What You Need To Know About PVC

[physics-fan3.14]

Or, PVC and You

 

I got authorization from supertooth (the godfather of WYNTK) to make this a WYNTK thread.

 

PVC is a plasticizer used to soften plastics and make them more pliable. Poly Vinyl Cholride is the full name for it, and it's chemical formula is

 

 

The brackets just mean that it is a continuing chain, hence the poly - a polymer is made up of indivual molecules that have undergone polymerization, that is, they have become linked together to form a chain that can be extremely long. Some polymers have individual molecules that weigh many grams or even kilograms. PVC is a simple polymer, based on your standard hydrocarbon, one of the Hydrogen atoms has been replaced with a Chlorine atom.

 

PVC was first made (accidentally, like so many other useful things) by a German chemist in 1912. His company patented it, but had no idea what to do with it. It wasn't until after their patent ran out that a chemist at BF Goodrich independently discovered PVC in 1926, and came up with the idea to make shower curtains out of it.

 

PVC is bad for coins because over time, it releases Hydrochloric Acid which eats into the surface of the coins. Hydrochloric acid is very dangerous, yet essential to life as it is the acid in our stomachs which dissolves food (if mixed with bleach, it also produces deadly chlorine gas). PVC was first made by reacting acetylene with Hydrochloric acid, so it only makes sense that HCl could be precipitated back out from it. PVC residue will manifest as a green, or sometimes brown, film or buildup on the surface of the coin. You can immediately tell it is PVC by smelling the coin: if it smells like a shower curtain, you can be certain that there is PVC present.

 

If your coin is affected by PVC, don't immediately panic. It takes some time for the PVC to do irreversible damage to a coin. An acetone bath will dissolve any PVC residue. If it hasn't eaten into the surface of the coin, it should be indistinguishable from an unaffected specimen.

 

 

Mylar flips are safe for coins. It is very difficult to distinguish a Mylar flip from a PVC flip just by looking at them. Try bending and folding a flip - if it is mylar it will feel more brittle. A PVC flip will feel more pliable. Also, try smelling the flip. Just like residue on a coin will smell like shower curtains, a PVC flip will sometimes smell like shower curtains. This is not foolproof, so do not use this as a certain test. The best way to be sure you are using Mylar or some other safe plastic is to note the box it came out of - it should say.

 

Another important consequence of using PVC flips is that the surfaces can become impregnated with particles, as detailed in this PCGS article. Apparently, the PVC flips attract microscopic particles which become embedded in the irregular surfaces of the flips. As a coin is slid in and out of the flip, these rough surfaces scratch the coin. While Mylar flips mitigate this problem, it is not completely eliminated. Therefore, care should be used when inserting and removing a coin from a flip, especially a PVC one.

 

Any flips I receive from dealers I treat as suspect, and usually throw them away. I never keep flips which I do not know the source of. While most dealers are conscious of the difference and the harms, you can never be sure. Also, you never really know how old the flip is - it might be from some old collection before these dangers became apparent.

 

It should be emphasized that PVC flips are usually okay for short term use. Various resources recommend limiting time to various amounts, but I would recomend not keeping them there for more than a month. The rate of Hydrochloric acid release is dependent on several factors, most important of which are temperature and humidity. Some coins have been stored in PVC for years and not been harmed, but others have been in PVC for a week and developed a film. This is especially noticeable on Proof coinage. Just be careful when using PVC.

 

Most of the people here know most of this information, but it is always good to review and remind people. Comment and discuss.

[rrantique]

Very informative post Thanks Physics-fan (thumbs u

[stinkycheese1]

Very nice thread indeed. If you leave gold coins in a PVC flip will the PVC react with the gold coin too?

 

All of my silver coins are in PVC flips and have been for years. I just dont have any (or very few) non-pvc flips

 

[TomB]

I wrote an article on PVC in 1998 so I am a bit familiar with this compound. This is trivial, but you have capitalized far too many words in your post such as chlorine, hydrogen and hydrochloric acid, which do not need to be capitalized within a sentence. I do not believe that under standard temperature and pressure that one would release acetylene and HCl from a PVC product. Rather, I believe ionized water molecules from the atmosphere, which form hydronium ions and hydroxyl ions, react with the chlorine in PVC to produce HCl.

[physics-fan3.14]

Very nice thread indeed. If you leave gold coins in a PVC flip will the PVC react with the gold coin too?

 

All of my silver coins are in PVC flips and have been for years. I just dont have any (or very few) non-pvc flips

 

Hydrochloric acid alone will not dissolve gold. However, if you add some nitric acid, it makes what is known as "aqua regia" which will dissolve gold. The chances of this happening are slim. The problem however is the fact that you probably store your gold coins in the same place as your silver coins. I would strongly suggest that you immediately discard your PVC flips, rinse everything in acetone, and purchase some mylar flips. They are only a couple of bucks, and the prevention of possible damage to your coins is worth it.

 

And Tom, yeah, I Capitalize too much, but I Like it, and it adds a certain Emphasis to key words.

[Yarm]

So are those soft pliable "polybags" also to be avoided for long term storage?

