Someone erasing evidence? The serial number has been conveniently disfigured by the house fire... http://www.ebay.com.au/itm/Palladiu...80669539814?pt=AU_Bullion&hash=item2a10be65e6
It's a bit under spot... Would be good for someone with an XRF. Don't know any palladium refiners though.
Palladium's melting point is 1554 degrees C. From a brief google, house fires can reach 700-800 degrees. I don't have any experience with melting metal, but could this damage occur if the temps are so far below its melting point?
Do people use the serial numbers to track? Would it be worth the effort of just making it illegible instead of melting down the bar completely? The relative value of it being PAMP would be pretty much nil due to the damage, why not just melt it completely?
Because dealing with 10oz worth of molten metal at +1500 degrees is a giant pain in the @rse; but removing traceable numbers is fairly easy, and all that is required.
It's difficult to "surface melt" these metals. Palladium is a very good conductor and develops a surface tarnish when exposed to sulphur (silmilar to silver). Whenever one applies a blowtorch (like oxyacetylene) to metals like this (aluminium for instance) the heat gets sucked away to the centre of the piece and the surface crust tarnish obscures what's happening underneath. You keep pouring the heat on thinking nothings happening and then all of a sudden the whole peice falls away as a molten blob.