Before and after PVC removal on 1883 Hawaii half dollar

theboz11

Got this recently and noticed PVC damage and desided to soak it for awhile. Well the coin also appeard to have some other crust on it that looked like fire burn resin, which desolved it the soak. The coin that came out was remarkably frosty with prooflike fields in portions of the reverse. The only stains left on the coin are very deep blue from the heat of the wood that had burned on it. I can actually cartwheel the luster.


Before




After

DeutscherGeist

I heard we were never to dip our coins

Seriously, though. Did you put the coin in acetone and let it sit for awhile? Is PVC damage really reversible?
I made a lot of mistakes on my first few silver coins, but now I only handle them with 100% cotton gloves.

theboz11

I went a little stronger than actetone and used MEK, methel-ethyl-ketone. I DO NOT RECOMMEND anyone do it without proper knowledge of how dangerous this stuff is. The fumes will eat your liver, but it's purpose is to soften Vinyl for repainting. It is not reactive to metal, just like acetone. Yes this stuff and acetone will reverse the damage. The photo shows that

MrEureka

There's a difference between PVC and PVC damage. If the PVC comes off leaving no underlying problems on the coin, I think it's safe to say that there was no PVC damage.

As for how to recognize PVC damage, I'm not quite sure. Maybe somebody can enlighten us.

Hyperion

interesting....

BBQnBLUES

IMPRESSIVE results !!

Now you need to let this coin re-tone in a Taco Bell napkin

7Jaguars

PVC is "polyvinylchloride" which is chemical shorthand for a whole family of plastics that have now been around for decades. The plasticity in many plastics including many coin holders is given them by these substances. They have halides which include as a family chlorides as part of their chemical structure - this gives the "flexy" but not crisp type of holder that we know. Mylar and similar plastics are crisper and more "crackly".

The PVC plastics degrade and sweat off hydrocarbons with these chlorides which further break down; gives them a green color and oily residue to surfaces they have been deposited on. If these chlorides stay in contact with the coin surface long enough they will begin to oxidize or corrode the surface. Sorry to say I do not know have the capability of sending pictures.

Even when the oily "crud" is removed from the surface of the coin with acetone or other solvents, the PVC breakdown products may actually then break down the metal surface of copper and silver coins, or obviously more reactive metal coins such as aluminum or zinc or steel....

Sorry about the blah, blah, blah...

Hyperion

excellent description of the physical processes involved.....

enlightening!

zeebob

<< <i><snip>Even when the oily "crud" is removed from the surface of the coin with acetone or other solvents, the PVC breakdown products may actually then break down the metal surface of copper and silver coins, or obviously more reactive metal coins such as aluminum or zinc or steel....<snip> >>



So are you saying don't wash the gunk off?

I have had mixed results with slimmed coins. I ran some chinese coppers through acetone only to find that the surfaces were pitted and there was green corrosion under the PVC. I wish I had taken photos before and after. I'm not certain that the coin didn't corrode as part of the PVC removal.

I'd be interested to hear more.

7Jaguars

Wash the gunk off! If not corrosion/oxidation will proceed. Sometimes the surface on copper will have a stripped appearance as the PVC/metal complex has given the coin its patina.

On a few Roman bronzes I have seen the coin to look worse after cleaning, but mostly you want to get rid of the offending agent.

SYRACUSIAN

<< <i>There's a difference between PVC and PVC damage. If the PVC comes off leaving no underlying problems on the coin, I think it's safe to say that there was no PVC damage.

As for how to recognize PVC damage, I'm not quite sure. Maybe somebody can enlighten us. >>





Coin resembles face with prior heavy acne problems?

1jester

Boz, good job getting that junk off the coin! It looks nice now.

Unfortunately I no longer have my large scans of several PVC damaged Morgan dollars, but I do have some very small scans. It's hard to tell on the 1878-CC DMPL dollar, and easier to see in the 1885-O dollar, but if you look hard in what should be even fields, you can see the spots/freckles which are in fact craters that if they were in your teeth would need fillings!! PVC damage exists as soon as the PVC reacts and turns to hydrochloric acid and eats into the coin. The oily film that develops on the coins when they are in contact with PVC is the first symptom of PVC poison, but if caught in time and removed, the coin might be saved without damage.








I still think dealers who use PVC products should be strung up at high noon.

theboz11

It's much easier to see on proof fields than anywhere else, between that and spital marks from some clod blowing the dust off his coin with his breath, I don't know what upsets me more about careless handling of old coins.

MrEureka

This thread is about to get interesting!

MrEureka

I'm waiting...

MrEureka

Come on, I can't be the only one...

spoon

<< <i>It's much easier to see on proof fields than anywhere else, between that and spital marks from some clod blowing the dust off his coin with his breath, I don't know what upsets me more about careless handling of old coins. >>

Ha! Probably more than half of the dealers I came across in Europe handled their coins in ways that would make you cringe! Just pull it out of the tray, here, you want a closer look? Fingers all over everything...

And then there's our old favorite, what was his name? the kid who chiseled something off his gold coin and gave the forum a month of nagging misery...

lasvegasteddy

m.e.k.
awesome stuff...i about cried when cal-osha banned it from cali machine shops

sinin1

I think you bought a fake

a couple blebs coming from the fields were they should not be


edit to add just saw article in coin world about these

hope you did not pay too much

theboz11

I just got the wake up call I received my CW yesterday.

Fortunately I know the seller and a refund is already arranged. Even the most experienced buyers and sellers do not know all the counterfeits out there. A reason that I keep telling NEWBIES that good books on counterfeits will save them a lot of money in the long run. With all the new Chinese stuff out there, it will be a must have knowledge to survive coin collecting.

Like most people here, I "assumed" that the seller knew how to spot a fake from a small series, not in his field of expertise. It is a lesson for all to heed when buying outside of YOUR area of expertise, like I did.

Don't "ASSUME", KNOW!


At least the thread provided conservation tips for fire burned coins

1jester

<< <i>

<< <i>It's much easier to see on proof fields than anywhere else, between that and spital marks from some clod blowing the dust off his coin with his breath, I don't know what upsets me more about careless handling of old coins. >>

Ha! Probably more than half of the dealers I came across in Europe handled their coins in ways that would make you cringe! Just pull it out of the tray, here, you want a closer look? Fingers all over everything...

And then there's our old favorite, what was his name? the kid who chiseled something off his gold coin and gave the forum a month of nagging misery... >>



You got that right, Spoon. The way most (even the most reputable European dealers) handle (literally as well as figuratively) coins is absolutely deplorable. Not to mention their use of PVC.

DoubleEagle59

<< <i>I went a little stronger than actetone and used MEK, methel-ethyl-ketone. I DO NOT RECOMMEND anyone do it without proper knowledge of how dangerous this stuff is. The fumes will eat your liver, but it's purpose is to soften Vinyl for repainting. It is not reactive to metal, just like acetone. Yes this stuff and acetone will reverse the damage. The photo shows that >>



I've never used this stuff but it does sound highly toxic.

I would therefore recommend using it only if you have access to a fume hood.