Frozen water pump bolt

Cut the head off the bolt and remove the cover, slide a larger nut over the shaft off the old bolt and weld the together close to the block, most time the heat from welding it loosens the threads at the same time.
I don't own a welder. I was thinking of heating the cover and then using a impact wrench on it. I'm pretty sure the bolts gonna snap off. Then I will have to cut through the timing cover and hopefully get it off to remove the threaded part still in the block. I just posted a wanted add for a timing cover since I don't think this ones going to make it.Its gonna be a fun day today, I can tell.