I think I mentioned this before. Use irontite tapered plugs. Magniflux to see where the crack goes then drill a hole at the end of the cracks so they won't travel anymore. Then stitch it with irontite plugs overlapping each one. You have to drill the hole, tap it with a tapered tap. You dip the plug in the irontite solution. Screw it in till it snaps off. When done you can grind it down to make it look nice and then paint it. Done. I have done a few hundred of them when I was in the machine shop trade, in the shop or on the road. Very good success rate.