Body rust repair question

[Southern_Trendkill]

I have the signature Ford rust over the rear wheels that I plan to fix next week when I have time off. I already bought everything to paint it, but it turns out the rust if worse than I thought. It has little chunks breaking out of it, but I think it's still solid enough that I can use some body filler to fix it.

My question is - am I better off using Bondo, epoxy, or quiksteel to smooth out the area before I paint it? And does anyone have any special techniques for this kind of work?

 

[lil_Blue_Ford]

You have to cut out the cancer and stop the rust before you can patch it. If you just smear bondo over the rust, in a year or so it'll be bleeding right back through.

If I have to salvage a panel that has rust through, I'll cut out as much of the cancer as possible and clean the rest as best I can (wire wheels, flap disk on a grinder, naval jelly, etc). If it leaves a hole, I'll patch it with fiberglass and skim it with bondo and/or glazing putty. If it just leaves a low spot I'll bondo it. I use fiberglass reinforced bondo to build up, then a glazing putty to fill in.

Sanding is key to a good job.

I patched up a Bronco II once because I didn't have the cash for replacement panels, took a good bit of fiberglass work to do it, but it didn't look half bad when I was done. My F-150 has a half-baked rear wheel arch fix on the one side, I should get pictures of it... he got a replacement panel, put it over top of the rusted area, pop riveted it in place, bondo'd the hell out of it and squirted paint over it. And didn't get it lined up right. Of course, the rust is starting to show around the edges of the panel an the pop rivets are starting to show through teh bondo...

I'm going to do the other side right, cutting it out, flanging the panel and welding in a replacement. I can get a new panel for somethin like $25, stupid cheap as far as I'm concerned.

 

[ZMan]

like Jon said, putting bondo over rust is a temporary fix. Rust almost ALWAYS comes from the inside out, to fix it properly you'll need to cut it all out and replace it, and use a welder to do so.

Its your call though, how long do you want it to last?

 

[Southern_Trendkill]

The problem's changed a bit now...

I thought it was just minor surface rust. Then I tried to pull off the trim piece around the wheelwell so I could start sanding. A piece about the size of my fist came off with it. It's an ass-load of rust.

 

[kunar]

The problem's changed a bit now...

I thought it was just minor surface rust. Then I tried to pull off the trim piece around the wheelwell so I could start sanding. A piece about the size of my fist came off with it. It's an ass-load of rust.

it always happens that way too.... looks small but once you get into it, it all just falls apart.

 

[Zachalanche]

you're not alone. mine was just a buble in the paint. when i sanded past it I found there was no metal left and a bunch of mud packed inbetween the inner and outer fender. when I get some time and money I'll probably either weld in a patch panel or get fiberglass bed sides.

 

[modelageek]

I am a novice with body work ut couldn't you just cut out and grind off the rust paint it with por-15 and put some of those rubber fender flares over it

 

[ZMan]

I am a novice with body work ut couldn't you just cut out and grind off the rust paint it with por-15 and put some of those rubber fender flares over it

thats not body work, thats hiding, lol. and POR-15 doesn't work the way they say it does. The only real way to fix rust is to get rid of it, whether it be sandblasting, cutting it out, etc.

 

[Downey]

you need to sand back the paint and find good metal. once you find out how far the rust goes back you can order patch pannels from lmctruck or raybucks. but you will need a welder to weld them in. also if you do get patch pannes dont just stick them over the rust cut all the rust and bad shit out and weld them in nice and clean.



Bondo or any body filler should never be more than an 1/8th inch think. bondo isnt to fill holes. its designed level a surface and should be very thin

 

[85DANGERanger]

i went to school for auto body and was a auto body technician for about 2 years. so i have quiet a bit of expierence with body work. to answer your question about rust, there is no way to fix it. if you want it repaired, a new panel is going to be needed. like someone else said. rust starts from the inside out. on pickup truck beds, the reason the wheel arches rust out is because water, mud, and debris gets traped between the inner wheel well and the bedside skin. another another problem when repairing it with new panels is welding them in. its extremely hard to seal a weld when you cant get to it. and if you cant seal it, then rust will just reform on the open metal caused by the welding. most body guys know theres nothing better then factory. but theres ways to make the work last for a long time. but in your situation, id say just find a clean, used bed. truck beds are a dime a dozen, finding a clean one can be hard, but there out the and there fairly cheap.

 

[Shran]

I have seen all kinds of weird shit done with body filler and fiberglass. 99% of it should not have been done because it was a waste of time. My dad tried stuffing a bunch of steel wool into holes, then fiberglass over that. Well as you can imagine that turned into a big rusty glob after about a week in the salt, so then he pulled that and sprayed expanding foam, then used body filler over that. Eventually the whole section he played with fell off. He would have been time and money ahead just cutting the rust out to begin with.

 

[85DANGERanger]

I have seen all kinds of weird shit done with body filler and fiberglass. 99% of it should not have been done because it was a waste of time. My dad tried stuffing a bunch of steel wool into holes, then fiberglass over that. Well as you can imagine that turned into a big rusty glob after about a week in the salt, so then he pulled that and sprayed expanding foam, then used body filler over that. Eventually the whole section he played with fell off. He would have been time and money ahead just cutting the rust out to begin with.

ive heard of people using the expand foam as filler, but steel wool?? thats a first. that stuff rusts almost immedetly.

 

[ZMan]

ive heard of people using the expand foam as filler, but steel wool?? thats a first. that stuff rusts almost immedetly.

at the restoration shop I worked at, we had a '38 Buick come in that had holes stuffed with steel wool, they were pretty big wads of it, lol.

 

[armadillon]

I know this is an ancient thread. I admit I just used expanding foam and bondo over it. But steel wool? I thought that would be obvious how quickly it rusts. It would seem that once the rust is completely cut out you could do the foam/bondo combo, but not add something which would accelerate the oxidation.

 

[Shran]

Well, some people have really stupid ideas, and some of those people actually follow through with them. I am admittedly nowhere near the 100% perfection level in anything I fix but I don't half ass things either.