So my Duster is mostly Rust Free...

[HaFa1]

Have a '73 Duster. Floor panels, doors, quarter panels, hood/trunk, and frame all have no rust or a little surface rust. Except for the roof and ceiling, I think it might've been sitting somewhere where a bunch of water was trapped in the car and caused the ceiling to rust pretty bad.

Talked to one person about it and they said I should just cut off the top and replace the entire thing, which I wouldn't be opposed to but for now I just want to keep it at bay while I update the interior, enjoy it, & build up a new engine.

I have some photos below of the roof and the ceiling, and would GREATLY appreciate any advice on what I can do to just slow it down for a year or two. Ideally I'd like to throw in a headliner just to cover it up but I'm wondering if I should sand the ceiling down a little or spray something on it before I do that?

 

[RAT ROD AL]

I have found citric acid in powder form ( cheap on the web ) to be the most inexpensive way to remove rust. On the top side you could soak a couple towels in citric acid/water solution and keep it wet for a day or 2 and rinse and scrub it off. then kill it with baking soda/water solution then rinse it off ! Then paint with a good rust paint.

 

[barbee6043]

I have used a phosphoric acid solution called Ospho. A gal is about $30 now days and a qt. maybe $15. A qt. will be plenty. I would hit it with a WIRE CUP on the right angle grinder ( pay attention) so as not to make HOLES but to clean the pores in the metal somewhat best you can. Blow it off and soak it heavy with the Ospho. LET it sit 24 hours and repeat. 2 applications. THEN wet it real good again with the Ospho and sit for only 4-5-6 minutes NOT in the sun. While still WET, hose it off good and wash with soapy water to neutralize the acid. The rust will eventually turn black ish and a dust of phosporous will be leaft. Blow off with compressed air so as not to flash rust. Wipe with a wax/gease remover. The real stuff. Some people use brake cleaner, some the good auto window cleaner (I forghet its name). LET it sit anopther day to be sure totally dry. Go ahead and remove the roof gutter old seam sealer. (OK so I can be ananl) I like to use a [good expoxy primer, some call it a direct to metsal fromer/surfacer. I like Soluthern Po;lyurethanes. The good PPG is high.
WHY all this carefulness!? Because some epoxy primners can react to an acid (in the epoxy maybe?) and in particular OSPHO. It can react months after applied.
If it does you will know!!

If it had a vinyl roof, there would be HOLES ! Look like it sat in the sun forever and Ok. acid rain got it some!!

 

[HaFa1]

I have used a phosphoric acid solution called Ospho. A gal is about $30 now days and a qt. maybe $15. A qt. will be plenty. I would hit it with a WIRE CUP on the right angle grinder ( pay attention) so as not to make HOLES but to clean the pores in the metal somewhat best you can. Blow it off and soak it heavy with the Ospho. LET it sit 24 hours and repeat. 2 applications. THEN wet it real good again with the Ospho and sit for only 4-5-6 minutes NOT in the sun. While still WET, hose it off good and wash with soapy water to neutralize the acid. The rust will eventually turn black ish and a dust of phosporous will be leaft. Blow off with compressed air so as not to flash rust. Wipe with a wax/gease remover. The real stuff. Some people use brake cleaner, some the good auto window cleaner (I forghet its name). LET it sit anopther day to be sure totally dry. Go ahead and remove the roof gutter old seam sealer. (OK so I can be ananl) I like to use a [good expoxy primer, some call it a direct to metsal fromer/surfacer. I like Soluthern Po;lyurethanes. The good PPG is high.
WHY all this carefulness!? Because some epoxy primners can react to an acid (in the epoxy maybe?) and in particular OSPHO. It can react months after applied.
If it does you will know!!

If it had a vinyl roof, there would be HOLES ! Look like it sat in the sun forever and Ok. acid rain got it some!!

Thank you for this! Can you recommend what I should do for the interior part? or should I try to do the same.

 

[Duster360LA]

Agree with barbee6043 on the cleanup process. After cleanup, consider painting the surfaces with POR to keep rust in check. Definately remove the roof rail gutters and inspect them. My 74 had a vinyl roof and the rust wasn't too bad on the top, but the drivers side rail (covered up by the roof rail when I inspected the car) was a mess. I had to find a donor roof rail to replace that section and it was a pain. And if you do eventually replace the roof, make sure your donor is a 72-76 Duster roof that takes the one-piece headliner.

 

[TF360]

Yea, you need a Rust Converter product. Eastwood sells it, Ospho is pretty good, Rustoleum is pretty good too. Don't get it in a spray can though.

 

[mopowers]

The underside of the roof panel on my 66 looked similar to yours. I ended up hitting it with a scotchbrite roloc disc than treating it with phosphoric acid. It was quick an worked great. Then just a quick rinse with water and wipe down and it was ready for some rattle can primer. No need to use baking soda if you rinse it well enough with water.

For the areas with holes - you'll need to replace the metal obviously. Just take it one piece at a time. You'll get it!

 

[RedFish]

I've got some rust converter stuff that I would use there. Water base. Odorless. Harmless. Pump spray. Throw it on any ol' way. They say it's derived from acorns. Once it's hidden, no one knows but all of us.

 

[barbee6043]

Might I add, be careful leaving Ospho on any chrome or stainless for any amount of time. Wash it off or if you get it on there, be sure it is neutralized. I would apply Ospho to that inside of roof also, once to sanded it best I could. I have used and like BodySchultz for decades. Probably a pre runner of maybe bed liner?. A great undercoating. You can find a gun for your compressor to spray for cheap if you look. Make sure your air pressure in NOT too much, don't ask me why I know. I would also spray it with a good epoxy primer, before the undercoat. I hate doing headliners, and don't go there anymore. But I am not a car show guy.

If I ever find a pro body guy that recommends a "rust convertor" , then I will use some. JMHO

 

[TF360]

Barbee, Ospho is a rust converter