Minor frame TLC before new bumper - POR 15 enough?

[GerLC100]

Hey guys

Prepping everything for my soon to come Dissent rear bumper.
As I need to cut the crossmember and have to apply some paint either way I want to hit whatever I can on the frame so make it shiny again.

Would you just clean it off with a regular brush, degrease and paint?
Or treat the “rust” before paint?

 

[delz05]

Wash, scuff pad, rust converter primer and then semi gloss black paint... will make it look brand new!

 

[excessive]

the overall consensus is that por15 is not a very good product.

 

[GerLC100]

Heard about it, but I also think it’s there’s some opinions in it. In another offroad van forum everyone is using POR for these “repairs”, van floor protection and similar.
I guess as it’s a) not a major damage and b) I’m in California and don’t need to complain about rust it’s at least a good enough solution.

Main question for me is treat before painting or not. Most people from the rust belt would surely be happy to see this kind of frame after 25 years

 

[delz05]

Heard about it, but I also think it’s there’s some opinions in it. In another offroad van forum everyone is using POR for these “repairs”, van floor protection and similar.
I guess as it’s a) not a major damage and b) I’m in California and don’t need to complain about rust it’s at least a good enough solution.

Main question for me is treat before painting or not. Most people from the rust belt would surely be happy to see this kind of frame after 25 years

This is all that frame needs... Wash, scuff pad, rust converter primer and then semi gloss black paint... will make it look brand new!

There is very little, if any iron oxide showing, it looks more like mud spray. Until you wash and clean the frame, no one answer is going to be the best. But you are correct... I would love to see my frame in that condidtion, even after 5 years!

 

[kevgentile]

I recently did a section of my frame after the booster leaked out and stripped the paint of the frame...
Spray it down with Ospho first. Let it dry for a minimum of 24 hours. I swear by Rustoleum rusty metal primer, put 2 coats on 24-48 hours apart. The key with the RMP is cure time, the longer the better and more durable. Left alone for 2-3 weeks will result in a harder finish, longer even better. I've been using it for years and tried various cures times, anywhere from a few days to a few months. After a sufficient period of time hit it with 2-3 coats of Rustoleum flat black. Again, with 24-48 hours in between coats. The flat in the quarts have more of a satin finish that's closer to oem, when brushed on.

DO NOT use aerosol paints. The key is to use the quarts you can find at any hardware supply store. I always brush mine with a high quality oil base friendly brush. Just clean them well after use.

There will be mixed opinions on oil based paint. After nearly 30 years since my first project and experience with "rust sealing" paints, I have had the greatest success with RMP and good'ol oil enamel. There are a bunch of vintage/antique specific forums that discuss this and swear by the same approach. There's also a lot of mention of its use on steelsoldiers website, but they topcoat with latex acrylic enamel aka house paint.

Even better than the results is the price, $16 a quart vs the over priced rust sealers.

 

[kevgentile]

If you have little to no oxidation leaving it alone could be a good idea too. It all depends on how much work you want to do. There will be a lot of areas you'll have a hard time getting to, especially between the body/floors. Also, there are a lot of hard lines, brackets, clips, nuts, and bolts that are secured against the frame that you'd want to remove or pull away from it to offer the cleanest results.

When I did mine I decided to remove everything attached to the frame to get an oe finish, it was a bit of a hassle and that was only a couple feet of frame.

 

[jsloden]

As speaking from expirience as someone who's used por-15, I would not use it on lightly corroded areas like what you have there. If the prep work isn't done to the T moisture can get in behind the por-15 and rust and rot out things completely. For what you have there simply scuff it with a pad and put a couple of light coats of rustoleam and call it a day. Also, if you do ever por-15 on anything DO NOT GET IT ON YOUR SKIN. They don't emphasize this enough on the packaging. I have used every chemical known to man on various things over the years and with enough gasoline and scrubbing I have gotten everything off except this stuff. There is NOTHING that will take this stuff off. MAKE SURE YOU WEAR GLOVES. You've been warned.

 

[kevgentile]

As speaking from expirience as someone who's used por-15, I would not use it on lightly corroded areas like what you have there. If the prep work isn't done to the T moisture can get in behind the por-15 and rust and rot out things completely. For what you have there simply scuff it with a pad and put a couple of light coats of rustoleam and call it a day. Also, if you do ever por-15 on anything DO NOT GET IT ON YOUR SKIN. They don't emphasize this enough on the packaging. I have used every chemical known to man on various things over the years and with enough gasoline and scrubbing I have gotten everything off except this stuff. There is NOTHING that will take this stuff off. MAKE SURE YOU WEAR GLOVES. You've been warned.

Yeah, these rust encapsulators are evil to the skin. Back in '95 I did my '65 Mustang with Bill Hirsch's Miracle Paint (my favorite of them all) and was stuck on me for several weeks.

Like you said, unless properly prepped and etched these paints will fail and come off in sheets. Not worth it when considering cost. I did recently use KBS coatings Rust Seal on my custom motorcycle hitch carrier. Very durable compared to POR15.

Another reason I wouldn't use these on my frame is due to the level of sheen. Way too much gloss in them all, unless top coated with a flatter paint. Bill Hirsch has the correct chassis paint to compliment his Miracle paint. Rustoleum's flat black in the quarts/gallons are perfect when applied by brush.

