Seriously!!!!!!!!!!!After all that it was the gas lol. Just glad now I know what it is. Thanks everyone for the help and info
Or could this be a factor, Aluminium is much more reactive than steel or even stainless, what you get away with on steel will be vastly different to allyThe crappy push fit connector on the reg was leaking.
The crappy push fit reg is on the hobby bottle I used to test the new gas. On Dc the welds just where a little darker than usual, but the arc etc was perfect.
Delighted it's working