i've been looking into buying an ultrasonic thickness gauge. They range from $103 to on ebay to $1300. some that vary $600 in price look like the same unit from different sellers. It looks like the gold stackers video is using one of the 2 products below. http://forums.silverstackers.com/message-404405.html $800 AUD http://www.ebay.com.au/itm/Ultrason...uring_Tools_Levels&hash=item4d0cd58b06&_uhb=1 $200 AUD http://www.ebay.com.au/itm/TM8812-D...6629?pt=AU_Gadgets&hash=item2ecd6bc0e5&_uhb=1 Has anyone compared the different products on ebay? lots more brands etc here. http://www.ebay.com.au/sch/i.html?_...uge&_nkwusc=ultrasonic+thickness+guage&_rdc=1
You can use ultrasonic on bars but would need XRF if it's coins you want to test. It's the TM8812 he uses http://forums.silverstackers.com/message-331967.html#p331967. If it's good enough for GP you should be alright with it.
Might sound a daft question but what would you want/actually use a ultrasonic thickness gauge for? Is it just for measuring the thickness of things or does it do more than that ?
Depends on what you want to measure. These seem to be used to measure thickness only where it would be difficult to measure conventionally e.g. a pipe, large vessel like a storage tank etc. You are not going to get an internal image showing rods of tungsten inside gold bars or the layers in gold plated brass, nickel plated copper or silver plated steel coins for example. I assume your interest is to authenticate coins or bars but I cannot see this tool being any use whatsover for these purposes.
Photonaware, watch the videos previously posted for a demonstration of how it works. You need to enter into the device the velocity of sound for the expected material, e.g. with gold, 3240m/s. Then you can use that to measure the EXPECTED thickness of a gold bar, and compare it against the OBSERVED thickness, measured using micrometers. Should the bar contain say tungsten which has a velocity of sound of 5175ms/, the device will deliver a measurement much thinner than the actual, showing that the material conducts sound much faster than pure gold alone, implying that there may be irregularities. Then it's hacksaw time. Say it was a silver-plated lead bar, which has a specific gravity close but not the same as silver, the velocity of sound in lead is only about 1/3rd that of silver - so using the device on a 10mm thick silver plated lead bar would give a reading of something like 30mm, showing there's obviously something wrong with the bar. Works great on gold and silver bars in the 5oz-5kg size range. Useless on coins. Cheap ones work well. It's used as an indicative test, not for scientific measurement, so a cheap model is fine, they have enough precision for the required purpose.
Thanks Goldpelican. I never checked sound velocities against similar density materials. Sounds as if this could be a useful tool after all for bars at least where I guess the chances for fakes are higher. It would be interesting if a fellow stacker shared experience using one of these testers. I was thinking more about coins when I made my contribution.
I've got one, and exactly as noted here, they're brilliant for use on large bars (1oz bars are a bit thin to measure) - think in terms of 10oz bars or better. Use on thinner products such as 1oz bars or coins - not useful. Would I buy another if I lost the one I have? Yes, but only if I was a regular buyer of 10oz or better silver or gold bars, primarily in the after market. Also, you don't need to spend megabucks on these, I paid around $140 for mine delivered, and it works beautifully.
