would spraying with anti rust product help in preventing it spreading and getting worse

 

If the rest of the pan is structurally sound, sure.

 

There are several good anti-rust products you could use. I prefer the brush on coatings, but either way.


You'll need to clean this area well to know what you have, how big of a patch you need, etc. After welding, you'll need some good primer and paint to protect that new metal, inside and out.

 

 

That might not be that bad when you actually clean up the mess and can get a good look at it. It looks as much like a leaky top let water in from the top side, which soaked into the carpet padding and sat against the inside of the floor pan, as it looks like rust from underneath. But you won't know until you clean it up so only the rust is left to inspect.

The areas where the rust will usually be worst is at the left and right sides of the floor pan where they meet the kick panels, and across the front where the floor pan meets the toe boards or cowl. Each of those places the floor overlaps the adjoining panel, then they were spot welded together and sealed up with seam sealer. The seam sealer was never intended to last for 20+ years. As it dries out it pulls away from the joint, or cracks, water will wick into the gaps and the joints rust.

The front joint will probably be under the firewall insulator. There's also a rear joint behind the trunk carpet just above the back seats. It's worth a look too. It's very common for much of the seam sealer throughout the entire car to be expired. On my current 91 Firebird project, I stripped all the sealer from the entire car, inside and out. Most of it fell off in chunks, what stayed stuck usually had rust and/or dirt between the old sealer and the steel.

Vacuum up all the chunks and dirt, follow up with a rag and glass cleaner, or soapy water. Get all the dirt and rusty stains out of the way, and you'll be able to see actual rust. Depending on if it's just on the surface of the steel, or pitted, or rusted to the point you can break through the spot with an awl or a screwdriver, you can probably get away with scrubbing with a wire brush, or sanding away the oxidation, and then painting the remaining solid steel. Anyplace you can poke a hole, you'll want to cut away anything rusty. Once you have cut back far enough to find clean steel, you can weld in new steel. Just be prepared, a small hole can be surrounded by a much larger rust spot that's hidden under paint. A hole the size of a golf ball can be a hole the size of a NERF soft ball by the time you cut away the rust.

 

 

Since the floors aren't really seen by anyone, I wouldn't worry about sanding anything. The wire brush should be all the abrasion you need for paint and\or rust encapsulation goop to grab on to.

 

Check out POR-15, the company's mesh and filler. I've used it to great effect (more than a decade, perhaps 15 years, has passed and there's still no vestige of rust). Highly recommended.

JamesC

 

 

Yes.

JamesC

 

Can I get away with self tapping sheet metal over the bad spots in place of welding it in

 

Why even do that? Just put the carpet back over it and pretend you never saw the holes.

Do it right, or don't do it at all. Half measures just waste your time, and whoever ends up going back in to do it right later will have the original issue, plus they'll have to undo your shoddy work.

 

https://www.eastwood.com/no-weld-hole-repair-kit.html

 

With all due respect, POR15, Rust Encapsulator, Rust Converter, etc are short cuts that mostly just cover up the rust. It's still there, it's just under a layer of converted rust, or it's under a thick coat of paint, etc. If you don't get it exactly right, it's going to fail anyway and the rust will come back.

The right way to do it is to mechanically abrade or cut all the rust away. It can be a wire brush, media blasting, sanding, rust/paint stripping discs. They all do the same thing, they strip away the rust until you hit good shiny metal. Once the rust is removed, the good shiny metal needs to be protected to keep it from rusting. Epoxy primer is pretty commonly recommended.

The problem with POR15 any similar solutions in a can, is that they won't stick to clean shiny metal. They need a rough surface, preferably with some rust. Hence "Paint Over Rust".

The other option is chemical rust removers. Whether it's something like Eastwood's Fast Etch, or SEM Rust Mort, or Ospho, it's an acid that chemically dissolves rust, and converts whatever isn't removed. But again, it can change the top layer and leave rust underneath, that can come back. Also the acid likely needs to be removed or neutralized before applying a finish over the area.

Another chemical solution is Evapo-Rust. It's not an acid, but needs to be applied and kept wet for a period of time. After which much of the rust will scrub off, what remains will be converted. It's good stuff, but kind of a pain for body work, to keep it wet, the part needs to be submerged, or you can soak a clean rag with Evapo-Rust and cover it with plastic wrap, and weigh it down while it works.

You can also check out Youtube for all the "Walmart" solutions. There are videos of people using chicken wire and bondo, or mesh hole patch materials and Bondo Glass, or just fiberglass and resin. Look long enough and you can probably find someone swearing by applying foil HVAC ducting tape, and covering it with... whatever...

This one is pretty typical... Dude spends hours doing a bandaid fix that ends up looking like garbage, and the rust will undoubtedly come back...


Fixes like that are just a waste of time.

 

 

The only cure for rot is to cut it out and replace the metal. It's called cancer, because it is just that.

 

 

Have you tried anything like this?

 

 

 

Do you mean the square sealer patches over the floor plugs? Because there shouldn't be any adhesive anywhere else between the carpet and the floor.




If the sealer squares are the problem, take a heat gun and warm them up, and use a putty knife to scrape away the bulk of the mess. After it cools, go back with Odorless Mineral Spirits and disposable rags, scrub and soak, eventually the stuff comes off. Just keep in mind you'll have to reseal the floor plugs when you're done.

PS - I messed with POR15 a bit in the beginning. I ended up removing most of it, because it didn't stick for sour owl ****.

 

Wire brush it to clean metal prime and paint.
Rustolem will work for something like this that will be under carpet