Numismatist on PVC
Reid Goldsborough
to previous discussions here and touching upon the issue of truth and
misinformation in numismatics. With the first, the author of the
Collector's Edge column repeats the misinformation that soft flips cause
PVC damage because "the chemical PVC is added to make the flips more
pliable" and leaches out of the plastic onto the coins. In truth, soft
flips are made of PVC, with PVC just being another name for vinyl, which
is the plastic they're made of. PVC (polyvinyl chloride) on its own is
rigid and needs plasticizers (typically, phthalate esters) to make it
soft and pliable. It's the plasticizers that cause PVC damage. The
author also incorrectly states that hard flips don't contain PVC. Some
hard flips in fact are also made of PVC but have less plasticizer in
them and are marketed as "safety flips," safer for coins than soft
flips. Other hard flips are made of a different plastic, polyester,
frequently referred to by its brand name Mylar. All this has been
discussed here, on the Web, and in the Numismatist and other
publications many times, yet the misinformation continues, not only by
some numismatic writers but by some coin supply dealers.
--
Consumer: http://rg.ancients.info/guide
Connoisseur: http://rg.ancients.info/glom
Counterfeit: http://rg.ancients.info/bogos
mazorj
"Reid Goldsborough" <reidgol...@yahoo.com> wrote in message
news:3b3g2u....@news.alt.net...
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
Mr. Jaggers
I have uncirculated coins that have been in Kointainer Saflips for thirty
years without showing any signs of deterioration. But yes, all claims of
permanent safety are puffery. It's that pesky entropy thing that'll getcha
in the end.
James the Biologically Evolved
stampco
------------------------------------------------------------------------------
M.Meghrig & Sons in Los Angeles manufactures flips with reduced PVC.
They call it "Generic Archival" or as above author says "rigid
flips".
Without a minimum of PVC these holders would be unusable. In the last
18 years that Meghrig has been manufacturing these generic archival
flips has never encountered any problems of migration of softeners.
Granted... Mylar is top of the line but the cost is prohibitive.
Generic Archival of Meghrig 's flips serve the same purpose for much
lesser cost.
mazorj
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
news:hf8f0...@enews2.newsguy.com...
Okay, that's a good testimony to the Kointainer ones.
Entropy will win in the end for all things, but before the universe settles
down to an amorphous mass, a few other things will happen, like all those
clear sheets of supercooled liquid (a.k.a. glass) puddling under my windows.
That's going to let in the elements, which can't be good for coin storage
regardless of which brand of flips you use.
I'll be happy if my specimens survive without visible damage long enough for
my children to appreciate what I've passed on to them. After that, it's
their problem!
- mazorj the Bequeather
Mr. Jaggers
It's only a matter of time until some loudmouth swings through here and goes
ad hominem on you for claiming that glass is a supercooled liquid.
Meanwhile, here's a disquisition on the topic:
http://math.ucr.edu/home/baez/physics/General/Glass/glass.html
James the Vitreous
Reid Goldsborough
> So is any PVC-based flip really "safe" for long-term storage since they
> all contain some amount of plasticizers?
PVC safety flips are distinguished by the amount of plasticizers they
contain, which is much less than regular soft PVC flips.
> Is Mylar the gold standard? How safe are coins in Mylar? Which
> commercial brand flips are made from Mylar?
I don't think anybody has seriously studied this. I believe polyester
(Mylar) safety flips are safer than low-plasticizer PVC safety flips.
But I believe the difference is small, perhaps insignificant. Again, I
don't think there's any evidence to back this up, just anecdotal
stories. My own practice is to put the few proof coins I have in
polyester flips (Kointain Saflips) and most of the rest in International
Plastics' low-plasticizer safety flips, sold by among others Jake's
Marketplace and FORVM Ancient Coins. I believe the low-plasticizer
safety flips might be problematic in high-heat, high-humidity
environments, but otherwise they're fine. I've read or heard nothing,
anecdotally, to the contrary. Others like them, I know, but I personally
find the Kointain Saflips ugly, with their striations, sharp corners,
and flimsiness, making the coin/flip package less attractive to look at
than coins in the low-plasticizer safety flips. Again, just my view for
my coins.
