ok here is the situation,I am trying to restore my grandfathers 78 burb. I just noticed that there are rust holes in the roof that go all the way through. I have never restored a vehical and could use some advice on the best way to fix the problem. unfortunatly at this time money is a concern. The lagest hole is about the size of a 2 litter bottle(the bottom). I am fairly good with fiberglass and have worked with bondo a little in the past, I also have a small mig welder. Any help would be great?