What are you welding?
I'm not sure what your welding, but the RV tanks are made from 2024 (welding not recommended for 2XXX series aluminum)..but you can make a heatshield per say for the nutplate area with some water soaked rags or paste insulation. TIG/MIG welding doesn't create as much heat as torch welding. I have seen Proseal handle some pretty good heat, but do not have factual temperatures.
8A7 / Advance NC