Does anyone know of a reliable, non complicated method/tool for testing the specific gravity of coins? It would be an excellent tool in anyone's armoury for detecting fakes if I could find a way measuring it to a high degree of accuracy (preferably to at least 3 decimal places)...
By the way, does anyone use the Fisch tools? I've read some interesting things about their reliability and quality, but I'd rather have some impartial opinions from people who have used them but don't have any vested interest in flogging them..
There is no easy way to test specific gravity. You go through the process and that's it. As for the Fisch tools - yes they work.
And you have to have some finesse for it. If you are not a do-it-yourselfer, a model builder or a brain surgeon, your results will be anywhere inaccurate and imprecise to wildly wrong. Believe me: I've tried with the best equipment. It's not the tools; it's the operator.
This is an accepted device for determining SG. Since it is used to determine SG of gemstones ( usually less than 2 grams), coins are much easier. The higher the resolution of the electronic scale used, the more accuracy. If you have your own electronic scale that is capable ( see requirements), it is less than $100. http://www.mineralab.com/Scale.htm Jim
AMEN!! Profound words of wisdom and experience. "Don't do this at home" unless you are methodical and have patience, in order to realize any degree of accuracy. LOL :thumb:
Thanks for your help guys. If I'm not methodical enough now, I'll have to learn to become it. I can spot most fakes by visual handling anyway, but since I've had to confirm fakes using different methods, I thought that it cannot hurt to have as wide a range of means to detect them as possible. The Fisch tools do look like a good thing to have in the armoury, but as my boss has pointed out, they will have their limitations, so I can't rely on them 100% either...
And if you are going to try to be accurate to THREE decimal places, you will probably need a scale accurate to preferably four decimal places, and you will have to use deionized water, make adjustments for the air and water temperatures, and you will need to enclose the scale and other apparatis in a wind proof enclosure. And then perform the test at least three times, preferably five times or more. Trying to get two decimal places is a bit tough, accurate to three usually just isn't worth trying.
You will also want to perform the SG tests on the ground floor or basement level because high-rise buildings sway in the wind and that can affect your measurements because the scales are so sensitive.
