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#21
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Numismatist on PVC
In , on 12/03/2009
at 08:23 AM, "mazorj" said: So is any PVC-based flip really "safe" for long-term storage since they all contain some amount of plasticizers? Or should we view all claims that imply permanent safety as marketing puffery? Is Mylar the gold standard? How safe are coins in Mylar? Which commercial brand flips are made from Mylar? -mazorj, now nervously eying his enflipped hoard Argh, I should have read your post (and the subsequent replies) before posting my own concerns/questions! Nick |
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#22
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Numismatist on PVC
"Mr. Jaggers" lugburzman[at]yahoo[dot]com wrote in message ... Reid Goldsborough wrote: note.boy wrote: I've had some coins in PVC holders for over 40 years without any sign of damage, perhaps it depends up the exact chemical makeup of the PVC. The PVC does appear to be of the "soft" variety but the coins are stored in a cold place, perhaps high temperatures allow the PVC to do the damage, not a problem in Scotland. Billy I've heard this from others too. Some like you have coins in soft flips for years without problems. Others experience problems, first just green goo then corrosion that eventually results from it -- PVC damage -- within a year or two. And I think you hit it on the head when saying it's probably a factor of individual differences in soft flip chemistry as well as local weather conditions (heat, humidity). Could it have anything to do with the fabric of the coins themselves? I've seen more copper coins with the green goo than coins of silver or nickel. I would think so. I forget the proper technical term, but different elements have higher or lower tendencies to react with other chemicals. Nickel is relatively durable on mechanical wear and it also has a lower tendency to react with certain other chemicals, notably oxygen. That's why it's frequently found as a coating on firearms, appliances, inexpensive jewelry, and decorative fixtures. So it's probably the most resistant of the three while sitting in a flip. Without knowing the exact indices for silver and copper, I'd estimate that they are both sluts in the world of metals and their chemical interactions. Unlike nickel and chromium and special compounds such as stainless steel, they'll promiscuously couple with many Bad Boy elements that can lead to their esthetic downfall. And I agree that while silver is far from immune, in my experience it seems that copper is the one that really has the joneses for plasticizers. Copper and silver probably are not the worst offenders among the metals but they certainly are of too easy virtue for collectors who want them to maintain their original virginal sheen. Gold, of course, lives in its own noble, snobbish, rarefied world. It will readily bind with its exotic cousin mercury and its poorer cousin, silver. But it is far more chemically resistant than most other PMs to anything likely to be found in the atmosphere or in a flip. |
#23
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Numismatist on PVC
"mazorj" wrote in message ... "Mr. Jaggers" lugburzman[at]yahoo[dot]com wrote in message ... Reid Goldsborough wrote: note.boy wrote: I've had some coins in PVC holders for over 40 years without any sign of damage, perhaps it depends up the exact chemical makeup of the PVC. The PVC does appear to be of the "soft" variety but the coins are stored in a cold place, perhaps high temperatures allow the PVC to do the damage, not a problem in Scotland. Billy I've heard this from others too. Some like you have coins in soft flips for years without problems. Others experience problems, first just green goo then corrosion that eventually results from it -- PVC damage -- within a year or two. And I think you hit it on the head when saying it's probably a factor of individual differences in soft flip chemistry as well as local weather conditions (heat, humidity). Could it have anything to do with the fabric of the coins themselves? I've seen more copper coins with the green goo than coins of silver or nickel. I would think so. I forget the proper technical term, but different elements have higher or lower tendencies to react with other chemicals. Nickel is relatively durable on mechanical wear and it also has a lower tendency to react with certain other chemicals, notably oxygen. That's why it's frequently found as a coating on firearms, appliances, inexpensive jewelry, and decorative fixtures. So it's probably the most resistant of the three while sitting in a flip. Without knowing the exact indices for silver and copper, I'd estimate that they are both sluts in the world of metals and their chemical interactions. Unlike nickel and chromium and special compounds such as stainless steel, they'll promiscuously couple with many Bad Boy elements that can lead to their esthetic downfall. And I agree that while silver is far from immune, in my experience it seems that copper is the one that really has the joneses for plasticizers. Copper and silver probably are not the worst offenders among the metals but they certainly are of too easy virtue for collectors who want them to maintain their original virginal sheen. I've noticed that circulated silver-content wartime nickels seem susceptible to that green verdigris and other crud over the years while the other dates don't. |
