Hi all, I recently bought an old 10oz Perth Mint silver bar (Type F) off another stacker. However after weighing the bar at home, it's showing up to be 306g instead of the expected 311g. Is this considered normal for old hand pours such as these? Or should I be worried about it being fake? I tried using a magnet on it and it isn't attracting the magnet.
Genuine. No signed of being tempered with from photos provided. Hope this help. What type of Scale you used? Try use Certified scale ( approved ), just to double check it.
I used a normal digital kitchen scale. I suspected it might not be as accurate so I tried weighing my silver coins and it was correctly showing 31g. Am not so much worried about it being off 5g, just worried it might be a fake bar or something.
Old bars often were odd weight, hence the name, some were underweight. It's not common and QC certainly got better but it's not completely beyond the pale. Of course they're supposed to be over rather than under but 5g is within a reasonable margin of error. I don't think you'll have any trouble selling it as a 10oz bar. Interesting phenomenon to note down though, you should try and get it on an accurate scale and maybe some of our own type F's on the scale to check out.
Perth Mint bars are generally over weight by a few extras gram. FYI Type F. Haven't come across one under weight yet. Would be interesting.
Kitchen scales are hardly the precision instrument to make statements like your title reads. Scales have a "bell curve" of accuracy - that's why a certified, calibrated set of scales runs in the order of $1500-2000 or more. Your scales may be bang on accurate at 500g, but out by 5% at 1kg. You say it weighs a 1 ounce coin as 31g - well if you've got scales with no decimal place precision, that could have been weighed anywhere from 30.5001 to 31.4999, and still been displayed as 31g (the correct weight is 31.1035 to 4dp) - if your coin was bang on exact weight of 31.1035g, and the scales only read it as 30.5001, that's a 2% error - which, funnily enough on a 10oz bar that should weigh a minimum of 311.035g, is 6.22g - low and behold, 311.035 - 6.22 = 304.8g, which would round to 305g. The bar isn't underweight, your scales aren't accurate enough, and have a lack of precision. 305g is within 2% error of margin of your scales, which would still account for a 1 troy ounce coin measuring 31g.
Not all places do have excess to this equipments. ( country, small town ) Plus They are not cheap. That's why I ask for the photos. He have provides many angles which I have concluded as Genuine. There are no signed the bar have been tempered with. ( ie drilled, patched, cored) Bars does have individual security marks ( Birth marks ) especially the cast bars/ poured bars. You just need to know where to look for. That's why photos are important. This will stopped ppl using destructive test, which will totally ruined it.
