surfaces.

 

Your question about melting the lucite off could be somewhat better for the coin (possibly dissolve all but a thin layer off first). I don't know how you'd get the melted goo off the coin though - possibly with a high pressure air spray from a compressed air source? I don't know that I'd want to be anywhere near gobs of flying molten lucite, though. Sounds dangerous.

 

My guess is the coin is permanently encased, lest it be badly damaged by the removal. I wish they hadn't done the lucite trick in the past

 

NOTE: This is all hypothetically speaking on my part based on educated guesses.

[MrSpud-migration]

Wikipedia implies that lucite can be dissolved. It says "liquid di- or trichloromethane to dissolve the plastic" in a section that discusses how to fuse or weld pieces of it together. See Link

[Conder101]

I haven't tried it but I would suspect that removing it wouldn't be too difficult. The method I would suggest is:

 

Use the band saw to remove most of the plastic. Then use a pair of tongs to dip the coin into liquid nitrogen. The sudden thermal shock should cause most of the plastic to break up and fall away from the coin. If any remains stuck let it return to room temperature and then run through a few cycles of dipping in the nitrogen and letting it warm back up. The rates of expansion and contraction are very different for the two materials and it should cause the last traces of plastic to lose their "grip" to the coin. (The plastic shinks faster, but the metal shrinks more. This puts great stress on the plastic/metal bond.)