#24
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Numismatist on PVC
"Nick Knight" wrote in message ... In , on 12/03/2009 at 08:23 AM, "mazorj" said: So is any PVC-based flip really "safe" for long-term storage since they all contain some amount of plasticizers? Or should we view all claims that imply permanent safety as marketing puffery? Is Mylar the gold standard? How safe are coins in Mylar? Which commercial brand flips are made from Mylar? -mazorj, now nervously eying his enflipped hoard Argh, I should have read your post (and the subsequent replies) before posting my own concerns/questions! Yeah, I hate it when I do that. It's bad enough when your mouth starts running ahead of your brain. When your brain starts running ahead of your eyeballs in a newsgroup setting, that just asking for trouble. OTOH, it seems that my ISP or my news provider is running behind on propagating certain posts. I sent off one at 9:33 that still isn't showing at my end and they usually pop up just seconds after I hit the Send/Receive button on my reader. A few other posts are replies to earlier posts that aren't showing either. Bad mojo tonight on the Internet servers. You can't read ahead before posting to see if your point already has been made if those posts aren't showing. :-( |
#25
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Numismatist on PVC
"Bruce Remick" wrote in message ... "mazorj" wrote in message ... "Mr. Jaggers" lugburzman[at]yahoo[dot]com wrote in message ... Reid Goldsborough wrote: note.boy wrote: I've had some coins in PVC holders for over 40 years without any sign of damage, perhaps it depends up the exact chemical makeup of the PVC. The PVC does appear to be of the "soft" variety but the coins are stored in a cold place, perhaps high temperatures allow the PVC to do the damage, not a problem in Scotland. Billy I've heard this from others too. Some like you have coins in soft flips for years without problems. Others experience problems, first just green goo then corrosion that eventually results from it -- PVC damage -- within a year or two. And I think you hit it on the head when saying it's probably a factor of individual differences in soft flip chemistry as well as local weather conditions (heat, humidity). Could it have anything to do with the fabric of the coins themselves? I've seen more copper coins with the green goo than coins of silver or nickel. I would think so. I forget the proper technical term, but different elements have higher or lower tendencies to react with other chemicals. Nickel is relatively durable on mechanical wear and it also has a lower tendency to react with certain other chemicals, notably oxygen. That's why it's frequently found as a coating on firearms, appliances, inexpensive jewelry, and decorative fixtures. So it's probably the most resistant of the three while sitting in a flip. Without knowing the exact indices for silver and copper, I'd estimate that they are both sluts in the world of metals and their chemical interactions. Unlike nickel and chromium and special compounds such as stainless steel, they'll promiscuously couple with many Bad Boy elements that can lead to their esthetic downfall. And I agree that while silver is far from immune, in my experience it seems that copper is the one that really has the joneses for plasticizers. Copper and silver probably are not the worst offenders among the metals but they certainly are of too easy virtue for collectors who want them to maintain their original virginal sheen. I've noticed that circulated silver-content wartime nickels seem susceptible to that green verdigris and other crud over the years while the other dates don't. That was my experience too, back when I naively was using recycled el cheapos from vendors instead of buying the safe flips. (I now automatically toss all flips that come with purchases and replace them with ones that I know will be stable.) Another confirmatory data point on James' original question. Thanks. |
#26
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Numismatist on PVC
How many others have found a coin in a dealer's stock at a show that was
in a soft flip, appearing not to have sold for many years and maybe not even to have been looked at in some time, and when you pull it out it's got the green goo of PVC damage on it. You show it to the dealer, and with embarrassment he throws the coin into his briefcase or whatever behind him. Some dealers have moved away from soft flips, using the archival ones (typically low-plasticizer PVC rather than Mylar). Others use 2x2s and always have, though they have their own issues with staples, fumes from the adhesive, cardboard dust, and so on. You sometimes still see coins in paper envelopes, not an ideal storage solution either, with coins sliding around and with seeing coins a hassle. Dealers like collectors sometimes use still other storage/display options, trays and so on, also none ideal, with coins sliding around in trays and with trays taking up lots of space. I still like archival low-plasticizer PVC flips. They're safe according to all evidence, keep coins in place, let you insert paper inserts into the second pocket for attribution and background information, allow for easy viewing and fairly easy coin insertion and removal (though you need to take a modicum of care so you don't scratch the coin on the stiff edge), take up little space when placing them in coin boxes, and unlike coin cabinets can be stored safely in a safe deposit box or home safe. -- Consumer: http://rg.ancients.info/guide Connoisseur: http://rg.ancients.info/glom Counterfeit: http://rg.ancients.info/bogos |
