[Green Hornet]

About 2 years ago.....I laid some Por-15 on the tops of a sub frame back rails....as a test....and left it out in the weather....

It remained shiny for about 3 months....then went flat....(I realize that it requires a top coat)

I also realize that I probably missed the window for top coating...

What is the procedure (prep)...to get a semi-gloss top coat on it now.?

Thanks

[dhutton]

I would scuff it well with 80 and reapply. Or better yet a quality epoxy primer.

That being said I hate that stuff…

Don

[78w72]

yeah por15 is questionable for many applications. i used it on a front subframe for a 2nd gen firebird, fully sand blasted the frame to bare metal, then totally cleaned it, followed instructions on the can applied by brush, within about 1-2 years there was as a very dull greyish look since its not UV resistant.

have also used it on rusted surfaces like rear ends or a friends S-10 blazer frame that had rusted through the factory black coating... POR stands for "paint over rust", i applied exactly as the instructions say, wire wheeling the surface then cleaned... within about 2 years it started to rust through pretty bad in many areas. have also seen it applied to smoother surfaces where it actually flaked or peeled off. wont use it again after seeing that.

what i did on my t/a subframe after it basically failed was sanded it with 120ish paper then used good ol rustoleum paint in a can, has not shown any sign of rust in 12 years & still has the same sheen as the day it was applied. have used the rustoleum in a can or the "industrial" version in a can many times on auto frames or suspension parts with excellent results, & if it gets chipped or scratched its easy to touch up.

sand with a coarse grit paper but not too coarse to leave heavy scratch marks then use a good top coat like maybe eastwood or rustoleum for a easier to find paint, or a real automotive paint from a gun. or if you want to stick with POR products they make a top coat paint for it. in the future, dont use POR15, use a good paint or powder coat it.

[Formulabruce]

All that subframe needs is a scuff with a green coarse scrubbie. Epoxy would be ideal paint for it , or por top coat.
POR has worked Well for me.
I Always ETCH the metal first, wash with WATER, and DRY as a Bone before putting on A POR Thin coat.
POR Will peal on smooth metal..

[Green Hornet]

Thanks for everybodys input.....

Generally...on this type of frame....I would have wire wheeled the surface and gone with Rustoleum red oxide first...with their semi-gloss black on top...

This sub frame was not that bad...very lite surface rust......It was just a test.....

POR-15 does have it's place........on parts with advanced corrosion....

[dhutton]

POR has no place imho. Blast followed by epoxy always.

Don

[Formulabruce]

Originally Posted by dhutton

POR has no place imho. Blast followed by epoxy always.

Don

Do you REALLY believe you can get ALL, every bit of rust out in corners of a FRAME with a blaster?
ANY Tiny Black dots and you have OXIDES of Iron ( steel).
IF you said "Dipped" in acid , I Might agree....
I am a huge Epoxy guy and SPI user, BUT POR has its uses when USED correctly which 99% of folks do NOT do, including those who don't put it over paint.
There are places POR really works best, but I have seen it just sprayed over "everything" under a car with massive failures and this gives it a bad rep.
It cures best with thin coats and cures from the inside out as molecules attach to the metal AND Oxides.
I have had plenty of times the blasting didnt remove EVERY bit of rust, and rust came back in a couple years, THROUGH EPOXY bubbling.
I have blasted and POR a few Plow frames and its been the perfect solution.
That said, Even DP40 gets rust coming through and has to be redone.

[turbo69bird]

It’s called POR not prep it first super clean it then paint it with POR your not using it right if you do this and it won’t hold, that’s NOT what it’s made for, it’s made for making old **** look nice with minimal prep.
It’s made for keeping the rust from getting worse without a total resto.

I hate when guys use it wrong then bitch about it. It works great for its intended purpose . I’ve used it on plows that were rusty as hell fro. Rd salt and it held up where all the factory paint has fallen off and rusted to bits. Why woukd you sand blast and prep a frame then use something called PAINT OVER RUST. Use paint over prepped metal Or use DTM direct to metal.

[78w72]

LOL! its called POR but the directions from the manufacturer on the can clearly says you need to CLEAN the surface of all grease, oils, dirt or lose scaling rust before applying. It also says very specifically that it can be used on BARE prepped metal, which sandblasting is a very good prep that leaves a coarse surface for paints to adhere to, or even can be used on... SHINY POLISHED metal.

"Step 1: POR-15 Cleaner Degreaser (Formerly Marine Clean) removes grease, oil, dirt, and grime in one application without leaving residues, noxious fumes, or flammable solvents."

