Are slabs air tight?
cinque1543
Posts: 242 ✭✭✭
Are PCGS slabs (and those from other grading firms) air tight?
0
cinque1543
Posts: 242 ✭✭✭
Comments
No.
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
Nope
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https://forums.collectors.com/discussion/comment/13954854/#Comment_13954854
When the barometric pressure increases, air will enter the slab and when the barometric pressure drops, air will exit the slab. Over a period of time, there will be an exchange of air inside the slab with the outside air which is why it's important to store your coins in a low humidity environment with a relatively constant temperature. In other words, don't store your slabs in the basement, attic, or your garage.
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
Never. There was a single generation of PCGS slabs that were WATER-TIGHT, but those seem to have disappeared.
ANA 50 year/Life Member (now "Emeritus")
What generation was that, just out of curiosity?
Evidently not, when I bought these two about 24 years ago they were fully white. I like the toning so I don't mind it at all.
Thank you all. I've noticed that some (a minority of) dealers put their slabbed coins in little envelopes. For long term storage in a bank safety deposit box, do you think these provide any level of additional protection to the coin?
The sleeves are usually too prevent scuffing of the slab, not air. It will slow down the air exchange, but that is not the main point.
All comments reflect the opinion of the author, evn when irrefutably accurate.
So we know they are not air tight, which means there is air inside, which means moisture can be present or generated, which probably isn't good for coins..... Especially with drastic or dramatic temperature swings, like @PerryHall mentioned with basements, attics, or your garages.
I'm sure it's been mentioned or discussed here at some point but vacuum sealed slabs would probably be best. Which would mean more cost to the grading services and past on to us.
I wonder if something like this would work.......minus the meat! 🤣
Disclaimer: I'm not a dealer, trader, grader, investor or professional numismatist. I'm just a hobbyist. (To protect me but mostly you! 🤣 )
You can buy and use small polyethylene bags with a zip-lock closure which are somewhat airtight for storage of individual slabs that have the added benefit of protecting the slab from scuffing.
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
Vacuum sealed hard plastic would possibly crack under thermal stress or me incredibly expensive.
Air exchange works both ways. If you seal the slab with any moisture or contaminants inside(air tight not vacuum), you increase the exposure of the coin.
All comments reflect the opinion of the author, evn when irrefutably accurate.
Intercept slab boxes, then put the whole box in a ziplock baggie, then put a desiccant cartridge in the baggie on top of the box. Squeeze most of the air out of the baggie and zip shut. Then put the whole thing in your safety deposit box. Change out the desiccant cartridge about once a year.
Mr_Spud
As far as I know no. Consequently the coins face exposure to the atmosphere, heat, humidity, etc. For effective RCI they need to be stored in a safe from the elements environment and quick turnover executed for best investment return. Otherwise one faces higher risk of them going bad in the holder.
Its really tough to prevent coins from toning.
You'd really need to stay on top of it. I have a fire rated safe. It makes me wonder if that alone makes the safe airtight.
I dont mind some coins toning but I also have a few Morgans I would prefer they stay white.
I believe this coined toned in the holder.
I have been tempted to crack it out for years and dip it. I believe its DMPL and would look better either way white.
Every time I get serious I back off. I'd like to dip it and resubmit.
This is one of my favorites. I post it probably to much but it is a coin forum. Nobody else I know cares.
Student of numismatics and collector of Morgan dollars
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The old SEGS slabs are probably as close to airtight as you are going to get. I have a 1962 Franklin Half that is blast white from an original roll that was slabbed in December 2001. In the twenty-four plus years since it has not toned at all.
It's possible that some slabs could be sealed all the way around.
I know it is just a myth that slabs are airtight. Nice coin @Morgan13
@Morgan13 be careful with fireproof safes. Many are designed to protect documents from fire damage by having a
layer of moisture retaining material that releases the moisture if the temperature rises in a fire. The released moisture is what protects the documents. But this moisture retaining material at room temperature makes the air inside the safe equilibrate to a humidity more than high enough to promote not just toning, but actual corrosion. I had a friend who bought one of those safes, he filled it full of proof sets, mint sets, etc. and they all grew bad spots.
He gave me this Kennedy to play around with. For fun I soaked it in a weak solution of phosphoric acid with a tiny amount of EDTA added. It made the black spots turn much lighter, but that’s about it. So picture this coin with all those spots being much darker and that’s what happened to his coins. They all looked like that and mold spots grew on the mint packaging.
Mr_Spud