Mr. Jaggers
I just checked an unopened pack of Saflips. It says they are made of
Polyethylene Terephthalate (a/k/a polyester) and that they are "inert and
flexible" and "Contain no PVC or Oil."
Yes, they do have the striations and sharp corners, and some of my older
ones crack if I open them far enough to take the coins out. I don't know if
the formula has changed or not in 30 years, but if not, I suppose they will
all crack one day. At something like 15c a throw retail, that can get
expensive.
James
note.boy
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
"Reid Goldsborough" <reidgol...@yahoo.com> wrote in message
news:3b3g2u....@news.alt.net...
mazorj
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
> mazorj wrote:
...
>> Entropy will win in the end for all things, but before the universe
>> settles down to an amorphous mass, a few other things will happen,
>> like all those clear sheets of supercooled liquid (a.k.a. glass)
>> puddling under my windows. That's going to let in the elements, which
>> can't be good for coin storage regardless of which brand of flips you
>> use.
>>
>> I'll be happy if my specimens survive without visible damage long
>> enough for my children to appreciate what I've passed on to them. After
>> that, it's their problem!
>
> It's only a matter of time until some loudmouth swings through here and
> goes ad hominem on you for claiming that glass is a supercooled liquid.
>
> Meanwhile, here's a disquisition on the topic:
>
> http://math.ucr.edu/home/baez/physics/General/Glass/glass.html
>
> James the Vitreous
Wow. Thanks for the great link. It nicely explained the science, debunked
the "flowing glass" myth, discouraged the misnomer "supercooled liquid," but
rightfully demurred on the unanswerable question of whether glass is a
liquid or a solid. It was far superior to most of the links to
documentation that pass for "proof" on Usenet.
Shoulda checked first - I got the "supercooled liquid" explanation in high
school physics class in the 1960s... taught by a priest. Which probably
explains his reference to church glass as proof of the phenomenon. In
fairness, he was pretty sharp on science (he taught our chemistry class as
well) and our knowledge of sub-macroscopic properties of materials was less
sophisticated in the 1960s than it is today, so this presumably was a common
misperception even in scientific and engineering circles at the time.
I once participated in a project that involved the effects of "super-cooled
drizzle drops". From which my main take-away was that "Super-Cool Drizzle
Drops" would be a great name for a candy. :-D
Mr. Jaggers
I had the same story told to me in a secular school setting, and in more
than one class, so I hold nothing against anyone who holds fast to the
"supercooled liquid" claim. As we have both now seen, the article itself
was not as definitive as it might have been. As one who has had
considerable experience cutting, drilling, and shaping pieces of glass, I
can attest to its very quirky nature. But I have just a wee bit of trouble
explaining how I got all those cuts from handling a "liquid." 8>)
James the Lacerated
mazorj
>
>> So is any PVC-based flip really "safe" for long-term storage since they
>> all contain some amount of plasticizers?
>
> PVC safety flips are distinguished by the amount of plasticizers they
> contain, which is much less than regular soft PVC flips.
Right, but are the low-plasticizer flips truly "safe"? (I know, the correct
answer to that is "define 'safe' for me" so I would arbitrarily set a limit
of, say, 30 years for long-term possession by the average collector, where
no damage can be noted under moderate magnification.)
>> Is Mylar the gold standard? How safe are coins in Mylar? Which
>> commercial brand flips are made from Mylar?
>
> I don't think anybody has seriously studied this. I believe polyester
> (Mylar) safety flips are safer than low-plasticizer PVC safety flips. But
> I believe the difference is small, perhaps insignificant. Again, I don't
> think there's any evidence to back this up, just anecdotal stories. My own
> practice is to put the few proof coins I have in polyester flips (Kointain
> Saflips) and most of the rest in International Plastics' low-plasticizer
> safety flips, sold by among others Jake's Marketplace and FORVM Ancient
> Coins. I believe the low-plasticizer safety flips might be problematic in
> high-heat, high-humidity environments, but otherwise they're fine. I've
> read or heard nothing, anecdotally, to the contrary. Others like them, I
> know, but I personally find the Kointain Saflips ugly, with their
> striations, sharp corners, and flimsiness, making the coin/flip package
> less attractive to look at than coins in the low-plasticizer safety flips.
