I am replacing the firewall on a tank. Removing the badly damaged one and ite replacement was simply cutting the spotwelds. make sure to bolt the tank and firewall to the cowl and lower firewall before welding it back together tor proper bolt alignment. Not a task for the timid, so go slow. I had to use a piece of copper to back some of the welds to fill on metal where the new and old spotwelds lined up. Rod