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I know this is going to be an odd question but... Are slabs supposed to be air tight?
mrpaseo
Posts: 4,753 ✭✭✭
You know Air/Water tight?
Ray
Ray
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<< <i>No way! >>
that
Seems like it would take very little engineeering to make them that way.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
<< <i>Remember the forum member that was caught artificially toning white silver coins that were already sealed in old rattler slabs? This would have been impossible if they were air tight. >>
You beat me to the punch
<< <i>Remember the forum member that was caught artificially toning white silver coins that were already sealed in old rattler slabs? This would have been impossible if they were air tight. >>
Was this done to prove a point (i.e. as an educational tool) or was it done with a malevolent intent? Are there any threads on this (I seem to be having problems with the search tool)?
<< <i>You know Air/Water tight?
Ray >>
To address the water tight aspects, there are some "interesting" anecdotal tales ATS if you're interested.
<< <i>there's also the strange and humorous tale of the member who reported here with a question about how to dry a slab he'd dropped in the bathtub...................looking at coins while bathing. now that's a hard core and dedicated collector.!!!!!
Who here has viewed a coin or two in the midst of a "morning constitutional."
<< <i>
<< <i>there's also the strange and humorous tale of the member who reported here with a question about how to dry a slab he'd dropped in the bathtub...................looking at coins while bathing. now that's a hard core and dedicated collector.!!!!!
Who here has viewed a coin or two in the midst of a "morning constitutional."
Exactly what I thought... If you do not have a loop on a pull string next to the throne, do not consider yourself hardcore...lol.
Ray
Plastics are by their nature, gas-permeable, and air is a form of gas.
Also, when the TPG encapsulates are introduced to wild temp/humidity swings you can count on the likely possibility of developing condensation on the inside of the plastic enclosure...................
<< <i>
<< <i>Remember the forum member that was caught artificially toning white silver coins that were already sealed in old rattler slabs? This would have been impossible if they were air tight. >>
Was this done to prove a point (i.e. as an educational tool) or was it done with a malevolent intent? Are there any threads on this (I seem to be having problems with the search tool)? >>
Those threads were poofed. I guess our hosts didn't want to give anyone any ideas.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
perhaps i'm mistaken, but this is just not correct, i believe that slabs are sonically sealed. as such, they are neither air tight nor water tight.
<< <i>In order for slabs to be air/watertight they'd need to have each half be a nearly perfect fit or they'd need a sealant of some sort. An O-ring gasket groove around the coin [but not touching it might also be a possibility. >>
If I'm not mistaken, the plastic itself allows air to pass through it.
``https://ebay.us/m/KxolR5
<< <i>
<< <i>In order for slabs to be air/watertight they'd need to have each half be a nearly perfect fit or they'd need a sealant of some sort. An O-ring gasket groove around the coin [but not touching it might also be a possibility. >>
If I'm not mistaken, the plastic itself allows air to pass through it. >>
I sorta doubt that for this kind of plastic. I think over time that moisture can migrate through polyethylene [polythene to the Brits] esp. the LDPE.
Ray
...GLASS!!!! better yet how 'bout amber? never saw any prehistoric bugs decayed in amber!...
<< <i>So is there no solution? I guess vacuum sealing them in food bags would limit the transfer of water and air to the coins but who wants to do that? Are the TPG companies not working on this? Do you think they should be?
Ray >>
one probably could just address this themselves and at least glue the seams if concerned
yeah in retro about that member here who got caught...what a hoot that was..."OOPS"
good question to be cleared up on too...
Eric
Edited to add: Certainly gas permeable, I recall the 50 ASE's that demonstrated this to non-believers ...
Let's just say that the coin did not look good at all.
Not watertight!
--Edward
He who knows he has enough is rich.
The slabs are gas permeable (apparently right through the plastic, but perhaps more so at the sonic seams; some have suggested sealing the edge seams with clear fingernail polish), but the plastic they are made of is not harmful to the coins. As mentioned above, changes in air pressure will cause air movement in and out of slabs. Some solutions to minimize the effect of air on your coins have been developed and include: Intercept shield technology, and storing the slabs in the safest environments possible. Reducing exposure to oxygen, sulfur, PVC, and moisture are probably the most important. I am not an expert on this, but have done some reading. I have at times sealed some of my slabs inside ziplock bags (food quality plastics are mandated to be free of PVC) which gives an extra layer of protection for movement of air. I have even considered buying some sealable plastic food containers to put slabs in.
