Are these slabs OK to prevent PVC?
PillarDollarCollector
Posts: 4,662 ✭✭✭✭✭
Just curious for coins I own that are raw.
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
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What type of coin holders are not OK?
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
How about these?
https://www.ebay.ca/itm/250-A-S-E-2x2-Tetra-Snaplock-Coin-Holders-25-per-pack-10-Boxes-58728/222168041075?ssPageName=STRK:MEBIDX:IT&_trksid=p2060353.m1438.l2649
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
I'm not familiar with BCW but the main part that comes in contact with the coin is a foam insert.
the terta is ok.
guardhouse is ok
lighthouse is ok
coin world is ok
Do they make slabs like BCW?
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
guardhouse makes the tetra ones.
lighthouse makes slabs
coin world is a brand of slabs, too.
If they smell like a shower curtain and/or they’re very pliable, they are NOT OK. Rigid slabs are almost always OK. It’s the plasticizers that are added to soften some plastics that degrades over time and form PVC.
Your post implies that PVC is the result of plastic degradation over time.
I always thought that PVC (polyvinyl chloride) was a component in the 'bad' holders from the start.
Any polymer people here that can clarify?
Here’s an article that explains it without getting too technical.
https://www.ngccoin.com/news/article/1445/coin-holders-contain-PVC/
Excellent article.
Thanks for taking the time to post the link, and for the education.
Witch ones would you suggest in that case? If you have a link on ebay would be great then I will be able to buy some.
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
I just buy mine from the PCGS website. I’m sure there are equivalent, cheaper flips, but these work for me.
PVC is the material itself, not a contaminant. As others have mentioned, PVC in the hobby is usually recognizable as a pliable polymer. Hard plastics holders are generally not PVC as it isn't clear enough (I think) for that purpose. They do make industrial pipes out of hard plastic PVC, for example, but they aren't completely clear. You can see it in the flips also as the mylar flips are much clearer than the PVC flips.
The general theory is that the damage comes from hydrochloric acid (the "C" in PVC is for chloride) which is a byproduct of the degradation of the material. The stickiness you sometimes feel is monomer and plasticizer residue which is acetone soluble and easily removed. The HCl etching is irreversible.
Edited to be more expansive.
So am I safe with the BCW slabs then? I will also look into the ones on the PCGS website.
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
pcgs is selling saflips, a/k/a flips, not slabs.
OK no am all confused what are the best ones to buy and links please.
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
I would go with the Coin World "slabs." I've been using them for a long time with no problems. They will be more expensive than the ones you show but they are quality holders.
Where can I buy those? And thanks.
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!
Soooooo, I'm no chemist, but I took enough chemistry, organic chemistry, and biochemistry through my engineering and medical degrees to choke a horse. That doesn't mean I remember much of it, but here's my understanding.....
What we call PVC flips are (obviously) manufactured primarily out of PVC. By itself, PVC actually isn't very pliable. Pure PVC is very brittle and inflexible. Plasticizers are added to improve flexibility and durability. Over time, plasticizers tend to migrate out of the host materials. For PVC, esters of polycarboxylic acids (among many others) are often used as the plasticizer agent. I'm a little fuzzy on the chemistry here, but my guess is that what we call "PVC damage" to the surface of the coin is actually damage from the plasticizers and their degradation compounds (probably acids). The plastics in the more rigid types of flips don't need the plasticizer agents, but they're also a bit more unforgiving when it comes to flexing and bending.
Right here-https://www.amosadvantage.com/Store/Category/Coins/Holders/Certified-Slabs
They also have the Lighthouse NGC style slabs.
Yes, PVC itself is a brittle, hard polymer without the plasticizer. It is used industrially but I don't think it is clear enough to be used for hard plastic coin cases. The "short course" on archival holders usually focuses on "flexible flips" as PVC.
I think the sticky feeling of some coins is due to plasticizer residue which itself is easily removable with acetone. The coin damage is usually ascribed to HCl etching at a later time.
https://www.ngccoin.com/news/article/1445/coin-holders-contain-PVC/
@jmlanzaf is correct... the sticky residue is called PVC (PolyVinylChloride) because it is that component in products (flips for example) that degrades, and the active Chloride etches the metal surface. The residue can be removed - and must be or damage will continue - but the resulting surface damage is permanent. Cheers, RickO
Thanks guys!!
Collecting interests: Mexico & Peru early milled 1 reales + 1796-1891 US dimes
Sports: NHL & NFL
Thank you Lord for another beautiful day!!!