# Undercoat or paint frame??



## giggity (Oct 25, 2013)

Hey all, I have a 2002 Ram 3500 cab and chassis I bought last year that only has 45,000 miles on it, body is in good shape, but the frame is getting quite rusty in a few spots, I spent this past winter continuously soaking the frame with fluid film, but now I want to either paint or undercoat the frame so I dont have to keep doing this. Anybody care to share there opinions on what the best route to go is? I have found some undercoating called "undercoat in a can" that is supposedly suppose to stop and encapsulate the rust and is a rust preventive unlike normal undercoating that dosent do anything to stop current rust. Or should I be painting the frame? Any thoughts, thanks for any help!!


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## Randall Ave (Oct 29, 2014)

Is the body on, or off? Nothing will ever completely stop rust. There are some threads on guys doing this.


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## giggity (Oct 25, 2013)

Randall Ave said:


> Is the body on, or off? Nothing will ever completely stop rust. There are some threads on guys doing this.


Yes I know there is no way to stop it completely, since the truck has such low miles Im just trying to preserve it as long as I can, I would just like a product that has some sort of rust neutralizer or preventive in it. Body will be pulled off, going to power wash, and wire wheel frame prior.


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## Randall Ave (Oct 29, 2014)

I have an 02 ford f-350. Two years ago, took old utility body off. Replaced all the brake lines, all the rear brakes down to the tubes. Ground everything off the best I could and primed and painted it. Then installed a new utility body. I figured hopefully that will extend its life a little. And cheaper than a new truck.


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## Mountain Bob (Nov 12, 2017)

Most professionals use a 3 step system.I would never recommend undercoating,even the new stuff.Here are a few links. https://www.kbs-coatings.com/frame-coater-kit.html https://www.eastwood.com/paints/under-car-coatings/chassis-frame-paints.html


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## Aerospace Eng (Mar 3, 2015)

Get rid of any rust mechanically, use naval kelly or equivalent if desired to get into any pits, then prime and paint.


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## John_DeereGreen (Jan 2, 2011)

POR15 has done well on a couple rusty trucks we had back before I started buying new trucks.


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## Brndnstffrd (Mar 8, 2013)

Aerospace Eng said:


> Get rid of any rust mechanically, use naval kelly or equivalent if desired to get into any pits, then prime and paint.


Who is Naval Kelly???

On topic though I haven't done a frame yet but ive had pretty good luck with Rust Reformer on my plow itself. I just power washed it, wire brush/wheeled it and then power washed it again and then sprayed it. The black matched the sunfaded fisher black powder coat already on my uprights perfectly and the blade i sprayed yellow over. I should mention i used the Rustoleum black tinted automotive rust reformer, not the clear brush on kind or the regular rustoleum black one, since apparently that is different from the automotive one. I was only doing spots, not an entire refinish, but one year later and I haven't noticed any bleed through and the rust doesn't seem to be spreading. I know its not a permanent fix but for my money (about $30 for everything) I can't complain.

I haven't done a frame yet but I probably will be doing mine this year so I will be following this to see what others have to say.


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## Aerospace Eng (Mar 3, 2015)

......Stupid autocorrect. I didn't notice it before I hit send. ….

He ran a PT boat for McHale, leading a bunch of ne'er do wells who were facing significant sentences  


You are mechanically removing the heavy rust with the wire wheel. At that point, my gut feel is that it doesn't matter whether you use a good rusty metal primer or a "rust converter," but I have not done a comparison study.

I just don't believe in the claims of people/companies that say you can paint over heavy rust and stop rust from progressing.


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## Brndnstffrd (Mar 8, 2013)

Aerospace Eng said:


> I don't believe in the claims of people/companies that say you can paint over heavy rust and stop rust from progressing.


I agree. Thats why you remove the heaviest and then address the rest as well as you can. After wire wheeling I left it outside for about a week before rust reforming. My theory was for it to build up a light coating of surface rust where bare metal was exposed to help the rust reformer work better since they say it needs rust to function. In reality idk if that actually happened but it seemed to work well enough.

I know its not a permanent fix, but I am perfectly happy with spending $30 and a couple hours as a preventive measure to buy myself a few extra seasons before I have to do a more serious and thorough repair.

For my truck frame I plan on doing more research and doing a more thorough and permanent job. That isnt the place that I am willing to cut corners since my safety depends on it. I can get by without a plow, but without a truck, I'm stuck walking, and that's not gonna happen.


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## Mountain Bob (Nov 12, 2017)

Yes,I agree with most of the above posts,grind/scrape heavy rust off.The 3 step system I posted comes with instructions,there are at least 5 suppliers that sell this system.It works,I used to use it on horse trailers.I have no idea what Areospace is talking about,I have been in the automotive industry most my life,and have never seen a claim that--"I just don't believe in the claims of people/companies that say you can paint over heavy rust and stop rust from progressing."Maybe I grew up on a different planet.


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## OneBadDodge06 (Sep 22, 2004)

Did POR15 on my frame and top coated with Rust-Oleum plus hardener. I'm pretty happy with the results.


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## snowymassbowtie (Sep 22, 2013)

Used motor oil twice a year. Cheaper than fluid film and it does the same thing.


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## nediesel (Sep 4, 2018)

I just started using "New Hampshire oil underting" it's my first year using it but they claim there are rust inhibitors. For 140 you get a gallon of their oil and a spray gun with 2 nozzles. It sprays on really good I had about 2 drips and that was because I sprayed it up close in the rocker jams. It creaps so once you spray it on it makes it's way around. I like it, something to look into!


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## MIDTOWNPC (Feb 17, 2007)

Check out the por15 website 

The stuff works. 

I just ordered the base and top coat in white. I’m going to do a toolcat that needs some help


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## Ne1 (Jan 15, 2007)

MIDTOWNPC said:


> Check out the por15 website
> 
> The stuff works.
> 
> I just ordered the base and top coat in white. I'm going to do a toolcat that needs some help


Used this a few years back. Sandblasted everything, applied prior then applied. Very time consuming and it only lasted about two seasons before it started to flake.


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## scaping (Apr 12, 2017)

Like snowy said i use my old oil twice a year. I just sold my 2010 chevy guy couldn't believe there was vert little surface rust on it didn't hesitate buying the truck for 15k.


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## nediesel (Sep 4, 2018)

scaping said:


> Like snowy said i use my old oil twice a year. I just sold my 2010 chevy guy couldn't believe there was vert little surface rust on it didn't hesitate buying the truck for 15k.


What kind of oil do you use?


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## scaping (Apr 12, 2017)

nediesel said:


> What kind of oil do you use?


I just use my old oil from my mowers bob cats. I do all my own oil changes just save my old oil and use them on all my stuff.


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## Brettny (Jul 12, 2017)

I have seen undercoat where water got behind the coating. It was not a good sight. It kept the water right against the frame. It was like rust holding hands under that truck. 

I paint everything at least 3x. Im going to try spraying oil on it this year. I have a old 95 k3500 thats the oldest plow i see on the road in the snow.


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