There is an occasional article in Coin World by Susan Maltby on such topics that I always try to read and understand.
Probably the single best protection would be the Intercept shield materials, but they do have their costs.
Anyone else want to add to this?
edited to correct typos
Like some high humidity paper SDB's in banks? Years ago lots of folks did not believe this anymore than "cherry" wood, unknown adhesives, glue , velvet, all can tone cojns. I know you read Maltby
Eric
<< <i>condensation in a closed system?
Eric
Edited to add: Certainly gas permeable, I recall the 50 ASE's that demonstrated this to non-believers ...
If you take a glass bulb filled with normal air and seal it and then cool it down far enough, you can probably get the small amount of water inside to condense out. However this doesn't have much relevance to normal coin storage, unless you are one of those who keeps his coins in a freezer.
<< <i>There was an article in Coin World a few years back where they took several inexpensive blast white morgan dollars of low value in slabs from PCGS and NGC and subjected them to closed environments high in sulfur dioxide gas. The coins in the slabs (both TPG's) under this intense exposure did become noticeably darker in a short amount of time, a few weeks or less if I remember correctly. You certainly don't want your coins in slabs exposed to sulfur fumes like this of high concentration or lesser concentrations.
The slabs are gas permeable (apparently right through the plastic, but perhaps more so at the sonic seams; some have suggested sealing the edge seams with clear fingernail polish), but the plastic they are made of is not harmful to the coins. As mentioned above, changes in air pressure will cause air movement in and out of slabs. Some solutions to minimize the effect of air on your coins have been developed and include: Intercept shield technology, and storing the slabs in the safest environments possible. Reducing exposure to oxygen, sulfur, PVC, and moisture are probably the most important. I am not an expert on this, but have done some reading. I have at times sealed some of my slabs inside ziplock bags (food quality plastics are mandated to be free of PVC) which gives an extra layer of protection for movement of air. I have even considered buying some sealable plastic food containers to put slabs in.
There is an occasional article in Coin World by Susan Maltby on such topics that I always try to read and understand.
Probably the single best protection would be the Intercept shield materials, but they do have their costs.
Anyone else want to add to this?
edited to correct typos >>
I would think that they would have used hydrogen sulfide gas instead sulfur dioxide. Also if one was to 100% seal the slab and do the same thing, I bet it would show that gasses don't pass through the slab itself.
One solution might be to devise a 2 piece outer ring [similar to the doily and its brothers] that is 100% sealed with something like super glue.
<< <i>Yes, I think you are correct. It was hydrogen sulfide gas, but it reacts with the silver in silver coins turning them dark. Thanks for the correction. I was trying to do this from memory. You know how that can go. >>
If I remember that article, NGC slabs did a better job of protecting the coins from adverse atmospheric conditions than did the PCGS slabs.
Worry is the interest you pay on a debt you may not owe.
"Paper money eventually returns to its intrinsic value---zero."----Voltaire
"Everything you say should be true, but not everything true should be said."----Voltaire
<< <i>
<< <i>condensation in a closed system?
Eric
Edited to add: Certainly gas permeable, I recall the 50 ASE's that demonstrated this to non-believers ...
If you take a glass bulb filled with normal air and seal it and then cool it down far enough, you can probably get the small amount of water inside to condense out. However this doesn't have much relevance to normal coin storage, unless you are one of those who keeps his coins in a freezer. >>
Hi,
Anything to add? Yes, sacrificial anode!
I was just observing double paned windows I see when I walk (I do not live in a freezer) - twice a day they get condensate even with very moderate changes in termp etc. Maybe this is a bad analogy. Open systems breathe a bit to prevent this by allowing equalization? IDK. I think storage in anodized aluminum with an inert gas (nitrogen was it?) and some type of non-permeable "plastic" material. THAT would be some secureplusplus slab! Is anything worth constructing such a case for? In any event, no wood storage cases for me!
