I have some rust through on my passenger side rear floor pan. (Rest of the car is good.) We're not talking one huge hole, but you could drop some loose change through a few of the larger holes. Just to be clear, I do realize... Completely replacing the floorboards is the best solution. Welding in patch panels is the next best solution. The Rust Bullet technique probably comes in third. However, I have a new (well, unopened at any rate) fiberglass kit on the shelf and and I'm curious what to expect if I grind down to the metal and build up several layers of that to patch over the holes...??? I'm not building a show car, I just want to keep kids from stepping through the floor rofl2 and kill some of the noise coming up from the dumps. Thoughts...???
its been done befor. you will want to remove all rust and nutrualize the metal so no more forms under the fiberglass.
Done that lots in the 70`s. Worked good, I would still treat metal with the bullet, por or some kinda brew.
Best way is to either weld in or pop rivit in some patches, then cover with fiberglass to seal any small holes. I welded my patches over the bad holes, leaving just enough original metal for a ledge for the new panel to sit on. Then I fiberglassed the entire floor pan. It will hold water now! Got to get my new ws and back glass gaskets in before rainy season.
Another way is use the SEM panel adhesive.. Its crash rated and its the new thing its starting to be used more and more. Some people even install quarter panels with them.. I did this at work.. Cut out all the rust took clean sheet metal cut it to size and glued it in.. Tough and welds and only took a few hours start to finish.. Then Undercoated it.. I doubt that car will ever rust again.
Done this - used aluminum and riveted it in place, fiber glass mat with a two part epoxy used to make boats. That patch lasted over 15 years and I bet is still strong and holding (If the car is still on the road).
