Insulating and sound deadening

[ryans69chevy]

I'm trying to come up with a safe way to insulate and deaden the sound of my cab, specifically the roof. I have the outer skin removed and found GM used a fiberous material in the center.

I've searched the site, but haven't found an answer. I'm wondering what product I can use between the panels that can withstand welding. I have to spot weld the edges all the way around as well as weld the back seam.

I've heard of lizard skin, not sure if that stuff could withstand the welding process. I'm sure any of the peel and stick products would just burn up. I might call lizard skin and see what they say. Do any of you have any ideas or first hand experience? A lot of the threads I've read are of people glueing the panel back on which I'm going the welding route.

Thanks