james1

I just picked up a new-to-me truck as my daily driver. It's in great shape but spent the last three years in Syracuse, NY. Much of the undercarriage has surface rust beginning. This includes the entire rear differential housing, numerous spots on the frame, all exposed bolt threads, etc., etc.

I expect to own this truck for 20 years and to spend the foreseeable future here in GA where there's no salt, but I need to get the existing surface rust fixed.

Would spraying all the spots with a good liquid rust converter take care of it? From what I've read about POR 15, that product seems to be a rather thick coating and would therefore be overkill? (Although POR 15 is available in clear, so perhaps that is an option?)

TIA.

samiam4

Por15 is an excellent product. But you need to remove the dirt and oil.

If it is only light rust, rustoleum. Diff I'd clean w oven cleaner and paint w epoxy. If bolts are rusty, I'd replace them.
Brake lines might need replacing too.

M

NJTman

I've tried the rust converter route

I've tried the rustoleum route

I've tried the epoxy paint route

now what I do is to apply sulfamic acid mixture to remove the salt / winter chemical on the frame, pressure wash it, let it dry, than any spots that I see bare, or I can scrape the blistering paint off of, I then spray with white lithium grease. So far, it's working, but it's only been 4-5 months.


RC, Rustoleum, Epoxy all failed. Reality here is that a layer of grease prevents the rust until that grease is removed. The paints all blistered, even after scrubbing, rust coverter, primer, paint, etc.

I wish you the best no matter what you decide to do, as I've not yet been able to find the "perfect solution".

MrFusion

My cousin painted a rusty jeep YJ frame with 2 coats of Chassis Saver paint. Its been sitting outside for 2+ years and no rust has come through. I'm going to use it on my W250 frame and see how it goes. If it fails I'll probably go the NJTman route and spray oil or Fluid Film all over it every year.
When I lived in NH spraying Fluidfilm, bar oil, or used motor oil all over the the underside of vehicles every year or two was pretty popular and relatively effective.

NJTman

Chainsaw bar oil works well, and sticks pretty good.

FF works good for a while, but washes off quite easily. I used to buy it by the case, and spray the plow with it, but that was a waste of money... White lube seems to hold on longer..... and visually you can see where it lies..

Still sucks either way..

flyboy129

Given what the OP stated, if he plans on keeping it in GA and doesn't see much in the way of salted roads, I would replace bolts and hard lines, wire wheel or sand the frame (or sandblast), epoxy prime, then paint. Yeah, it doesn't last against salt in the northern US, but in GA, I'd do it. Then, if I needed to drive it in bad conditions, I'd spray the chassis down with oil. Or better yet, find an old gasser Dodge 4x4 and use it for just winter stuff.

james1

Thanks to all. The truck is nearly new with only 22k miles so replacing bolts and brake lines is not yet necessary. Ideally, I would simply like to get the existing rust stopped in its tracks -- if I could accomplish that, then I would be done for good so long as I remain here in Georgia.

Fluid Film is too easily washed off and POR 15 seems to be a thick coating that I fear would simply cover the problem (as opposed to stopping it). Would it work to hit all the spots with a rust converter and then come back a week later with some rattle can Rustoleum? Would the areas hit with the rust converter need to be pressure washed clean before painting them?

Again, TIA.

oliver foster

I used bar and chain oil thinned down a bit with some diesel fuel to help it creep into the cracks better.
I wash everything down, let it dry, spray it down with the oil mix, run it for a year and repeat.
I use a Schultz gun and my air compressor turned down to 40 PSI or so.

Unless you get rid of the rust, covering it with paint is just making it look better as it happily rusts away under the paint.

Alec

Pressure washed clean is not even close to good enough in my opinion and experience. Degrease everything, then wash everything with a sulfamaic acid solution, (or just buy salt-away from Eastwood or a similar company). Then remove any loose rust by scraping, sanding, or sand-blasting. (Wire wheels fold rust into the surface of the metal and polish it)

In my opinion, industrial Rustoleum over mechanically cleaned rust will last much longer than any rust converter. I have never seen a rust converter work: they don't convert all of the rust, and they don't create the best paint film, and they don't have the best adhesion.

Rust converter and poorly prepared paint are harder to fix in the future than fluid film, grease, or oil.

FWIW -- I just moved to VA from MA.

MrFusion

I'm a little afraid to sand blast the frame on my truck. It might disappear!

james1

This is exactly my fear of covering the rust with something thick, such as POR 15.



Thanks; this seems sound advice. I do have access to an auto paint store that sells a DuPont self-etch primer in rattle cans made for professional use (and runs about $22/can). I'll use that covered with a Rustoleum top coat and see how it holds up.



Thanks again to all.

j_martin

This stuff should work to remove rust, including that pounded into the surface by wire brushing. It can't deal with oil or grease, so de-greasing would be needed first.

It's designed for immersion, but good results have been had by covering the parts with soaked rags covered with plastic to prevent evaporation. I suspect a repeated light spraying to keep the part moist might work as well.

Evapo-Rust Rust Remover - Evapo-Rust Super Safe Rust Remover

City Rat

Ok,
POR 15 works. If you use it as directed. First you have to media blast/wirewheel or brush the surface rust and dirt off. Then hit it with the degreaser solution and the prep stuff once dry there will be some new flash rust on bare metal. POR 15 likes that, bonds to it, chemically changesthe rust so that it is no longer active. Moreover the difference between POR 15 and alot of other products is that it gets harder, not softer, when exposed to mosture, making a harder sealant for your frame. Last you can follow the directions and thin it if you like. I have used this in the restore of an old 4x4 and am about to use it on the frame of my 99 2500. there is a lot of discussion on the restoration forums about this topic POR15 vs. galvanizing, vs. powdercoating frames etc etc. pretty much everything else has an Achilles heel that POR does not. POR does have one weakness, UV rays. So if you are going to use it on the truch roof or a rusting truck bed, POR says basically apply a coat of regular paint after it cures and problem solved. On the grease or petroleum solution to your rust problem, it works...for a while. You have to commit to doing it periodically, keeping after it if you go this route. I have said this elsewhere but worth repeating here, I knew a guy who everytime he did an oil change would use his used motor oil and brush it all over his frame. It worked as long as he felt like doing that chore every so often. I have no idea how long the grease/used motor oil fix lasts, just know that it is a good temp fix for sure. I have no affiliation with the POR guys, just a satisfied customer. Hope this helps. Good luck.

2mtrucks

CRC heavy Duty Marine Corrosion Inhibitor...originally designed for saltwater marine applications...look up JMS Marine supply. Only product I have used that works. Leaves a semi clear paraffin-like film that lasts about a year....doesn't spray off at the carwash. I use it on every vehicle I own. My 2012 Ram plow truck looks the same underneath as the day I drove it home from the dealer.

Jim Lane

This has got to be some government conspiracy, man.

Spraying chemicals on the roadway knowing it is going to rust the people's cars away so they can sell them a new one.

How many years are the average life of a new car on the east coast?