I TIG welded an earth mounting tab onto the frame, then drilled and fixed some of the small inclusions around the joints in the engine and gear leg mounts. I then drilled a small hole in each tube and injected a teaspoon full of linseed oil inside to stop corrosion from the inside out. Filling the holes was always going to be hard because the weld heats up the captured air, which wants to blow the molten metal straight back at ya!