http://www.zerohedge.com/news/2012-...ten-filled-gold-bars-are-discovered-manhattan Government intervention? This could get big. Anything to put people off buying real stores of wealth. FIAT money rules ok?
About $150 off eBay. Stupidly simple to use. A lot of people seem to get confused though between ultrasonic and ultrasound - they are two different tests. GoldMoney have a video showing ultrasound tests on 400oz bars - the device I used is ultrasonic. Basically they are looking at a sonographic image of the interior of the bar - I'm using it to measure the expected thickness against a known thickness of the physical item, and an expected velocity of sound. The ultrasound test will show an image of a cavity or inclusion - the ultrasonic test will give a calculated thickness in mm if the item is pure, which can be compared with the actual physical thickness using calipers. Not claiming credit for the idea - there was a video on YouTube showing silver Engelhard bars being measured using such a device. I'm not convinced they are effective on coins, it is too hard to get a good reading because of the design relief, and the accuracy tolerance of the device (scale of 0.1mm) isn't accurate enough in my opinion to be used to test coins that are 2-3mm thick.
So this would only discover "layers" as such? Not a bar made completely from the wrong metal, is that right? Would you have to do a specific gravity test to weed out a lead bar or some other bar made from something other than gold or silver?
As far as i understand it, and correct me if i am wrong, the devicve works out the thickness of the bar assumings its pure silver/ gold ect. It works on the fact t hat sound travels through metals at a certain speed. So .9999 silver sound would travel at x speed where as .925 silver and sound would travel at y speed. You plug in the number and do a test and the machine works out the distnace of your bar assuming its pure silver. As you should already know the dimensions of your bar you can check it out. I saw one bar that was sopposed to be 2 mm thick. It clearly was 20 cm thick therfore fake. but a specific gravity test followed by this test should cover most of the basics. XRF is a pretty poor test for metal bars as it only measure a few microns ( 50-100 atoms) thick.
I wonder if you could you test coins and rounds by using the ultrasonic probe against the reeded edge of the coin ? If it worked it would give a little more metal for the signal to pass through (say 50mm rather than 3mm testing against a face of the coin), improving accuracy / chance of detection, and the diameter of the coin can be easily measured. Perhaps GP might be able to shed some light as to whether this might be feasible.
How to Make Gold-plated Tungsten Alloy Bar !! http://www.tungsten-alloy.com/gold-plated-tungsten-alloy-bar.html
I don't see how this is relevant, If you read it carefully you will see they have included- ". Here we declare: Please do not use our gold-plated tungsten alloy bar and tungsten alloy golden bar for any illegal purpose. " sure, if they hadn't included that, it would be a bit suss. :| Plus, they have been in business for over twenty years!
Ultrasonic won't work through the edge of a coin - tried it the other day with a 1oz minted bar that had been removed from a certicard. Too narrow.
Notice that they also offer to manufacture gold plated tungsten coins. Naturally these are manufactured as gifts and not in any way intended to sell on eBay as the genuine article. After all everyone on eBay is 100% trustworthy - right ?
