Bare metal epoxy primer for truck frame

[crazyal]

I would look into a product from International paint. It's called Pre Prime 167. It's a clear liquid that's designed to be painted on rusty surfaces that can't be properly prepared. The first time I saw the results were at a local paint dealer. They had an I-beam that was clearly rusted before coating half of it with Pre Prime. They then left it next to the ocean for a year. The unprotected part was terrible but the protected side looked like someone that morning sprayed clear paint over the existing rust. It's not a product like POR15 that converts the rust. This stuff soaks through the rust and down into to the steel. I used it on a car trailer for a friend about 10 years ago that was badly rusted. The stuff works great.

 

[Snobdds]

I see a bunch of $$$$ going out the window...

 

[Hay Dude]

I see a bunch of $$$$ going out the window...

It happens. I’m not going to cry about it. Bt noon tomorrow, all the rust jacking will be removed and we will be back to sandblasting.

No guarantees, but saving a truck from truck salvage yard is rewarding. If I had driven 9 hours to inspect it first, I probably wouldn’t have bought it, but I didn’t.

Luckily, I paid a low price and sold the 10’ stainless steel bed and spinner for good money, so I should still do pretty good.

But the last ”northern” truck I ever buy, that’s for sure.

 

[Hoss710]

I used to work for a shop where we made truck bodies. This is going to sound crazy to some. but we would take the brand new bodies outside. and spray them down with a hose and let them sit overnight. In the morning they had a light coat of rust on them. then we would bring them inside and bake them for about a hr to get the moisture out. then paint them. We never had any paint issues. that company still does that today 30 years later. And has yet to have anyone complain , or have issues with paint coming off or rust issues.

 

[Hay Dude]

A light rust haze will grip paint.

Next question after I have the gap cleaned up of the rust jacking.
My plan is to: completely clean the gap of jacking, blowing out with air gun and treating gap with rust kutter (Ospho).
Then I will “flood” the areas with fluid film or used oil, theorizing it will creep & seep down between the frames and possible drip out the bottom.

When that is done, that area is bound to attract dirt which will hold moisture. I can’t imagine theres a flexible caulk that will work. However, “Quad” caulk really sticks and lasts.
Not sure if I seal the opening of commit to raising bed and cleaning it annually?

Sealing closes off the upper gap to further treatments though.

 

[spitter]

I have a 99 and 2 01 super Dutys I did with Ospho and rustoleum black industrial 5 years ago that are still intact today. Put on about 300 k miles combined in the heart of the rust belt daily drivers. At under $500 for all three trucks, it's not bad for a [homeowners' gimmick]

A mason friend had his dump [professionally] done with POR for $7500.00 that is peeling off in sheets. And a sparky that did his bucket truck with linex that is flaking off also at the cost of 8k.

As far as the rust jacking goes, I know a guy who clamped it together and welded together. He painted his with steel it paint $$$$ it seems to be holding up well but only done 2 years ago. Done on an International Rolloff.

 

[mrmikey]

Ouch, that is a big gap but I've seen worse.

I think if I left it in, the fames would separate so much they would crack

Yeah, you wouldn't want to leave that in there, It'd act like a big sponge

“Quad” caulk really sticks and lasts.

Mehhhh, I wouldn't. There's no caulk made that will work (least I don't think there is). Not only that you'd never get it sealed enough to keep the crap out, it'll wick in thru bolt holes, rust spots that were missed etc. You'll be able to get something sprayed/flooded in there to get the inside coated no problem, if you leave it open you can keep spraying, over time, something in there 'till it runs out the bottom.
Also where the top flange is bent up it's going to make it miserable to get a body sitting properly. Did you try bending the flange down at all with the same bfh? It doesn't look to be thinned out to bad tho, least in the pics it doesn't. It's not a a strength issue yet, just a mechanical one.
Worst thing about the flange if you can't get it flattened out, the dump body will wear thru the edge and thin it out in time unless you use a subframe.
What we ended up doing when we went to single frame was use a strip of 3 x 3/8 flat between the body and the frame as a wear strip. We actually ended up replacing a couple of top flanges of trucks where the wear was too bad to the point the edge of the flange was a knife edge.
If you can't get the flange straightened and don't want a subframe, you may be able to do the same thing but using a smaller strip as a spacer on the outboard edge to level it out.

A mason friend had his dump [professionally] done with POR for $7500.00 that is peeling off in sheets. And a sparky that did his bucket truck with linex that is flaking off also at the cost of 8k

That' what I have against 'hard' type undercoating, I think they cause more problems than they solve.

As far as the rust jacking goes, I know a guy who clamped it together and welded together.

Don't know if I like that idea

 

[Hay Dude]

I’d like to bend the opening down, too. Just not sure how. I am a country boy and smacked the snot out of the upper flange. I got the rust jacking out, but it didn’t seem like it wanted to bend down.

I think that’s actually a good thing in a way because it means the steel still has some “spring” in it!

I really like the idea of welding an outer “strip” on the dump body frame rails to keep from wearing the inner edge of the flange! MrMikey you get a big thanks for that. Sounds like cheap insurance to me.
I think I’m sold on Rust Kutter, primer & paint procedure. Then flooding frame with fluid film periodically.

Keep ‘em coming boys. It’s gonna be an adventure!

 

[dodge man]

I think we are well to the point of overthinking it. If you’re sand blasting it just use a quality primer and paint. Maybe in a couple of years hit any questionable spots with something like fluid film.

 

[mrmikey]

I really like the idea of welding an outer “strip” on the dump body frame rails to keep from wearing the inner edge of the flange! MrMikey you get a big thanks for that. Sounds like cheap insurance to me.

You're very welcome .
Actually I think you may have misunderstood. What I meant was the 3 x 3/8 flatbar goes on top of each frame rail on the chassis one piece each side front to back so it's flat across side to side to give you a flat surface. The extra piece of flatbar (possibly 1 x 3/8 or 1/4 depending on how much to fill the gap) is welded to the underside of this to fill in the gap on the outside to the corner of the existing frame rail.
This is what I was meaning, a bit exaggerated but I' think you get the general drift :

I got the rust jacking out, but it didn’t seem like it wanted to bend down

That's the problem with HSLA steel, it's springy especially when you're beating against something that's not completely solid.