My '87 F-150 4x4 was sitting in this guys back yard for 4 years, and the undercarriage rust is crazy bad...thick flakes peeling off in some spots. How do I take care of this? Scrape/brush/sand it off? Or is there something I can spray under there that will take care of it? Scrape and then spray? Or what? I'd really like to help clear up this issue, but not sure how to go about it. I did try using a wire brush in a few spots but it didn't seem to help that much.

 

well you have to scrape the scale off, and maybe lightly sand, then just hit it with some por-15 (you can get it from summit or there website) they also have primers and stuff to prep the surface. that seams to be the way to go.POR15, Inc. - Stop Rust Permanently - Repair Gas & Fuel Tanks

 

I'm interested in this as well. There is a guy here locally that does professional rustproofing where he washes the truck in some sort of acid solution that neutralizes the rust then he rinses and then undercoats the whole thing and sprays all the interiors of the doors and fenders, etc. Called to get a quote for my truck and he said it would cost me $600 to get it done!! Granted, I am driving a battleship, but I think I can do a lot of work myself for that much $$.

 

Ive successfully used eastwoods rust proofing system, its about 100 bucks but you need a compressor and a spray gun. Scrape off the heavy rust, spray it down with the solution, then paint.

Ive also scraped off the rust, wire wheeled the heavy rust as best I can, cleaned it all down with brake cleen, waited to dry and painted it with some rustoleum rust reformer paint (neutralizes the rust) and then topcoated with satin black. I even did it on a not so rusty toyota while back that still had mud on it and its still fine.

 

"Ospho" is also a good substance and that's available in home depot, ace hardware, and lowes for those of you who dislike mailorder and prefer to "buy it now" in person.

It's very runny as it has the consistency of water, therefore whenever I use it I hold an aluminum pie plate under the section of frame I'm brushing it on.

Two coats to make sure I got everything, then prime and paint normally with whatever you prefer to use.

 

Has anyone ever tried rustbullet instead of por15? I don't know if it's any cheaper, but they claim it is better and they say it is UV resistant too.

Car Rust Protection, Repair, Prevention by automotive car paint

 

I personally LOVE Rust Bullet!... Goes on with a gun if you want... I used it on the bottom of my project car and a few others and it is so much nicer then POR15 for application and so far better durability. I used POR15 on a different project a few years ago and first off application is messy and that stuff stays on clothes or hands or anything it touches. 2ndly POR15 for me I had some areas flake off back down to frame. With Rust Bullet it was easy clean and the ability to spray it straight from can with a 2.0tip HVLP was great for getting in all cracks, creases, bends, etc. with an even coat.

Then I applied the Blackshell as a top coat and that stuff lays out and dries to a smooth gloss finish that is amazing!!

For my money I go Rust Bullet on every project since then....

as for scale a dead blow works wonders for getting the large scale off... just whack the frame in spots and big chunks just fall off.... USE EYE/FACE protection...

 

I spray everything with ATF tranny fluid, works great, last along time, and its cheap. Can use an old Windex bottle to apply it, holds up well to normal puddle splashing.

 

DON'T USE RUST BULLET...HAD BAD RESULTS WITH THAT.

 

This past spring I used Rustoleum black on my frame. First I removed the bed, sandblasted off the rust (the was a lot) then primed it with brush-on Rustoleum red primer. After that, I brushed on the semi-gloss black. I have to say the results were much better than expected. There is no rust returning on the frame and if needed, touch up will be easy. At first I thought that the painted needed to be sprayed on, but that's not the case. Brushing on is fine. You may want to reduce it w/maybe 10 percent acetone just so it gets in where you can't reach. Trust me, this is the way to go.
Roger

 

Hi guys thanks for the information this has been a good post. Roger, Ambitious for sure taking off the bed of the truck. Kudo's to you for doing so. I do have one question for folks though- who has done Por15, rust bullit, rustolium, etc years ago and how has it held up. I would suspect any method to hold up in the short term and am wondering long term how folks have made out. Keystonepaul

 

I spilled some rust reformer on a flaky rusty woodstove years ago and it's still there. It lives outside and we fire it up every so often because of our bbq trailertrash roots.

Most of that stuff has phosphoric acid that reacts with rust.NEEDS iron oxide to react.
If it's watery enough, it will soak into the metal, goes on like chocolate milk and dries like black glass, sealed and never to rust again.
I used it on the floors of my old triumph 20 years ago and it's still there.

Best of you can actually see what your working on and make sure it soaks in.

x2 on the drain oil trick too. We also had some stuff called rack coating, it was a grease specifically designed to coat raw steel racks that went into a steam room to cure concrete.

It was just easier for me to move to the west coast wjere nothing rusts unless you live near the ocean and then that stuff rusts from the top down.

 

A good scrape and sand off ALL the rust, I mean make sure it's shinny when your done!

Or else, what ever you spray over the left over rust, will rust through again later on....


Once nice and clean, give 'er a good heavy coat of POR15 or something else that you think is good for that.


Just don't let it go this far like I did.... now i'm needing a body/full restoration!

 

If I were you I think Id be finding me either a new truck or a new body. If your handy with body work just go to your local JY pull Front Clip, Cab and Bed fix em up nice and install.

As to OP I also have been trying to sort out the best way to do the frame I actually was thinking if I did ever get to it of getting replacement parts for everything that was bolted (rivited) to the frame just to start with fresh metal there as they are obviously thinner pieces than the frame.

 

The phosphoric rust reformer I used actually needs rust to function so clean metal would require some other treatment.

POR15 is not cheap but it will even seal rusty gas tanks and pinhole leaks