Aluminum is hard to see when it melts (will go from shiny if cleaned right to a haze) and if you sit there too long you will burn a hole.
Can you give us more details? Or a call.
I go from no melt to gone blown away. I thought there would be instructions for setting all these dials.
I will call some day, have to order parts B4 I can do anything.
What about air leak in plasma?