[cpm9ball]

So are those soft pliable "polybags" also to be avoided for long term storage?

 

I don't know for sure, but a couple of years ago I contacted the S. C. Johnson Co., the makers of Ziploc bags, and asked them if the bags contained PVC. Their reply was, "No".

 

Chris

[DC Dawg]

Or, What You Need to Know about PVC, an unauthorized WYNTK

Irrespective of the "excess capitalization" (sorry Tom, I don't agree), how do we nominate this for a WYNTK post? Arch... what say you?

 

Scott

[TomB]

I'm not certain why one wouldn't agree with the observation on excess capitalization since it isn't a matter of opinion, but of usage. You don't capitalize all nouns in your posts, do you?

[cpm9ball]

I'm not certain why one wouldn't agree with the observation on excess capitalization since it isn't a matter of opinion, but of usage. You don't capitalize all nouns in your posts, do you?

 

NO, i NEVER DO!

 

chris

[Conder101]

With age and heat PVC plastic can release HCl gas. The problem comes when the plasticizer that leaches out of the PVC plastic absorbs this gas and water vapor out of the air. The HCl and the water combine to form Hydrochloric acid which the plasticizer then holds in contact with the surface of the coin allowing the acid to work on the metal and corrode the coin.

 

If you leave gold coins in a PVC flip will the PVC react with the gold coin too?

The acid will not react with the gold, but if the coin is showing copper spots then the acid may react with the exposed copper. This may result in rough patches on the coin under magnification.

 

All of my silver coins are in PVC flips and have been for years.

On this point you are running a risk. One thing you can do to reduce the chances of damage are to keep the coins stored in a very dry environment. (low humidity) The reaction requires water to proceed. Eliminate the water and the reaction stops. If you see that your coins are developing a green oily film on them get them out of the flips and rinsed in acetone immediately. The green indicates that there is acid in th film and it is reacting with the copper in the alloy to form Copper Chloride which is green in color.

[physics-fan3.14]

So are those soft pliable "polybags" also to be avoided for long term storage?

 

I don't know for sure, but a couple of years ago I contacted the S. C. Johnson Co., the makers of Ziploc bags, and asked them if the bags contained PVC. Their reply was, "No".

 

Chris

 

I did the same thing, actually. They said that PVC was not FDA approved for sandwich bags (which makes sense), and any product intended for food storage will not have PVC.

[DC Dawg]

I'm not certain why one wouldn't agree with the observation on excess capitalization since it isn't a matter of opinion, but of usage. You don't capitalize all nouns in your posts, do you?

ME? NEVER!!!!

[cpm9ball]

I'm not certain why one wouldn't agree with the observation on excess capitalization since it isn't a matter of opinion, but of usage. You don't capitalize all nouns in your posts, do you?

ME? NEVER!!!!

 

sCOTT, yOU should never capitalize qUESTION mARKS and eXCLAMATION pOINTS.

 

cHRIS

[Connecticoin]

It should be emphasized that PVC flips are usually okay for short term use. Various resources recommend limiting time to various amounts, but I would recomend not keeping them there for more than a month. The rate of Hydrochloric acid release is dependent on several factors, most important of which are temperature and humidity. Some coins have been stored in PVC for years and not been harmed, but others have been in PVC for a week and developed a film. This is especially noticeable on Proof coinage. Just be careful when using PVC.

 

One should NEVER EVER use PVC flips, not even for a short period of time. Proof coins have been known to develop a haze just on the trip from the post office to PCGS on submissions. MS coins can eventually haze from a short stint in a PVC flip as well. Use non-PVC Mylar flips only, use mylar 2x2's, or hard plastic holders such as the capital plastics, Whitman snap-lock, Intercept shield, etc.

 

There is no reason whatsoever to use PVC flips anymore, and if there were a way to ban the sale of these, I would be all for it.

[pendragon1998]

I'd suggest that rather than sliding coins out of flips (particularly if the coin is destined for an album or some other non-flip destination), the user should just take a pair of scissors and cut the edges of the flip to remove the coin. Better to destroy the holder than damage the coin.

[Connecticoin]

I'd suggest that rather than sliding coins out of flips (particularly if the coin is destined for an album or some other non-flip destination), the user should just take a pair of scissors and cut the edges of the flip to remove the coin. Better to destroy the holder than damage the coin.

 

Good tip. That is what I always do with coins in flips and 2x2s. For 2x2s, I carefully cut the holder just inside the staple, then remove the coin. Removing the staples or pulling the holder apart can easily cause a staple scratch.

[Keleum]

Along the lines of flips, what about Vinyl pages for flips? Do those contanimate even though they dont touch the coin?

 

Is there a problem with Vinyl and currency?

[MikeKing]

 

And Tom, yeah, I Capitalize too much, but I Like it, and it adds a certain Emphasis to key words.

 

 

Like Capped Bust Halves

 

 

 

.....

 

great post!

[Oldtrader3]

Good article on PVC and it's chemical properties. Very useful information for all collectors. By the way, poly bags for food are normally made of extruded or blown extrusion polyethylene sheet. Polyethylene is safe for food and medical products as well. Rigid poly 2x2 "snaps" are also polyethylene, are inert and are good protection for any coins.