> Again, just my view for my coins.
All of my nicest loose specimens get coddled by being encapsulated in
Kointains or similar two-piece holders, so I don't need no (literally)
steenkin' plasticizer-leaching flips for them.
The issue of softening PVC does raise the question of at what point does a
flip or other pliable holder become so rigid that its surface might scratch
a coin surface? We already know of the hazards presented by the sharp
leading edges of the sliding clear plastic covers in upscale albums. Could
a low-plasticizer PVC or Mylar flip abrade high-relief points on frequently
handled coins that are only protected by the flips? As with the other
questions raised here, empirical testing would be the only way to answer
that.
Mr. Jaggers
It's not so much the stiffness of flips or the sharp leading edges of
acetate or mylar album slides that scratches coins as it is tiny grains of
grit or other debris that gets deposited on the surface of the coin and then
scraped across it.
James the Experienced
mazorj
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
...
> I had the same story told to me in a secular school setting, and in more
> than one class, so I hold nothing against anyone who holds fast to the
> "supercooled liquid" claim. As we have both now seen, the article itself
> was not as definitive as it might have been.
And I would say "with good reason" because some of our current terminology
and semantics have not kept pace with science.
The deeper we peer into the microscopic world, the more we are disabused of
many of our overly simple macroscopic explanations and either/or
categorizations. Is a photon a particle or a wave? Is a virus a plant or
animal? Does it deserve a place in the Linnean classification, and if so,
where and as what? Is it even alive? What about Schroedinger's cat? Alive
or dead? C'mon, now, it's a simple question! Yes or no! (Okay, please, no
carping from the peanut gallery. I know there are answers to my rhetorical
questions. I'm just making a point, not trying to start a flame war here.)
IMO the author was authoritative where he could be, and he refrained from
going too far out on limbs that can't or shouldn't support overly freighted
opinions. As he noted, "liquid versus solid" in this case is largely a
matter of semantics because our knowledge of the states of matter has made
such either/or distinctions ambiguous at best and not really useful to
scientific inquiry into the properties of glass.
> As one who has had considerable experience cutting, drilling, and shaping
> pieces of glass, I can attest to its very quirky nature. But I have just
> a wee bit of trouble explaining how I got all those cuts from handling a
> "liquid." 8>)
>
> James the Lacerated
I still remember my astonishment the first time I got a paper cut in grade
school. What? Paper is thin and flimsy! It can't even stand up by itself!
I can tear it and crumple it with my hands! It wins over a rock but it
loses to scissors, which I'm not supposed to run with because they have real
cutting edges! Should I not run with paper too? What the hell is going on
here?
So is paper a knife or is it dried cellulose pulp derived from wood, rags,
and certain grasses?
- mazorj the Semanticist
Mr. Jaggers
So many questions, so little time. These questions, and many more,
represent evidence that claims of absolute truth are unsupported. Excuse
me, I need to don my asbestos suit now.
James the Relativist
'Lay on, Flamers!'
mazorj
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
> mazorj wrote:
...
>> The issue of softening PVC does raise the question of at what point
>> does a flip or other pliable holder become so rigid that its surface
>> might scratch a coin surface? We already know of the hazards
>> presented by the sharp leading edges of the sliding clear plastic
>> covers in upscale albums. Could a low-plasticizer PVC or Mylar flip
>> abrade high-relief points on frequently handled coins that are only
>> protected by the flips? As with the other questions raised here,
>> empirical testing would be the only way to answer that.
>
> It's not so much the stiffness of flips or the sharp leading edges of
> acetate or mylar album slides that scratches coins as it is tiny grains of
> grit or other debris that gets deposited on the surface of the coin and
> then scraped across it.