#27
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Numismatist on PVC
Reid Goldsborough wrote:
How many others have found a coin in a dealer's stock at a show that was in a soft flip, appearing not to have sold for many years and maybe not even to have been looked at in some time, and when you pull it out it's got the green goo of PVC damage on it. You show it to the dealer, and with embarrassment he throws the coin into his briefcase or whatever behind him. Some dealers have moved away from soft flips, using the archival ones (typically low-plasticizer PVC rather than Mylar). Others use 2x2s and always have, though they have their own issues with staples, fumes from the adhesive, cardboard dust, and so on. You sometimes still see coins in paper envelopes, not an ideal storage solution either, with coins sliding around and with seeing coins a hassle. Dealers like collectors sometimes use still other storage/display options, trays and so on, also none ideal, with coins sliding around in trays and with trays taking up lots of space. I still like archival low-plasticizer PVC flips. They're safe according to all evidence, keep coins in place, let you insert paper inserts into the second pocket for attribution and background information, allow for easy viewing and fairly easy coin insertion and removal (though you need to take a modicum of care so you don't scratch the coin on the stiff edge), take up little space when placing them in coin boxes, and unlike coin cabinets can be stored safely in a safe deposit box or home safe. I've often wondered if those paper inserts might exude gases that could migrate into the coin chamber and cause damage. Come to think of it, I wonder the same thing about paper slab inserts. James |
#28
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Numismatist on PVC
"mazorj" wrote in message ... "note.boy" wrote in message ... I've had some coins in PVC holders for over 40 years without any sign of damage, perhaps it depends up the exact chemical makeup of the PVC. The PVC does appear to be of the "soft" variety but the coins are stored in a cold place, perhaps high temperatures allow the PVC to do the damage, not a problem in Scotland. Billy Yes, heat can speed up certain chemical reactions and cold can slow them down. Higher temps combined with high humidity are the enemy of easily oxidizable metal surfaces such as silver and copper. Is your area relatively dry or is it like the stereotypical dank, foggy, rainy portrayals of London? We get a lot of rain here, at this time of the year we can go for a week or two with no completely dry days. We don't get much fog and the air quality is high compared to London for example. Billy |
#29
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Numismatist on PVC
"Mr. Jaggers" lugburzman[at]yahoo[dot]com wrote in message ... Reid Goldsborough wrote: note.boy wrote: I've had some coins in PVC holders for over 40 years without any sign of damage, perhaps it depends up the exact chemical makeup of the PVC. The PVC does appear to be of the "soft" variety but the coins are stored in a cold place, perhaps high temperatures allow the PVC to do the damage, not a problem in Scotland. Billy I've heard this from others too. Some like you have coins in soft flips for years without problems. Others experience problems, first just green goo then corrosion that eventually results from it -- PVC damage -- within a year or two. And I think you hit it on the head when saying it's probably a factor of individual differences in soft flip chemistry as well as local weather conditions (heat, humidity). Could it have anything to do with the fabric of the coins themselves? I've seen more copper coins with the green goo than coins of silver or nickel. James I have coins in a wide range of age, BC to very recent, and metals, copper, bronze, silver, cupro nickel, and have not noticed any PVC problems. They are Coindex brand holders. Billy |
#30
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Numismatist on PVC
Mr. Jaggers wrote:
I've often wondered if those paper inserts might exude gases that could migrate into the coin chamber and cause damage. Come to think of it, I wonder the same thing about paper slab inserts. You can buy archival paper for this. I do. Most don't. It's all about minimizing risk. You can make yourself crazy worrying about risk you can't control. -- Consumer: http://rg.ancients.info/guide Connoisseur: http://rg.ancients.info/glom Counterfeit: http://rg.ancients.info/bogos |
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