There were some brackets on my gas tank that were welded to the tank. The brackets held fiber heat shields that long ago gave up the fight. Rust formed at the edges of the brackets. Just got done grinding away what was left of the brackets and there are some small pinholes and one 1/4" split. Am I better off welding patches over the areas, or hitting the one split with the welder, and then smearing on some JB weld gas tank epoxy and then painting the tank. Inside the tank is getting POR15 gas tank sealer. Don't be that guy that writes smack about welding gas tanks, explosions, fuel vapor, blah blah blah.
I prefer brazing for trying to seal holes in thin sheetmetal, if you can do that.
I've welded and brazed on used gas tanks before with no issue. The only problem is gasoline stuck in the pores of the metal. Gasoline evaporates at 150F. Fill the tank with boiling water, or crank up the thermostat on your water heater and fill it from that. It'll boil out all the leftover fumes and you'll be fine.
I may have used JB weld more than a couple times. The local radiator place solders patches over holes in tanks. They told me it does not create a stress point that can crack in the metal due to lower heat. Don't know if this is true or not. The last tank they fixed lasted for years with no issues.
Old timer I knew would drain the tank and then let compressed air blast it for a while. Then he would toss a lit match in it and let it go whoosh. Told me that was better than having it go woosh in your face. Ya I never tried it.
I've done JB Weld before, then seal the inside with Eastwood gas tank sealer.
