PVC damage: Urban myth?

MrEureka

I've looked at MILLIONS of good coins in the past 25 years. I know what PVC residue looks like when it sits on a coin. I've seen more than a few thousand coins with PVC haze and/or spots. I've even seen hundreds dripping with emerald green liquid PVC. I've removed PVC from well over a thousand coins. I've worked in the PCGS grading room and I bodybagged many coins for PVC residue.

With all that experience, I still don't know what PVC damage looks like. Do you? Have you SEEN it? Or is it just another urban myth?

eureka

I've never noticed any damage after PVC removal. Verdigris, however, is another story. I think people sometimes think they are the same.

Russ

Freaky. Two Eurekas.

Andy,

Now that you mention it, I've never seen any perceptible "damage" after PVC removal either. Of course, I haven't done any where near the coins you have, so my experience really isn't enough for me to form a personal conclusion.

Russ, NCNE

MrEureka

Can the chemists among us explain what PVC does to the surface of a coin?

eureka

Even more strange, I'm also Andy. hehe

lordmarcovan

Hmm. OK, you've got me, there. I've seen some nasty green goop, but never any actual damage resulting from it. A little acetone and/or Jeweluster, and I was on my way.

Maybe it's something invented to sell more inert flips and such?

Perhaps someone with the requisite chemical/metallurgical knowledge will weigh in on the question.

Placid

I think the damage is the pvc itself. Its ugly

coinkat

I am not a chemist, but PVC does cause damage to the lustre and can leave an ever so slight etching on the surface that really impairs the coin. Flips should never be used for long term storage for any coin.

darktone

I agree with coincat. I have acetoned silver coins only to have spotting left from where the PVC sat. mike

MadMarty

Like this maybe!

1jester

There have been a few threads wherein the nature and action of PVC was clearly explained. Someone can probably do a search for those threads here on this forum.

I have indeed suffered extensive damage to a bunch of very high grade silver coins, and after acetone was used to wash off the PVC, there were serious craters on the coins. It was a disaster. The coins had been sitting outside, in a shed, near the beach in Fernandina Beach Florida, for about 5 years. So the combination of heat, humidity, salt and PVC combined to utterly destroy the surfaces of many investment grade coins, including many DMPL Morgans, including some CC dates. All in MS-63 to 66 condition. What a disaster. Incidentally, some coins which were in mylar albums, and mylar 2X2s suffered absolutely no damage under the same conditions.

So don't believe it's a myth. PVC turns to hydrochloric acid which in turn literally eats away at the coin.



PS: Don't ask me why my dad left my collection out there.

1946Hamm

Here is a picture of PVC damage. I bought a partial set of coins that had been in an old coinmaster type album and all the coins had active PVC on them. I used acetone to rid the PVC but the damage was evident on the best coin in the group. As you can see the luster was all but elimated on the area on the right side. The break in the luster on the right side is where the PVC was. It's a shame on what I think is a nice coin.

This is my first post but thought I had some info to share.

Gary

LanLord

I have a Delaware Commemorative half dollar that I cleaned PVC off, and on the back, on the highpoint of the sail, there is a spot where the metal is definitely etched. I always assumed it was PVC that caused it, but it could have always been there prior to the half being placed into the PVC flip.

See spot in middle of sail.

Barry

<< <i>Can the chemists among us explain what PVC does to the surface of a coin? >>


I recall reading somewhere that the chloride ion in poly vinyl chloride reacts with water vapor in the air, resulting in hydrogen chloride, aka hydrochloric acid. Makes sense to me (though I'm not a chemist, but 2 1/2 years of chemistry in college).

lordmarcovan

Gary- nice first post. Welcome!

(Geez... a newbie who knows how to add an image to his post! What is this place coming to??)

There. Marty finally shared the "Magic Crystals Lincoln Cent" again. I begged him to post it on one thread, a while back, but he didn't humor me. Hmm... maybe I should steal the pic... bwahahahaha

1jester

Welcome to the forums, Hamm!!!

1jester

I'm just incredibly disgusted and frustrated that PVC is even sold at all. I wonder why it exists, and why the ANA or other organizations don't do their utmost to make sure that poison is completely removed from the market. It's like radioactive isotopes floating around everywhere, or AIDS, or hantavirus, or anthrax, or....you get the picture. Why do we allow it to even be sold??

fcloud

I don't have a photo, but I had a bunch of BU Mercury dimes sit in bad holders for about 15 years. I didn't know what PVC was. After getting some acetone to remove the PVC, I looked at the coins under a glass. There is craters in the metal from the PVC. Real Craters!

LanLord

<< <i>I'm just incredibly disgusted and frustrated that PVC is even sold at all. I wonder why it exists, and why the ANA or other organizations don't do their utmost to make sure that poison is completely removed from the market. It's like radioactive isotopes floating around everywhere, or AIDS, or hantavirus, or anthrax, or....you get the picture. Why do we allow it to even be sold?? >>

I don't know if you mean to get rid of PVC altogether or just in the coin world.

PVC is a very useful thermalplastic used in many processes within the electronics industry. It's ability to withstand contact with certain acids make it very much in demand in the etching industry (Printed Circuit Board manufacturing) as well as in the plating industry (used in manufacture of solid state chips).

We could get by without it, but the alternatives would be a great deal more expensive such as Teflon and PVDF (Poly-Vinylidene Floride), in some cases Polyethylene - but it won't withstand some of the nastier acids.

1jester

Fcloud, I know what you're talking about. I too never heard of PVC or the damage it could cause, 15 years ago. I thought I was doing the best I could for my coins.

I'm afraid before it's over with there will be huge casualties in the coin population from PVC damage. It's just so sad to me that coins survived intact, even in mint state, for 50-100 years or more, only to be ravaged by the very preventable carnage of PVC. WHY oh WHY did some unscrupulous PVC sellers/producers heave this immense travesty on coin collectors??

Edit: I'm talking about PVC for numismatic purposes. I realize PVC has its uses outside the coin collecting world.

LanLord

1Jester, in that case I completely agree with you.

crito

This coin was sitting in a PVC holder for a few decades. Believe it or not, it was uncirculated.



Before and after the acetone bath. Didn't help much at all, the coin is ruined.

Conder101

Ok, here is the run down again on how PVC damage occurs.

The plasticizer leaches out of the PVC flip. (The plasticizer is an oil which makes the plastic flexible. PVC by itself is a rigid and somewhat brittle.)

As the plastic ages it begins to break down some and starts outgassing Hydrogen Chloride gas. Some of the gas dissolves into the plasticizer that leached out earlier. Heat greatly accelerates the aging/outgassing process.

The plasticizer also absorbs water vapor from the atmosphere. The water vapor and the Hydrogen Chloride combine to create Hydrochloric acid. The oil acts to hold the acid in close contact with the metal of the coin.

The reaction of the acid with the metal of the coin results in the creation of silver chloride which is white in color (this may be the source of the hazing seen on silver coins, especially proofs.) and copper chloride which is green and is the source of the color in the "green slime".

The eventual result of this acid contact is an etching of the surface of the coin.

fivecents

PVC damage is not a urban myth. I have seen extreme PVC damage literally eat into the surface of a coin. It all depends on how long the PVC has been on the coin or the tempeture the coin was stored. I still can't beleive PVC flips (poly-vinyl) are still being sold and used. If coins are stored long term in these flips they WILL become PVC contaminated. These polyvinyl flips have killed and are killing alot of great coins. I blame the coin supply business for this. For some reason toned coins resist the PVC where the white coins don't. The toning seems to be a barrier of protection.