Eric
If you have had coins that have changed in the slab, it was likely caused by something that was on the coin prior to it being slabbed such as dip residue, a latent finger print or a small drop of saliva. I typically don't buy coins that are already in slabs, and every single coin gets a good soak in acetone and a rinse in distilled water before being sent in. I have no idea how the coin has been handled over the years prior to my ownership and acetone and distilled water are a good and cheap insurance policy against later degredation.
JJ
<< <i>If you keep your coins stored in a normal environment such as a desk drawer or safe then you have nothing to worry about. Most homes are air conditioned and force air heated which tends to keep the humidity low to begin with. I have had slabbed coins sitting in a desk for years with no change in appearance. If you are storing your coins in your teenaged daughter's bathroom as she takes 20 minute steaming hot showers, you might have a problem.
If you have had coins that have changed in the slab, it was likely caused by something that was on the coin prior to it being slabbed such as dip residue, a latent finger print or a small drop of saliva. I typically don't buy coins that are already in slabs, and every single coin gets a good soak in acetone and a rinse in distilled water before being sent in. I have no idea how the coin has been handled over the years prior to my ownership and acetone and distilled water are a good and cheap insurance policy against later degredation.
JJ >>
A safe? Maybe - RH? what else is in there? A ring in a jewel box with felt and glue? Lots of paper? IHK...
Eric
<< <i>
<< <i>Yes, I think you are correct. It was hydrogen sulfide gas, but it reacts with the silver in silver coins turning them dark. Thanks for the correction. I was trying to do this from memory. You know how that can go. >>
If I remember that article, NGC slabs did a better job of protecting the coins from adverse atmospheric conditions than did the PCGS slabs. >>
That might be true especially since some have an "air bubble" trapped inside that doesn't seem to dissipate. Also might be why NGC slabs "seem" to have fewer spotted ASEs in them.
<< <i>
<< <i>
<< <i>condensation in a closed system?
Eric
Edited to add: Certainly gas permeable, I recall the 50 ASE's that demonstrated this to non-believers ...
If you take a glass bulb filled with normal air and seal it and then cool it down far enough, you can probably get the small amount of water inside to condense out. However this doesn't have much relevance to normal coin storage, unless you are one of those who keeps his coins in a freezer. >>
Hi,
Anything to add? Yes, sacrificial anode!
I was just observing double paned windows I see when I walk (I do not live in a freezer) - twice a day they get condensate even with very moderate changes in termp etc. Maybe this is a bad analogy. Open systems breathe a bit to prevent this by allowing equalization? IDK. I think storage in anodized aluminum with an inert gas (nitrogen was it?) and some type of non-permeable "plastic" material. THAT would be some secureplusplus slab! Is anything worth constructing such a case for? In any event, no wood storage cases for me!
Eric >>
I expect that double paned windows aren't air tight. The trapped air is an insulator. Scopes and other optics for rifles/hunting etc. are filled with dry inert gas to prevent fogging in cold weather. I have heard of freezers being recommended to store documents and maybe coins because they offer a measure of fireproof protection and burglars often don't think to look there.
<< <i>
<< <i>
<< <i>
<< <i>condensation in a closed system?
Eric
Edited to add: Certainly gas permeable, I recall the 50 ASE's that demonstrated this to non-believers ...
If you take a glass bulb filled with normal air and seal it and then cool it down far enough, you can probably get the small amount of water inside to condense out. However this doesn't have much relevance to normal coin storage, unless you are one of those who keeps his coins in a freezer. >>
Hi,
Anything to add? Yes, sacrificial anode!
I was just observing double paned windows I see when I walk (I do not live in a freezer) - twice a day they get condensate even with very moderate changes in termp etc. Maybe this is a bad analogy. Open systems breathe a bit to prevent this by allowing equalization? IDK. I think storage in anodized aluminum with an inert gas (nitrogen was it?) and some type of non-permeable "plastic" material. THAT would be some secureplusplus slab! Is anything worth constructing such a case for? In any event, no wood storage cases for me!
Eric >>
I expect that double paned windows aren't air tight. The trapped air is an insulator. Scopes and other optics for rifles/hunting etc. are filled with dry inert gas to prevent fogging in cold weather. I have heard of freezers being recommended to store documents and maybe coins because they offer a measure of fireproof and burglars often don't think to look there. >>
Thats what I was getting at with the nitrogen or argon or whatever it was. Air. Gotcha
Eric