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 Replies: 13 / Views: 5,082 |
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Pillar of the Community
Australia
1364 Posts |
What I would like to know, is there any proof that PVC is detrimental to the storage of coins, both silver and bronze, over the long term?
I've been sorting through two albums of Australian pre-decimal and decimal coins that have been stored in albums since the 1970's and none of the coins show any evidence of contamination?
I store my main coins in 2 x 2 holders because I've read this is a safe alternative.
What about all the other spares I have though? I've tried hard to find an economical alternative to PVC holders but haven't had much success!
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Pillar of the Community
Sweden
1078 Posts |
PVC holders are fine just as long as the PVC is not in direct contact with the actual coin while in storage.
PVC contamination is a green, sticky residue and coins affected by it often have visible green residue on them, if not they are atleast notably sticky.
The only issue with 2x2 holders is that if old enough, they too can contain PVC. Newly bought ones rarely, if even at all, contain PVC.
There are plenty of album page holders that aren't made of PVC, most of these are more recent though. From my experience with going through old coin albums is that 9 times out of 10 they are made of PVC, especially from the 1960's and 1970's.
The deal with PVC is that when it's being squeezed, parts of the clorine seeps out and reacts with hydrogen to form hydrochloric acid, and this reacts with the surface of the coin stored in this environment. For copper and brass coins especially, the surfaces turn dark and dull. I don't remember the exact chemical reactions but it's a rough description of what happens, the results stay the same.
The issue with album holders and 2x2 is that none of them are air-tight, so coins will eventually tone and turn reddish while in storage. Adheasive flips are a cheap, somewhat airtight solution, capsules or proper coin holders (or 'slabs') are better for coin preservation but are also more expensive.
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CCF Advertiser
United States
1533 Posts |
Is the problem with the PVC or the phthalates used to soften them?
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Pillar of the Community
Canada
1747 Posts |
if you want an easy cheap way to store bulk coins use zip lock freezer bags, include in the bag a pouch of desiccant to help keep any humidity off your coins. these are pvc free
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Moderator
 United States
187702 Posts |
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Is the problem with the PVC or the phthalates used to soften them? The latter, because PVC is rigid and stable without them. |
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Bedrock of the Community
United States
19931 Posts |
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The deal with PVC is that when it's being squeezed, parts of the clorine seeps out and reacts with hydrogen to form hydrochloric acid, You cannot "squeeze chlorine" out of PVC. It's covalently bound! PVC degrades and releases chlorine/hydrochloric acid. It's a degradation process, not a physical process. |
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Pillar of the Community
Sweden
1078 Posts |
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You cannot "squeeze chlorine" out of PVC. It's covalently bound!
PVC degrades and releases chlorine/hydrochloric acid. It's a degradation process, not a physical process. Cheers for that! Love being corrected by knowledgeable people  |
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Valued Member
United States
64 Posts |
Store them in paper rolls. Least expensive and takes up minimal space. No plastic to melt on the coins when in a fire.
Even better just put them in a sandwich bag. You can just scoop or pour them out when you want to look at them!
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Moderator
Australia
16806 Posts |
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The deal with PVC is that when it's being squeezed, parts of the clorine seeps out and reacts with hydrogen to form hydrochloric acid...
You cannot "squeeze chlorine" out of PVC. It's covalently bound!
PVC degrades and releases chlorine/hydrochloric acid. It's a degradation process, not a physical process.The "squeezing" story presumably comes from solvent transfer. When two pieces of plastic are pressed into contact with each other - such as, a coin in a 2x2, inside an album page, inside a thick heavy coin album that's on the bottom of a stack of coin albums - any plasticizers present can migrate between the two pieces of plastic. Most of you have probably had the experience of a 2x2 that gets "stuck" inside a coin album, and when you eventually prise it out, the 2x2 is noticeably "sticky"? That's what's happened, some plasticizer from the album page has seeped into the 2x2 film. It's usually harmless, with the only "damage" being cosmetic damage to the 2x2. But if the album page is PVC (or the plasticizer is otherwise acidic), then the acidic plasticizer can migrate into the film of the 2x2. Whether it makes it all the way through the film and onto your coin, depends on two things: the temperature and on how long the two pieces of plastic remain in contact. Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis
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Pillar of the Community
 Australia
1364 Posts |
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Pillar of the Community
United States
1801 Posts |
I have been storing the bulk of my coins for 20+ years in polyethylene bags placed inside of paper 2x2s and stored in standard 2x2 storage boxes. I throw in a desiccant bag and they are set to go. Never had a problem with any degradation of the coins. The polyethylene bags are cheap, about $1.50 for 100 and I buy the 2x2 paper envelopes in bulk from my local coin store, also cheap. Just do not try to fit too many coins in the box, you do not want undue pressure from the coins pressing against each other.
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Pillar of the Community
Australia
1364 Posts |
Ok, so after reading all this I'm starting to worry now that my 'main' coins aren't being stored safely!
I have them in archival safe 2 x 2's, stored in archival safe 20 pocket pages but the binders that they are stored in are most likely not archival safe ... I use two differnet brands of binders and neither have responded when queried, so I guess not!
Do I have something to worry about regarding storage in the long term?
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Moderator
United States
187702 Posts |
I would not worry if you keep them in a stable environment (low humidity and constant temperature). High humidity with large temperature swings or really high temperatures will speed up the breakdown of materials. I have been suspicious of the 12-pocket vinyl pages made by Dansco, but I have not any any problems with them or the coins within over the last 25 years. Seems like your coins have been fine for the last 40 years.  |
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New Member
United States
49 Posts |
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if you want an easy cheap way to store bulk coins use zip lock freezer bags, include in the bag a pouch of desiccant to help keep any humidity off your coins. these are pvc free Thanks for this, I hadn't even thought of using desiccant pouches in my bags. This is a good idea. |
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Replies: 13 / Views: 5,082 |
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Posted 05/08/2017 11:12 am
