What to do about a rusty frame?

[strantor]

My daughter and I are fixing up an old truck (91 Chevy S10) and the frame is rusty. We've got the bed off right now but no plans to remove the cab. I can't wrap my head around the rust on the frame. It's all surface rust, nothing bad at all, but it's the ENTIRE frame. Every square inch of it. It's like the frame is only a year old but never got painted. Or like every square inch of paint simultaneously fell off of it a year ago. How does that happen?

Anyway I don't know what to do about the rust. Anything I do is going to feel half-ash since I won't be able to get the front half. But I don't want to do nothing. Someone recommended coating it in ospho, but my understanding is that ospho needs to be followed up with paint or else it's worse than pointless; the rust will pick right back up where it left off and be worse than before. Is that correct? Or can I just spray ospho all over and proceed with confidence that I've done something better than nothing?

Can I just spray old motor oil on it to stop it progressing?

What would you do? This truck will probably only stay in the family for a couple of years until my daughter goes off to college in a newer vehicle and I either sell this or do a frame-off restoration on it.

 

[jaxs]

If you look at frames of cars and trucks more than a few years old,they are exactly as you describe. Forgetaboutit and move foward with mechanicals and noone will ever know the differene.

 

[ponytug]

If it were me, I would vote to cut your losses. If it isn't going to be with you long term, avert your eyes and move on.

If you really are considering a frame off restoration, I wouldn't do anything that is too hard to undo. (E.g. diesel/motor oil is ok, painting isn't, unless you have a local stripping tank.) Given where you live, it probably won't get too much worse in a few years.

My bet on the all over rust would be some beach off roading to sand things off and a quick dunk through some waves to get salt everywhere and the rust started. Or just a gentle dunk in storm surge. Whatever it was, it happened.

Have fun!

Peter

 

[RustyA]

Up North in the salt belt rusty frame means something different. 2004 models you can see through the frame, shackle supports rusted off with spring penetrating bed, fuel tanks held up with ratchet straps because nothing left of frame member supporting tank straps. That's frame rust!

 

[LouNY]

Given your intended usage I'd just coat the frame and the under body with fluid film or a similar product.

 

[Jstpssng]

I haven't tried it yet but this stuff https://www.amazon.com/Magnet-Paint...hvlocphy=&hvtargid=pla-4584207577478177&psc=1 is supposed to work good.

 

[dodge man]

If it really is just surface rust and it isn’t damaged, I’d use something like fluid film. They make kits for spraying it on.

 

[ROUSTABOUT]

I've got trucks all the way back to 1941. Frame never messed with and it's still fine. But, I have one that is bad. In the glove box I found papers from Michigan, so I understand.

 

[ChuckT]

Only one solution - IF & only IF, because of the effort and price involved, is to remove the frame from the body and the engine & running gear, strip and repair as needed, then high zinc primer then paint with "undercoating" (covers and still allow the frame to flex) then put everything back. Of course you could also do the smart thing and replace the frame with an after-market "box" frame and ... etc. But it doesn't sound like you want to

 

[bdhsfz6]

As others have said, unless you're doing a complete restoral on the vehicle, I wouldn't worry about it since you aren't going to keep it long term.

That being said, I would check the frame where the front suspension is attached. I had a 1994 S-10 where the frame rusted to the point where I had to weld on reinforcing plate. The truck had 120K hard miles on it and was stored outdoors before I bought it though.

 

[KennyG]

If it were me, I'd paint it with rust encapsulater and then frame paint on all the exposed areas. See Eastwood products for examples. I'd do it all with brush on paint. It won't cost that much and it's only a couple of days work. You can paint it with paint as quickly as with oil.

 

[3Ts]

Ospho converts the rust (iron oxide) to iron phosphate. The rust does not cling to the base iron, the iron phosphate does. The iron phosphate is a better coating than iron oxide in that it adheres to the iron and slows down the rusting, but it is not a top coat. It should be considered more of a primer than anything else. It's better than not doing anything, but it is not permanent either.

Edit: My approach is to use Oshpo on lightly rusted steel, then a zinc paint, followed by a top coat of paint. But, this is for structural stuff out in the weather. I've never done an automotive finish job and what I do is definitely not an automotive finish. For heavily rusted steel, I sand blast it.

 

[MossRoad]

How about some pictures?

One man's surface rust is another man's catastrophe. Pictures should show others what you have.

 

[Deere Dude]

After looking at my rusty frame of my dooly for a few years I talked to a couple trusted body shop guys and a car restorer. They pointed me to OReillys for some rust restorer and some sort of rattle can spray that is very tough. Four years ago I had to get the box off so it was the perfect time to coat my frame, springs, breakets etc. They turned out very nice and still looks great. Sad to say I forgot the name of it, but was made for frames.

 

[amhicks21]

Buy 2 gallons of black fluid film or wool wax (same stuff, different name) for 100 bucks add a pro spray kit for 100 bucks off of Amazon. Spend 2-3 hours spraying, and the underside of that truck will look beautiful for years. Once a year or two, spend 30 minutes touching up any spots that may have been missed. I have 4 vehicles with an average age of 26 years old that i drive all year and since spraying them, there has been practically no new rust. Im not the type to swear by a product but this stuff is the way to go. I also work for a company that runs 7 salt trucks and around 20 plow trucks and we use it on a bunch of equipment.

 

[Jstpssng]

Fluid film won't stop existing rust. It simply creates a layer between the metal and whatever might get onto the frame. There are other products which are supposed to actually interact with the rust and neutralise it.

 

[jjeff]

I remember when I was stationed in California, had to get new tires, the tire shop informed me my frame was rusted, expecting to see perforations I laughed at them when they showed me nothing but some surface rust. I started to think they were trying to scam me and wanted to buy my truck super cheap. Nope they weren't, non snowbelt folks think a little surface rust is the end of the world in some cases.

 

[Topzide]

Check out Black Star MROChem: We Have Your Chemical Solutions!.
Can be brushed, rolled or garden sprayer applied. Environmentally friendly! Photo of truck frame of my 2014 3500 Ram. Doesn't need a top coat but you can if you want.

 

[amhicks21]

Fluid film won't stop existing rust. It simply creates a layer between the metal and whatever might get onto the frame. There are other products which are supposed to actually interact with the rust and neutralise it.

Rust is iron oxide. Just iron and oxygen. If oxygen cant reach the iron, no new rust is formed. The reason that people think rust spreads like a cancer is because rust creates porosity. That porosity allows further exposure to air, water, and salt. If you saturate that existing rust with an air and water tight barrier like fluid film, new rust can not form.