I have a few rust holes on my 1995 Z34. I was told to use some "great stuff" spray foam to fill in the holes, then cut it down with a razor, then bondo over the foam. anyone know if this works, and if it does are there any tricks involved??? thanks

 

if ur looking to rust quicker go for it... the foam will trap moisture inside of it and it will rust from the inside out... ive seen a few time where it was done... better off leaving it

 

is this rust hole near the gas tank?

 

I've used it on my house... NEVER would I use it on my car. Do it right or don't do it at all.

 

if it was done right, you would cut out the affected area and replace it with new sheet metal by stitch welding it in, then grind it down THEN finish it off with bondo to give it a smooth look. then paint!
it sounds simple but body work takes lot of practice to get it right. i got my start when i did it on school buses for many years. it wasn't too hard with them cuz it didn't have to be "show quality" but i have a decent feel for it.

 

2nd what drewskie said, fix it completely dont try to cover it up

 

84 MC passenger side

this is what happens when u try to do stuff like that... buddy bought this and as we tore it down discover the guy filled the rockers full of foam and bondoed over it... i think u can even see some of the foam in there by the door panel

 

think of rust as a virus in the car's skin, you have to remove it all before you can be certain it is not coming back