Just trying to re-gasket the top piece, where the stove pipe goes. 4 bolts, two with nuts, got them out, no problem. Other two are tapped into the cast iron. Frozen solid. Soaking it with kroil (like pb blaster). Will try again in a few days. Two questions: First, is it a bad idea to use the impact driver on them (1/4" rechargable)? Second, if I try applying heat, will a propane torch get it hot enough to make a difference?