"Step 2: POR-15 Metal Prep (Formerly Prep & Ready) provides the best adhesion for POR-15 Rust Preventive Coating on any metal surface, including shiny polished metal surfaces. "

i explained my experiences with it, worked ok on my blasted subframe but looked like crap until i top coated it. but this was also like 12 years ago & my first frame off resto, just went by what i heard people say about using por 15 & verified with the paint rep at the auto paint store that sandblasting was the way to use it, had to remove all the old paint. but i also used it on a rusty frame that looked like old ***, cleaned it like por says but left it with a sound rust layer, it had bubbling & small rust spots showing through within about 2 years of normal driving in iowa seasons. so it didnt work very well at all on its intended purpose of painting over rust following instructions on the can.

i hate when guys dont read the instructions or descriptions of a product but then try & tell you youre doing something wrong or thats not how its intended to be used.

[JUDGE3]

I have used por a lot. I like the fact that in many areas. its great to have the liquid seep down between areas you can't see let alone get to. also brushing it on is great and it cures smooth also.

use gloss not semi gloss if you want the shine. me I just want the rust proofing. could care less if it faded.

its easy to touch up if you gouge into it.

I used soap and water, power washer and let dry real good. no issues.

[Formulabruce]

"Looked like crap"
That was never a claim of POR to be a superior looking
Finish, and all folks are different when it comes to that.
I have NEVER had good luck with POR on Any Smooth metal, and I don't recall that on their instructions they have titled " instructions for those that don't read instructions ".
Typically its brushed, but I have sprayed it and got it to lay down smoother.
POR forms a molecular bond with the oxides in the metal.
It has its place. Its great for Plow frames. Rusty truck frames..

[78w72]

"looked like crap"
just mentioning that in relation to the OP saying his went dull, mine went dull too &... looked like crap. i realize its not supposed to be a top quality looking finish, was only giving a suggestion for how to top coat it to look better.

"I have NEVER had good luck with POR on Any Smooth metal, and I don't recall that on their instructions they have titled instructions for those that don't read instructions"

i dont recall seeing a section called instructions for those that dont read instructions on my can or on their separate full instructions. the instructions i copy & pasted above are from the POR website, i agree its not a good idea to use on smooth surfaces, but POR says it is OK when prepped first.

& for the sandblast naysayer, heres more instructions from POR that clearly says sandblasting is a good way to prep the surface before application...

https://static.summitracing.com/glob...ion%20info.pdf

[burd]

I used white on a Balcony rail for a job since it’s so awesome, had it acid dipped, applied it, next year it was all rusty again, and it’s under a huge overhang. I don’t think I’d ever used it again.
Homeowner called me and said WTH.

[MUSLCAH]

POR 15 is too much work.

When I have no choice and want to use a product like that…I use SEM Rust Trap


Just scrape and apply….and it also sticks on clean bare metal with out all the washing and rinsing.

[tjs72lemans]

If you have everything prepped (like sandblasting), I don't know why someone wouldn't just prime and paint for a look they desire. That's my route. If you have rusty areas, I can see using it in those areas. I've used Rust Bullet in the past, with great results, since I've never heard a complaint of it like POR that peels off. I actually brushed the whole bottom side (as well as inside floors) of my 55 Chevy Sedan Delivery about 14 years ago during a frame off resto and left it the silver look. Still looks the same today underneath.

[rohrt]

POR has it place but I agree if you had your SF blasted that is the time to use a good Epoxy and a top coat.

Keep in mind that even a good epoxy isn't UV resistant. Same as POR.

[dhutton]

Originally Posted by rohrt

POR has it place but I agree if you had your SF blasted that is the time to use a good Epoxy and a top coat.

Keep in mind that even a good epoxy isn't UV resistant. Same as POR.

SPI epoxy has a lot of UV protection. No need to topcoat on a subframe etc.

Don

[78w72]

Originally Posted by tjs72lemans

If you have everything prepped (like sandblasting), I don't know why someone wouldn't just prime and paint for a look they desire. That's my route. If you have rusty areas, I can see using it in those areas. I've used Rust Bullet in the past, with great results, since I've never heard a complaint of it like POR that peels off. I actually brushed the whole bottom side (as well as inside floors) of my 55 Chevy Sedan Delivery about 14 years ago during a frame off resto and left it the silver look. Still looks the same today underneath.

Originally Posted by rohrt

POR has it place but I agree if you had your SF blasted that is the time to use a good Epoxy and a top coat.

Keep in mind that even a good epoxy isn't UV resistant. Same as POR.

i agree i should have just primed & painted the frame, but this was my first time doing a frame off resto 13-14 years ago & POR was what local hobbyists said to use, including the rep at the paint supply store, they all said POR was great for that type of thing as well as the instructions on the can indicated that too, so thats what i used. it did apply & stick OK, just didnt like the look of it. ive since done 2 others & have helped with a couple more on friends cars using the rustoleum paint with excellent results. im just a guy on a budget doing this in my garage, i dont have paint guns to use SPI or other products like that.

POR may have its place but after using it on the place it was designed for, a rusty but clean truck frame, it also didnt perform well. now that ive been involved with painting some cars & am friends with a professional body shop owner, he also doesnt like or use POR, if he uses a product like that he swears by eastwoods rust encapsulator.