So just how air/water/whatever tight is a slab?

Has anyone here ever tested just how 'sealed' a coin in a PCGS or NGC slab is? I know they are 'sonically sealed' but can find no information on their web sites as to how this is done, so I have to guess based upon the term that sound waves are somehow heating the plastic and fusing the halves together?

So this makes them somewhat airtight, it would seem. One of the selling points is the protection the slab provides, yet they also state to store them in a cool dry area, just as most people would store any other coin (excluding pocket change of course).

Anyone tested a slabbed coin by submerging it in water for a few days and see what happens?

I'm just bored and curious here.

Thanks.

 

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I would guess they start out water tight, but after a while?

They definitely are not completely air tight, but it's not so much due to the seams as it is the plastic itself.

 

Several folks have done this test over the years and posted about it on different forums. They all leaked. There may have been one that didn't but I'll bet after a bit of banging around it would start.. Not good odds.

 

The seal may be pretty good, but that doesn't help the fact that ALL plastics are permeable.

 

I think sonic sealing ensures that no sounds get into the capsule to upset the coin.

 

The intent of a slab isn't to protest it from water or air. They all let both in as freely as a sieve. They protect only against grubby fingers and drops onto semi-hard surfaces only.
Guy