Ok so I'm getting ready to cleanup the frame on my 1982 F150 2wd, and I'm not sure which direction I should go in as far as rust proofing the frame. The frame is in excellent shape as it has ziebart on it at the moment. My plan is to remove the ziebart and either prime it and paint it black or use some type of undercoat. What have you guys found that works best using an undercoat? Or prime, and paint it and touch it up each year? Thanks for any input!

 

Prime and paint you are guaranteed rust. I would clean everything up, use por15, then a two part epoxy and undercoat over that.

 

Yeah from what I've read the Por 15 seems to be the best solution. I'm just hoping it sticks to the frame well because I've heard so many mixed reviews on it.

 

In applying POR15 or any paint, prep is everything. Otherwise it'll stick to the dirt and scale you leave (and then fall off with it). Also POR15 doesn't stick to smooth surfaces well, so it's not a great choice for fresh sheet metal. But smooth surfaces won't be a problem on you frame! But from what I've read, sandblasting is a much better prep (leaves a rough surface for some "bite") than wire-wheeling (leaves a smoother surface).

 

Imo leave the undercoat off of it.
Nothing but shelter for moisture and rust.

Pickling raw steel with phosphoric acid will make it harder for oxidation to get a foothold.

If you must paint it I suppose POR is as good as any.
Too bad they can't get their **** together enough to include a proper UV inhibitor.

I'm tired of flaking rust and intend my own cosmoline like surface protectant.
Maybe nasty to work on but hopefully I'll have a lot less work to do.

 

The proper prep is key. Then RIGHT primer and paint

Do NOT use undercoat(it traps moisture and rots from behind)

I have used POR15 with pretty good results but not the best.

I have sense been using Master Series Mastercoat® Chassis Paints, Rust Paints & Chemical Resistant Floor Coatings And have been pleased with the application and the capability with other topcoats(UNLIKE the POR15)
It also is sandable and workable(UNLIKE the POR15) it is also UV STABLE(UNLIKE POR15)

But like all the "paint over rust" paints, they are not the best when doing that.(even though they CLAIM to)
You would be best to sandblast to BARE metal then Master Series as a prime then topcoat with chassis black. But I do realize most people do not have access to sandblaster nor the time to strip a frame bare. So for properly "etching" the frame some 120 grit sandpaper works well.

Just a FYI, in order to get the Zeibart off, you will want a HEATED power washer. Putty knife is a S L O W process and a regular power washer will not do it either.

I am currently in the process of doing a frame off resto on my 04 ranger. I did the sandblasting, Master series and Valspar tractor black. While Iw as not really concerned about looks(just wanted to preserve) It turned out to be SHOW QUALITY.

Oh and remove the bed to do the best prep possible(it is only 6 bolts and will save some much time and headaches)

I have had MUCH success with the process described above over the past 15 years

 

Lots of good info here. The reason I suggest undercoat over top of an epoxy (yes undercoat will trap moisture and cause rust IF over bare metal/crap paint) but it will stop rock chips and the epoxy is the best bare metal rust/salt/chemical inhibitor that can be had. Any typical paint will eventually chip if a rock or other debris cracks into it. Once a legit epoxy is cured, good luck putting even a scratch in it.

 

X2 on the steam Jenny for cleaning the frame.
The problem with paint (any paint!) Is that it will never get inside joints and flex will eventually allow moisture -bulk water, humidity or even just condensation- in.
Pickling solutions like Ospho don't have any solids or much surface tension to stop them.
I'd rather see some surface rust than have it eating away at the few places I can't access.
But then where I live has switched over almost entirely to brine & magnesium chloride.
That stuff seems 10X worse than the salt they used to use.

 

When we built replica Cobra and GT40 cars..we ALWAYS sprayed the new metal with OSPHO..(ACE Hardware)..Get it in every place you can reach..Let it set for a day......then wire brush any loose junk..then POR..(or equivalent). No more worries..