Phat! You've got it!

I'll use some layers of woven fiberglass repair cloth stapled together and painted W/ engine paint (to keep it from fraying)and sandwiched between the pan and the 1/8" plywood. I'll cut the fibeglass layers smaller than the plywood so no fiberglass sticks out around the edge. That will be very heat resistant.

HA! It ain't rocket surgery after all! Phat, you're a durn sight smarter than you look in thet thar avatar.