 

[GerLC100]

Sorry, took some time to respond, busy with work.

Here‘s a pic of the frame behind the rear passenger tire after cleaning.
I‘m kind of tempted to not do anything to it…
1999, 280k miles in CA…

 

[kevgentile]

That frame will outlast you. I'd leave it alone. once you start sanding and painting you'll just expose it to problems that don't currently exist.

 

[John McVicker]

I have found Por 15 to be excellent and extremely durable. Painted the frame of my 40 sometime in the late ‘90’s & it has held up very well.

@GerLC100 your frame picture in post 10 looks excellent, depending on what/where your future plans are, it doesn’t really need a coat of anything. But a coat can’t hurt…mine?? I’d put some Por 15 on…personal choice.

 

[GerLC100]

I have found Por 15 to be excellent and extremely durable. Painted the frame of my 40 sometime in the late ‘90’s & it has held up very well.

@GerLC100 your frame picture in post 10 looks excellent, depending on what/where your future plans are, it doesn’t really need a coat of anything. But a coat can’t hurt…mine?? I’d put some Por 15 on…personal choice.

Yep, I think this is what I'll do. Just stay in the POR system with metal prep and then coat a layer... it will surely not make it worse and the frame looks like it's keeping up another 25 years

Will report and post pictures afterwards, but will take some time.
Picking up my roof rack and front bumper next Friday and the rear 6/19.

On the front I got to surely take care for some rust as it had a coolant leakage in the past (PO replace everything but the crossbeam/ bar under the radiator should look nicer when the new Dissent is on

 

[GremlinMobile]

Yep, I think this is what I'll do. Just stay in the POR system with metal prep and then coat a layer... it will surely not make it worse and the frame looks like it's keeping up another 25 years

Will report and post pictures afterwards, but will take some time.
Picking up my roof rack and front bumper next Friday and the rear 6/19.

On the front I got to surely take care for some rust as it had a coolant leakage in the past (PO replace everything but the crossbeam/ bar under the radiator should look nicer when the new Dissent is on

Enlighten me fellas. I thought wirewheeling the rust spots on the undercarriage and spraying Fluid Film is the preferred way in this community? How come the narrative in this thread is to use some kind of rust sealant and then paint? I thought paint is no good since a rock chip can crack the surface of the paint and moisture can get behind the paint, beginning rust, whereas something like Fluid Film creates a "self-healing" membrane that is resistant to these scenarios? Not arguing, just trying to understand this as I too have a bit of rust proofing in my near future.

 

[GerLC100]

My very personal take, not being a professional and especially not having a whole lot of experience!

All these things are extremely polarizing! and you never know how much care whomever took. All paints are adhering to surfaces the same way that adhesive does (and this is the industry I'm in).

Point 1:
Adhesion happens on the first few nm of a surface. Put any contaminant on and no material will stick as well as on very clean surfaces.
Yes, there are VERY specific materials to deal with oiled surfaces, but that is also very specified which oil in which layer and then the adhesive is specifically developed to take this amount of oil up.

Point 2:
Any rust is always on top of "fresh material". Even an "untouched" aluminum oxide layer on 80/20 bars or so is changing! So for perfect results you want to have it reproducible and fresh --> remove rust

Point 3:
All material chemistries have their pro's/ con's. Some have better bulk properties to resist water ingress, some not. Yes, oil based paints typically have a better resistance as the oil already has hydrophobic properties.
I also read a few threads where people did a proper full scale POR15 treatment and then used Fluid Film as final barrier layer being more flexible and less chipping.

Point 4:
I personally don't have real rust, just some "imperfections". Seeing this frame 25 years in CA I'm very sure another layer of anything will not lead to a downturn in longelivity.

Point 5:
ih8mud is not the only forum. For my van I'm in a different forum and the people always use POR in all areas without direct sun light (polyurethanes are not UV stable, which is why your PU windshield adhesive is covered by the blackprint on the windshield; the point design you can find on most cars is only to make it visually nicer appearance ).
A friend from Michigan is in the hot rod scene: using POR15.
I met some jeepers using POR15 on their (non daily driver) rigs and they're happy.

Point 6:
I got POR 15 left :-D

 

[delz05]

You will not have any issues using POR15 or any topical sealer, as long as you take the needed prep steps prior to application.
All of the above mentioned coatings and sealers will get the job done.

If you want to be absolutely certain you will have no issues as time goes on... get the truck up on a lift and blow all the debris out of the interior of the box frame, suspension components, cross members, bumper re-inforcements and radiator support. Once those areas are clear and cleaned, spray Fluid Film or WoolWax INSIDE those areas. I use both flexible and straight wands to get into all the areas after I rebuild the frames here in the Boston area. Over the course of 2 to 4 hours, I will spray in upwards of 4 quarts, INSIDE the frame and such. After, I will prep the exterior for either a sealer, paint or hard coat, in order to preserve the external repairs completed. Grind, scuff, sand, hit it with a needle gun, what ever your truck requires (it does not look like more than a sand, scuff and rust kill prime). We go to the extreme at my shop... gas tank down, exhaust out, suspensions dropped etc... in order to do a COMPLETE inside and out frame restoration and preservation.

It's never worthwhile to half-ass the repairs. The more time you invest, the better the results and the happier you will be.
Good luck with it and post up some before/after pictures once completed!