I used spray foam and never had any problems. I didn't use paper though, I used gauss. I also used putty to hold the gauss in place (thus preventing it from falling out). The end result was foam on the inside and only the gauss exposed to the elements. Then I just used putty to cover it all up and then primed/painted it. I just used the foam as a cheap filler and the putty as the finisher. Mind you, this is only for large gapping holes the size of a football or bigger, for anything smaller I just used putty. Of course if you're serious about your car you should in fact weld metal....
- Mike
- Mike
