Originally posted by Kremithefrog:
it's called foam board, you get it from your local crafts store. it's cheap, takes less than 5 minutes to make a heat shield. You just have to replace it every few months as it gets weak.



It took me 30 minutes to make mine, because it's fitted all around to allow minimal leakage, so the shape is complicated... but the original foam is still in there, I've never had to replace it. I just need to tape it back into position every once in a while.