> James the Experienced
Absolutely true. But I'm reasonably confident that in an encounter between
a high relief point such as a nose or ear or whatever, and the leading edge
or inside surface of an album slide, both will suffer. The damage to the
coin may only show under extreme magnification, but it will be there. I'm
meticulous about seating coins in such albums so that both the obverse and
reverse sides have adequate clearance from the slide. Your point, well
taken, suggests that a blast of canned air and/or a gentle vacuuming with a
hand-held minivac (being careful not to touch the coin) would be in order
before sliding the cover shut.
Ditto for storing coins in flips. Grit and contaminants from the atmosphere
surrounding the flip can do more damage than plasticizers or abrasion from
contact with the flip. I only raised the issue as a mostly but not entirely
theoretical concern.
Hmmm... Methinks the ideal storage solution is embedding your coin in a
solid block of pure silica glass. It's well protected, easily handled,
there's no movement within the container to cause dings or abrasion, no dirt
or chemical contaminants can get at it, and you can view it from every
angle. All you need is Windex to clean off the smudges.
There is the slight matter of what will happen to the coin when you immerse
it in a pool of liquid silica at 1,300 degrees Celsius, but that's a mere
engineering detail. Once I get that part perfected, watch for the
introduction of the amazing new "Glaztainer" for coins, brought to you by
mazorjco. It will give new meaning to the numismatic term "slabbing".
- mazorj the Entrepreneur
mazorj
"note.boy" <note...@naespamntlworld.com> wrote in message
news:BBURm.6526$6p6....@newsfe05.ams2...
> 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?
Reid Goldsborough
> 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).
Mr. Jaggers
> 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
Nick Knight
12/03/2009
>M.Meghrig & Sons in Los Angeles manufactures flips with reduced PVC. They
>call it "Generic Archival" or as above author says "rigid flips".
>Without a minimum of PVC these holders would be unusable. In the last 18
>years that Meghrig has been manufacturing these generic archival flips has
>never encountered any problems of migration of softeners.
Interesting. While Reid has mentioned this topic has been discussed over
and over again, I'm still not sure I've done the right thing. Based on what
I had read previously, I purchased some flips (and I swear there were called
"Safety Flips" or some-such), and now I'm not sure of their safety.
I've owned quite a few coins for more than 18 years, and I'd like to think I
might have another 40+ years to go (I'm being very optimistic!) So, what
should I be looking to buy that will be safe, or at least safer, than what I
currently have on my shelf (and around many coins)?
Nick
Nick Knight
>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
mazorj
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
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.
Bruce Remick
"mazorj" <maz...@verizon.net> wrote in message
news:hfa0gr$kme$1...@news.eternal-september.org...
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.
mazorj
"Nick Knight" <bhnc...@mr2ice.com> wrote in message
news:4b1877de$10$avpx$mr2...@news.east.cox.net...
Yeah, I hate it when I do that. It's bad enough when your mouth starts
running ahead of your brain. When your brain starts running ahead of your
eyeballs in a newsgroup setting, that just asking for trouble.
OTOH, it seems that my ISP or my news provider is running behind on
propagating certain posts. I sent off one at 9:33 that still isn't showing
at my end and they usually pop up just seconds after I hit the Send/Receive
button on my reader. A few other posts are replies to earlier posts that
aren't showing either. Bad mojo tonight on the Internet servers. You can't
read ahead before posting to see if your point already has been made if
those posts aren't showing. :-(
mazorj
"Bruce Remick" <rem...@cox.net> wrote in message
news:jN%Rm.48915$ky1....@newsfe14.iad...
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.
Reid Goldsborough
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.
Mr. Jaggers
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
note.boy
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
note.boy
"Mr. Jaggers" <lugburzman[at]yahoo[dot]com> wrote in message
news:hf9m8...@enews5.newsguy.com...
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
Reid Goldsborough
> 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.
Mr. Jaggers
> 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.
The inserts in my oldest Saflips have turned sort of a bilious off-white,
but the coins appear to be unchanged.
James the Relieved