Por-15 isn't working out for me

[felix_666]

I have used Por-15 on everything but the car, i have followed the instructions down to a T but every time i go near an object to work on (like the rear brake plates) the stuff scratches off pretty easy. I used 3 coats as instructed and everything had been sandblastered and cleaned prior.

What else is better, i just don't want the stuff coming off becasue the metal is bare underneath and will obviously rust pretty easy, and i can't for ever be touching stuff up. What was on there originally??

I figure two pack epoxy should be pretty tough??

cheers

[gerrynj]

I treid using POR-15 years ago - followed the instructions to the word and

it never really worked as advertized (If I remember the surface has tobe damp - could be wrong). It does scratch off pretty easy and in some places would come off in sheets. What HAS worked VERY well is good old Rustoleum. Prep the surface really well, put on a couple of coats of red oxide primer and then follow it up with 3 thin coats of black. I did the clalipers, brake drums and all suspension parts on my car several years ago. Yesterday I powerwashed everything and the calipers/drums/suspension parts still look like they were painted yesterday.

I still have 3 cans of POR15 in my cupboard - probably stay there forever

Gerry

[BillWilliams]

And that is what is good for. It does not adhere well to anything but rust.

[jerry]

i have a similar opinion of POR-15. i think it should be rechristened "POS-15", personally. i think it's too brittle to be of any long-lasting benefit. i have used DuPont epoxy sealer with good results. it is a 2 part epoxy coating that appears to adhere well to cleaned metal. i have components exposed to the Bay Area fog with no discernable degradation, YET (knocking on wood).

i was able to peel the POS-15 from my windshield area with little resistance. that was enough for me. if moisture got under it it could actually exascerbate the problem.

i am also a fan of rubberized undercoating available in spraycans. it stays sufficiently pliable to withstand the inevitable dings and minor expansion/contraction/vibration issues.

btw, a post a couple weeks ago from a fellow FAQ'er lamenting the appearance of rust bubbles after only 1 year from a professional paint job enticed me to inspect my amatuer paint job that is currently outside under cover and tarps and within close proximity to the SF Bay. I am happy to report, no rust bubbles found, YET (again, knocking on wood). i attribute that to cutting out rust spots and s couple applications of epoxy sealer/primer before actual primer and paint.

[jgerry2002]

The wurth equivalent says right on the can to not use on bare metal. Otherwise you have to prime.

I would assume its also written on the side of the POR-15, though I could be wrong.

[boxy02]

Yup, paint over rust. Not bare sandblasted metal or metal that is devoid of all rust. This stuff will work as intended if you just wire brush the flakey rust off and then brush on the POR. It works by sucking out the moisture in the remaining rust and seals the area to prevent exposure to air (which causes the oxidation of metal into ferrous oxide-rust). I used it on my 914 in the floor boards and had no chipping/flaking whatsoever. I intend to use it on my 2002 floor boards, also. Too bad your experience wasn't as successful, it's a good product. FWIW, I didn't use their "metal prep" system or chemicals, just a wire wheel on my drill.

Cheers,

[bevans6]

When I've used POR15 on bare metal, I've abraded it significantly with sandpaper and used the phos. acid prep solution liberally. It's worked well for me so far. I regard it as brushable powder coat. It works really well on rusted metal, of course, again well abraded and treated with phos. acid.

Brian

[GD]

I wonder if the texture of the surface has anything to do with it. I just painted my freshly sand blasted front subframe and suspension arms with POR-15. The surface was bare metal, but very rough from the abrasive. I wiped them down with paint thinner (I think it's Xylol) first. I brushed on the POR-15. There were a couple of drips on the subframe where I was a little sloppy. The paint stuck so well that I had to file the drips down.

[Armond]

I applied this stuff liberally on the fender wells,floor borads and other places. some with rust present and some without. It's been 2 years and it has not peeled....

[H_Krix]

Paint Over Rust is right, they even spec that the metal has to have a tooth to it in order to adhere. When I did my trunk, i sprayed the whole thing down with their "metal ready" prep and it accelerated the rusting process exponentially. The whole trunk was a nice shade of brown by the time I painted over it.

The POR on my car isn't going anywhere, but thats because there was significant scale for it to adhere to:

[Jaycen_PNW2002]

(nt)

[Jaycen_PNW2002]

(nt)

[scestes]

Can I ask what kind of temperatures you guys were using this stuff in? I've not had it peel at all on me.

[H_Krix]

Was about 85 or so, typical Atlanta humidity also, maybe a little moreso, since my car is in an underground garage, though I have a de-humidifier down there for when i'm not working.

[alp]

instead of POR 15 and such I hand painted my Datsun Roadster frame, and will be doing the body soon, with a galvanizing paint. It is 98% zinc and goes on flat with a brush. It dries to a flat grey colour and is coverable with the right type of paint. You have to watch what the paint is thinned with or it may soften the finish. It is used to paint the mouring bouys and steels decks of the local ferries so I doubt a little road grime and water is going to hurt it. It was cheap at $550/gallon. I used two coats on the frame and I used maybe a third.