 

Please be aware that the rolls of flips that you buy from PCGS are also PVC. I have had 90% silver coins form a corrosive film and start blooming small HCL corrosion spots in PCGS flips that were stored in a closet, even for fairly short periods of time. I always place coins for submission into small poly sleeves and then fold and put the sleeves into the PCGS flips before mailing coins for grading.

[pendragon1998]

I'd suggest that rather than sliding coins out of flips (particularly if the coin is destined for an album or some other non-flip destination), the user should just take a pair of scissors and cut the edges of the flip to remove the coin. Better to destroy the holder than damage the coin.

 

Good tip. That is what I always do with coins in flips and 2x2s. For 2x2s, I carefully cut the holder just inside the staple, then remove the coin. Removing the staples or pulling the holder apart can easily cause a staple scratch.

 

 

For 2x2s, I put on a pair of disposable nitrile gloves (I'm allergic to latex) and use an X-acto knife to punch a pinhole through both sides of the window. Then, I just pinch the coin carefully and twist the 2x2. The windows tear easily and the coin is free.

 

The nitrile gloves are cheap as dirt and I use them for all sorts of things around the house, like preparing raw meat in the kitchen (yuck) or cleaning the bathroom. I can't use regular "rubber" (latex) kitchen gloves anyway, so the nitrile gloves work well for me.

[cpm9ball]

I'd suggest that rather than sliding coins out of flips (particularly if the coin is destined for an album or some other non-flip destination), the user should just take a pair of scissors and cut the edges of the flip to remove the coin. Better to destroy the holder than damage the coin.

 

However, if you are a McScrooge, you can use a pair of the plastic tongs to extract the coin from the flip. Just apply slight pressure on the outer sides so that the flip bends outward, thus reducing the contact with the coin.

 

Chris

[Mark T]

Has anyone seen what strong acid does to a coin ?? My dad is a pharmacist. When I was a kid I would ask him to poor acid on pennies to see the result. He would use either hydrochloric or sulfuric acid. As a kid I thought the result was “cool”. Obviously the acid ate away any junk on the coin and left it red from what I remember. I loved science when I was kid , do you guys my age remember those chemistry sets you could get when you were a kid back in the 60’s ?

[Coin]

Has anyone seen what strong acid does to a coin ?? My dad is a pharmacist. When I was a kid I would ask him to poor acid on pennies to see the result. He would use either hydrochloric or sulfuric acid. As a kid I thought the result was “cool”. Obviously the acid ate away any junk on the coin and left it red from what I remember. I loved science when I was kid , do you guys my age remember those chemistry sets you could get when you were a kid back in the 60’s ?

 

My dad wasn't a Pharmacist , so we had to use kitchen acid to play with our stuff. You know , the acid that is in foods . But as far as those awesome chem sets....dude , you could really blow stuff up with those! Too bad the ones they sell now wouldn't interest a kid in anything scientific , and would probably bore them into doing drugs for fun . WE had the 'survival' mindset as kids in the 60's and 70's ....kids today couldn't make flashlights that run on a potatoe , use a N134A diode and copper wire to make a radio set , and the plethora of MacGiver-type stuff we had to come up with .....because we couldn't just run down to a local Wal-Mart .

 

See my old post on Ketchup-hobo cents !

 

http://boards.collectors-society.com/ubbthreads.php?ubb=showthreaded&Number=1638076

[Houston Investor]

I have dipped badly greenish gooey PVC coins and had them bring MS 65 at PCGS. The dipping certainly did not restore nice luster by any means but average luster with few marks can still make MS 65 I guess.

 

So I will give you one guess why I laugh and laugh when someone wants to spend good money or time fretting about crossing over stuff to PCGS, especially if it brings a lower grade!

[pendragon1998]

Wow, old thread!

 

 

Here's another tip. If you're not sure if a flip contains PVC (e.g., you got a big box of them for free, but you don't know the material used in them), here is an easy test:

 

(Probably best done outside or with good ventilation; Avoid inhaling the fumes as they may be toxic.)

 

Take a piece of copper wire or a pre-'82 cent, hold it with a pair of pliers, and heat the other end up in a propane torch or cigarette lighter until it's very hot and the flame burns clear (removing any residue on the copper). Pierce the suspect flip with the hot wire, making sure to melt a little material onto the wire. Now, hold the wire back into the flame and allow the material on the needle to burn off. The flame will change color as the material burns off. If the flame turns green, then the material contained PVC. That's a very simple flame test like you would have probably conducted in a high school chemistry class.

 

If you're feeling frisky, here are some more flame tests for plastics:

http://www.boedeker.com/burntest.htm

 

Don't burn yourself; don't kill yourself; don't do this if you're not an adult; do this at your own risk; etc.

[MunkyMan95]

Or you could just smell them. If it smells like shower curtains, it contains PVC.

[pendragon1998]

The 'smell test' doesn't always yield a result if the flips are old enough to not have much residual odor.

[ant]

heck ive got problems with my nose and i have to ask my girl to smell the milk