I’m working with Pt 95 at the moment and seem to be getting a heap
of air pockets forming each time I try welding or melting the
metal.The join can look perfect on the surface but on filing or
further melting there’s plenty of pin head and smaller sized
cavities.What am I doing to cause this?
Is this some sort of contamination? I’m using an LPG and oxygen
Little Torch, on a Pt crucible back, no borax or carbon or fluxes in
contact, pickled in nitric before each annealing. If its
contamination as opposed to technique, is it easy to get the metal
back to being clean again? …or does it go back to the refiner.
Thanks for any help. Colin.