I have a 1975 Sears Craftsman 7000watt generator with a separate plastic tank for the 16 hp twin cylinder B & S engine. I do not think I could find a replacement tank from Sears. It has a crack on the bottom corner. I have seen video's of using a soldering iron to fix, but it seems to thin to do that and there are 3 different cracks in a 3/4" area. Any good fixes that have been tried?