When I ship raw coins, I have them in 2x2's. I've decided for that little bit of extra protection I'm going to put the 2x2's in a 2½" flip (they don't fit in a 2" flip). I know enough to avoid flips containing a plasticizer (PVC damage prevention). There appears to be two main plastics used for flips: vinyl and mylar. Is one of those plastics preferred over the other?
I prefer to use the Saf-T-Mailers that are self-sealing, corrugated cardboard. They come in two sizes and can easily insert into an ordinary envelope. I usually order in quantity to reduce the cost, and the larger size can always be cut in half when shipping a single coin. I also use these for shipping slabs, but I don't recommend using a standard envelope for them. Because of the thickness, the envelope might tear open in the USPS sorting equipment. When shipping slabs, I prefer to use the smallest USPS Priority Flat Rate box. The length of the mailer makes it a tight fit, and I don't even bother using any packing material. You can get them from JP's Corner....... http://www.jpscorner.com/Bubble_Safety_Mailers.htm#Safety Chris
Saf-T-Mailers are okay. I've got a bunch. But I prefer bubble mailers for raw coins which is why I was asking about flips. For slabs I use CD/DVD mailers. More rigid which protects the slabs from getting cracked in the mail. But you've given me something new to consider. Using Saf-T-Mailers in conjunction with my bubble mailers. Since I have both I might as well use them. I need the thickness to qualify for D/C.
By the way, PVC (polyvinyl-chloride) is vinyl. I believe polypropylene, polyethylene, polyester (mylar), and a couple others are okay for archival coin storage. Make sure any coin holders you buy state which kind of material it is, otherwise it's probably vinyl (PVC).
YES! Vinyl is the shortened layman's word for the longer Polyvinyl Chloride or PVC. If the item is vinyl it's PVC. Mylar is polyethelene terephthalate (PETE #1) very safe for coins, food storage and corrosive chemical storage as it simply doesn't break down. Polyester film used on 2X2 cardboard flips is actually mylar that has been biaxially oriented meaning it's stretched and layered over itself yet is strong, and transparent while retaining the non corrosive and gas/aroma barrier proterties of the mylar.
PVC with out plasticizers do contain over half its weight as Chlorine atoms, but these retain their structure until about 70 degrees C ( 158 degrees F.) The larger stiff PVC piping or molded boxes would be safe until this limit was approached. Many people bury PM and assorted armaments in sealed PVC pipes if the ground is above water table with little consequence. Additives can be added top PVC to increase heat resistance, but should not be needed unless your ground temperature is above 158F. And if it is, you have larger problems than storage. p.s. DO not cook with PVC containers.
I prefer to use the Saf-T-Mailers that are self-sealing, corrugated cardboard. They come in two sizes and can easily insert into an ordinary envelope. I usually order in quantity to reduce the cost, and the larger size can always be cut in half when shipping a single coin. Reply: Paper contains sulfur, that can turn coins black. Would it also be true for cardboard?
Yes it is, and cardboard usually has more of it. Think of it this way, cardboard is nothing more than thick paper, so the thicker the paper is, the more sulfur it contains. And then there's the glue in cardboard added on top of that. If you are going to ship coins, go ahead and use the soft flips. Short term, there is no risk of PVC. Soft flips also have the advantage of not having sharp edges like mylar flips do that can scratch and or hairline coins. And, the softer plastic is far less likely to cause light wear on the high points of the coins. Dealers have known this for decades which is why they ship coins in soft flips.
