Ultrasonic testing of fake silver bar

This 100 gram silver bar passed XRF testing due to a thick silver plate layer - however destructive testing revealed a cheap copper core that was not even solid. The specific gravity of this bar would have been wildly inaccurate, but a simple ultrasonic thickness test even post-cutting reveals irregularities. The different measurements taken show that the internals are either not silver, or there are air cavities, resulting in wildly different readings from the front and back of the bar. This video is not meant to discredit XRF as a valid testing technique for gold and silver, but to show how ultrasonic thickness testing is a simple, affordable secondary test for bullion bars where thick plating may exceed the testing limits of XRF.