Can you tell if there is silver in a roll without opening it just by weighing it?....or is the weight difference not great enough? Just wondering if anyone has tried it. Thanks.
Correct, if you have a very precise scale and all the coins are their specified weights and not worn down from years of circulation. Otherwise 99% of the time your doing nothing more than wasting your time.
A dollar FV of uncirculated clad coins (dimes/quarters/halves) is supposed to weigh 22.68 grams. A dollar FV of uncirculated silver dimes/quarters/halves is supposed to weigh 25.00 grams. But production isn't perfect, so these weights can vary, and I still haven't found an authoritative source stating official tolerances. (The relevant U.S. Code, 31.5112, doesn't state them, although it does state some limits on alloy variance.) About.com says clad half-dollars can vary by +/- 0.454 g. That translates to a +/- 9g variance in the weight of a roll (although the odds against getting a roll with all coins at one extreme or the other are astronomical). More importantly, though, coins lose weight as they circulate, albeit slowly. A silver dime that's lost 10% of its weight to wear, bringing it down to the weight of a clad dime, would certainly be worn down to Fair or AG at best -- but I'd still hate to miss it in a roll. Catching 40% halves by weight is even harder, because their weight is closer to that of a clad half (90%: 12.5g, 40%: 11.5g, clad: 11.34g). I doubt that you could reliably distinguish all-clad rolls from rolls containing 19 clad and 1 40% just by weight -- that .16-g difference would be swamped by normal variation in the rest of the coins.
Also a silver could weigh less because of wear. Something to think about. There are some youtubers who tried out the weighing technique and found it worked 60-80% of the time, so you would be missing a good chunk of silver coins.
Also a silver could weigh less because of wear. Something to think about. There are some youtubers who tried out the weighing technique and found it worked 60-80% of the time, so you would be missing a good chunk of silver coins.