It has been said that you can sleep well with a stash of AU or AG under your bed and I must admit that for the last 10 years my stash has never much bothered me in any way.Until recently. You all have heard of the fake bars and coins that are supposed to be in circulation and in the hands of unsuspecting owners (custodians). I have become increasingly concerned with my stash since I bought it so long ago that it would be very hard to trace who sold me which item.At least one dealer has retired,some purchases were online,some face-to-face,some from overseas and the majority have come from what are called "reputable" precious metal dealers. To put my mind at ease,and learn a thing or two along the way,I have purchased a ultrasonic thickness gauge and have finished checking. I am pleased to say that all I have checked is clear.A silent thanks must go to BullionBourse,ABC,Ed Slabbert , the Perth Mint of course and a few others. The only problem I had was with a 1 gr bar from Turkey as the face of it was too small to put the instrument on. The other problem I still have is with Krugerrand's.I know the dimension of them but am puzzled what the velocity of sound is as it goes trough them ? The composition is 91.67 % AU and 8.33 % CU but I am not sure how to calculate the speed of sound .Has anyone here got an idea where I need to look ? I would suggest that you get one of those instruments as they are quite cheap and definitely will make you sleep weller
GP has said that ultrasonic is too unreliable for coins. http://forums.silverstackers.com/message-404532.html#p404532 http://forums.silverstackers.com/message-406419.html#p406419
