I took a cutoff saw and cut mine off. once i had the main peice off i then concentrated drilling out the spot welds. I also used my 3" cut off saw to grind some of the spot welds down, so they were thinner, then i was able to peel back the edges. i think i had my old rusted out roof off in less than 2 hours. Welding on my new one took at least 4 hours in prep time, that included marking and punching holes around the edges where the spot welds would be. Total time to install my new AMD roof was probably 8 hrs.