Por-15 on roof

-
R

rburger

New Member
Joined
Dec 12, 2023
Messages
4
Reaction score
2
Location
Tennessee
Has anyone ever tried Por-15 on the roof after a vinyl top has been removed?

I have a 71 Swinger and the vinyl was removed and the top has pitting all over no rust holes.

I have sanding down to the metal and I was thinking about trying Por-15 to protect and help fill in the pits.

Question is can I apply primer on top of it and is Por-15 sand-able?

I plan to paint the top and not go back with the vinyl top.

Thanks in advance!
 
It sands about like concrete! Best bet is to get the top down to bare metal, treat the pits with rust remover like Evaporust or Rust 911 and them put epoxy primer on it.
 
Rustoleum rusty metal primer
7769830_0819_SPP_12oz_RO_StopsRust_RustyMetalPrimer_480x480.png
Several coats then sand and paint as you wish
 
POR 15 has its place. The outside of a car is not one of them. All rust must be removed before application of primer. Rust starts forming immediately on bare metal. More so in Missouri than Arizona. If you can not get rid of the rust before turning things into swiss cheese, then it need to be replaced.
 
Bodyperson said:
POR 15 has its place. The outside of a car is not one of them. All rust must be removed before application of primer. Rust starts forming immediately on bare metal. More so in Missouri than Arizona. If you can not get rid of the rust before turning things into swiss cheese, then it need to be replaced.
Click to expand...

On oil rigs where it was designed for... not automobiles.
 
Jim Kueneman said:
On oil rigs where it was designed for... not automobiles.
Click to expand...
I myself, do not have a problem using it on automobiles in certain situations. A good example is let say, extending the life of a 2000 truck. The inner rockers have surface rust and I am replacing the outer rockers. I'll hit it with the blaster to get rid of the loose stuff and then encapsulate it. Hose it down with Like 90 and it will last longer than the rest of the truck. It has a bit to do with economics too.
 
Last edited:
Bodyperson said:
I myself, do not have a problem using it on automobiles in certain situations. A good example is let say, extending the life of a 2000 truck. The inner rockers have surface rust and I am replacing the outer rockers. I'll hit it with the blaster to get rid of the loose stuff and then encapsulate it. Hose it down with Like 90 and it will last longer than the rest of the truck. It has a bit to do with economics too.
Click to expand...


Read the link I posted. It typically accelerate the rust that is covered
 
Jim Kueneman said:
Read the link I posted. It typically accelerate the rust that is covered
Click to expand...
I read it. I tested it. It works. I have to wonder if those failures were in super dry climates as humidity is its catalyst. I know it gets a bad rap from improper prep. I had one guy ***** because it peeled on stainless steel. LOL
 
Last edited:
On an episode of Graveyard Carz they were brushing POR15 inside of a torsion bar cross member while floor was out. The inside of the torsion bar cross member looked like shiny clean metal. Graveyard Carz said POR15 was ideal and would last forever. You would think they would have masked flange and sprayed epoxy primer inside cross member?
 
It needs tooth to work. You can grind on rust with a #24 grit grinder and the POR 15 will peel. A grinder just polishes iron oxide. You need too descale it and sandblast it for the correct profile or just use the existing rust profile. It has a learning curve.
 
AMC Diplomat said:
Rustoleum rusty metal primer
View attachment 1716177753
Several coats then sand and paint as you wish
Click to expand...

RustyRatRod said:
After speaking with Southern Polyurethane, my conclusion is that a well applied Rustoleum primer and paint is far superior to POR15. Even better are some of the epoxies they offer.
Click to expand...
Well guys, I would not have though that. You learn something new every day.
I usually DA the roof with 80 grit, clean it off thoroughly and then treat it with a product that contains Phosphoric acid. It etches the metal, turns the rust black and leaves a bluish haze to the metal. Then I lightly DA it one more time and prime and paint. Never had a problem. But I will try this Rustoleum stuff and let you know how it works.
 
harrisonm said:
Well guys, I would not have though that. You learn something new every day.
I usually DA the roof with 80 grit, clean it off thoroughly and then treat it with a product that contains Phosphoric acid. It etches the metal, turns the rust black and leaves a bluish haze to the metal. Then I lightly DA it one more time and prime and paint. Never had a problem. But I will try this Rustoleum stuff and let you know how it works.
Click to expand...
You can try it but what you have been doing is spot on. I have not had much luck with the treatments. I think it has something to do with the mineral content of my water. Lots of iron. I just have freshly sanded clean metal and epoxy.
 
If you have pretty good surface rust, it is best to treat it with something. Not a remover, but some sort of converter. When you're standing there looking at sparkly clean metal, if it had heavy surface rust on it, it probably isn't near as sparkly clean as you think. Unless you do apply some sort of treatment, you're just basically slowing the rust down. You can kill it, but it takes the right stuff to do it. That's my worry right now working on Vixen's outer wheelhouse and quarter, that I won't get it all. Well....that and the fact that I don't know jack chit about what I'm doing with the metal work. lol
 
I use navel jelly. I put it on and cover it with plastic wrap and let it sit to keep it moist. Scrub with a stainless brush, rinse and repeat until I feel it's clean enough. Scuff the bare metal, fill as required....epoxy primer. That's what I have been doing in my pitted areas, but I am no body tech.
 
CFD244 said:
I use navel jelly. I put it on and cover it with plastic wrap and let it sit to keep it moist. Scrub with a stainless brush, rinse and repeat until I feel it's clean enough. Scuff the bare metal, fill as required....epoxy primer. That's what I have been doing in my pitted areas, but I am no body tech.
Click to expand...
What brand of epoxy primer do you use?
 
The best epoxy paint I have found is PPG CRE-x21. It lays down thick and flat and is fully sandable. Its pricy but in my opinion the best out there. I think it was around $250 for 1.5 gal kit. You must reduce it, the activator is thick as honey. Here is a video I found on youtube.
 
I'm using PPG CRE as well on the whole car start to finish...even for the hi build before final blocking!
I've heard good things about it from trusted body shops. It isn't super easy to sand, but it's not difficult either.
How does it stand up...I'll tell you in a few years.It's currently on the '68 in my avatar.
 
Last edited:
I used the CRE on a corvette I repainted. The PPG rep. suggested it. I think it's kind of brittle for automotive use. I blocked it with #150 and recoated it with automotive approved surfacer. I used it on a car hauler that was blasted. Didnt even top coat it. Looks good at 4 years being outside.
 
ir3333 said:
I'm using PPG CRE as well on the whole car start to finish...even for the hi build before final blocking!
I've heard good things about it from trusted body shops. It isn't super easy to sand, but it's difficult either.
How does it stand up...I'll tell you in a few years.It's currently on the '68 in my avatar.
Click to expand...
Thanks bud, can you tell me what measurements I need to mix the primer and what PSI and nozzle size you use. Im going with your set up.
 
Here is a link to the tech sheet. https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiskNaV4Y2DAxVrEFkFHRTWAyMQFnoECBgQAQ&url=https://images.oreillyauto.com/parts/img/documents/ppg/cpcpb418+cre-x21+series+80513+fin.pdf&usg=AOvVaw30teTubReDT1QUVMqWhmzz&opi=89978449

We use it for a base and do bodywork over it. Then we use UPOL high build. Block and re-prime with high build up to 3 times. Sealer then color. I suppose you could but I wouldnt use CRE as a high build.
 
You must log in or register to reply here.
-

Back
Top