NGC question

Cladiator · January 26, 2005 11:59AM

What causes the yellow discoloration of the normally white plastic inserts in NGC slabs? I've got a few NGC coins with this issue. If it's supposed to be sealed airtite for the coins protection..........???

coinfreak499 · January 26, 2005 12:03PM

Plastic is porus (I think) so nothing is totally "airtite". PCGS slabs usually cause more milk spots than NGC and quicker. But i'm not sure how it is caused.

ER · January 26, 2005 12:03PM

You know they are not airtite.

thebeav · January 26, 2005 2:02PM

<< <i>You know they are not airtite. >>

Absolutely....Remember some of the threads about people that have stored their coins in the attic and such?

Paul

dorkkarl · January 26, 2005 10:04PM

uh, if your slabs are turning yellow, i'd hate to guess what the air in your house is doing to your lungs!

K S

Conder101 · January 27, 2005 2:34PM

No he's right, there are a small numbr of NGC slabs out there where the insert is a yellowish creme color instead of the standard white. They were the result of a bad batch of plastic inserts and I have only seen them on one variety, either NGC 5 or 6 I don't remember which at the moment. I don't know if they were yellow from the start, or if the plastic missed the addition of a UV stablizer. (Many plastics will turn yellow if they are exposed to ultraviolet light. To prevent this a very small amount of a chemical is added to the molten plastic which keeps it from changing color.) The yellow tint to the slab isn't usually noticable on an individual slab, but if you put it next to a normal slab it is quite obvious.

Cladiator · January 27, 2005 4:18PM

excellent info, thanks conder!

NGC question

Comments

Leave a Comment