Truck bodywork Question

[Vera]

The cab roof of my '91 truck has been rusting quietly for the 8 years I've owned it. I think the previous owner scraped it under a low roof or something and did a poor repair/paint job. Anyway, it needs to be fixed so the roof doesn't fall in over my head one of these days, and I need your input on how best to do it. I don't have a grinder, and I'm not strong enough to sit up there for days with sandpaper (if that's an option)... needless to say, I also can't afford to take it to a body shop So. What do I do? If I pour CLR on it to dissolve the rust, will it damage the (rotten) paint on the rest of the truck? How can I be sure that all the rust is gone before putting primer on it, if that's the next step after getting rid of the rust? As you can tell, I know nothing about body work... help, please?

[fordy]

..................Vera , it depends on how big the rusted area is. Before you do any attempted repairs yourself , take it to a body shop and let them look at it and quote you an estimated cost . If , it is a small area , you maybe able to remove the rusted metal and epoxy and\or bondo "in" the hole and simply repaint with a spray can of paint that closely matches your color , ...fordy...

[herefordman]

I wouldn't worry about it too much, in Arizona its dry enough to not really be a big deal, the roof won't fall in on you no matter how much you think it will.
But if it bugs you, just scrub it down good with a stiff wire brush, and then paintbrush on either a marine paint or just a heavy rust paint like Rustoleum, as long as the area is sealed from air the rust will stop where it is for at least another ten years.
Don't thin the paint down just use it straight from the can, the thicker the better.

[uncle Will in In.]

Rustoleum makes a liquid to put on the rust before painting that kills the rust. Comes in a bottle and spreads on with a brush. Makes the rust turn black. Then slap a coat of rustoleum paint on it. Either spray or brush. White will be cooler in the cab. I put the liquid on a steel entry door with a piece of foam rubber. It works.

[Ozarks_1]

It's likely typical bondo won't hold due to vibration, changes in temperature, etc.

I suggest using a wire brush to scrape the heavy rust off ... then get some brush-on chemical rust converter (I use 'Rust Converter' by Klean-Strip, available at Wal-Mart - you should be able to find something similar at most auto supply stores as well). The rust converter will chemically change the rust to a hard paintable black primer.
If you have any rust through in the roof, a small fiberglass repair kit (you can find it where you find rust converter) would handle the job nicely.
Then you're ready for paint.

If you're wondering how long metal will stay rust free after being treated with rust converter, I have no clue. As a simple experiment, I treated a small area of an old plow about three years ago ... and the rust hasn't come back yet!
I've used fiberglass to repair everything from auto bodies to grain bins to fuel tanks. It's fairly easy to work with and holds up well.

[Windy in Kansas]

What, a sun roof is out of the question? You're having one handed to you and you are turning it down.

Depending upon the vehicle you may just want to control that rust as others have suggested. The rust stoppers work great. Rustoleum has a zinc oxide primer that will work similar won't work quite as well as the other rust specific products.

Sanding rust down isn't a real tough job. Wire brush off what you can, then use wet/dry sandpaper with a trickle of water or dipped periodically in water to do the sanding. The water keeps the material washed away to keep from clogging the sandpaper. Start with an agressive grit, then work to a higher numer which means a finer grit. Then stop the rust, fill the area with body putty if needed, file or sand the body putty smoothly, prime, then final paint. Try real hard not to make any area of body filler very thick as it will tend to chip out.

If you already have holes in the roof you may wish to stop the rust, then pop rivet a piece of tin over the area, then fill in and level with filler around the edges, sand, prime and paint. Not a pretty fix, but would last a good long while depending upon how think of tin you use. A chunk out of another vehicle would be best, the older the better as it will be thicker.

Good luck.

[comfortablynumb]

if it hasnt rusted thru yet....

a wire brush and a can of spray paint
or
I used to use good house paint and a brush.

if you have a hole, wire brush it till its clean, butter the edges of the hole with bondo then lay a scrap of screeen on the hole then skin more bondo over it till the hole is covered... wire brish the bondo after its hard to the touch and it will sand off easy...

if there is no hole.... paint will fix it. the rust kill liquid works well.

foundation coating I really like, but on the roof the sun will just keep it sticky.

now if you wanna keep the paintjob nice, dont ask me nice paintjobs just give people another reason to steal your truck.