Topic: POR 15 products

[cobrajetchris]

I would caution the use of the product POR 15, this product is supposed to be able to paint over rust or properly treated clean metal like sand blasted or metal prepped. I would never paint over rust as it just don't work, however I was told it was a good product to use inside doors, qtrs. fenders etc.. I went by all the directions and did the inside of my doors and it's coming off in sheets and the car has not even hit the road yet. I have to blame myself for this one as I broke my golden rule that any primer or paint product that is not catalyzed is junk and this is a perfect example. I should have used epoxy primer inside the doors, as that stuff will not come off. I spilled some POR 15 and epoxy primer on my dirty garage floor and the POR 15 came off easy with a putty knife and the epoxy won't budge. Anybody else have a similar experience to share? 

[Heap64]

I know I used it on a couple projects a few years back with mixed results.  On the rough stuff it seemed to do ok, but on the smooth slick stuff it didn't bite and could come off like you mentioned.  On my current project I used a product called Master Series and so far it seems to work much more like traditional epoxy primer.  I have heard some people give it really good testimonials so I decided to give it a try.

[macdude67]

I have also found that POR claims for usage are far more broader than what actually works. POR has some great uses but I find that it should never be used on new steel no mater how it is prepped or pretreated. I had it come off of new floor pans that I installed and cleaned and ground with an 80 pad on a rt angle grinder. I ground the panels as that POR requires "tooth" as the say for bonding to the surface. But on the same car I installed some rusty as in surface rusted new toe boards that I had in storage for a few years and the POR stuck like concrete. I also used it on a rear end housing that was coarsely sandblasted and it to hasn't had the first problem.

[yelostang]

When Por first came out, they were explicit in saying it was designed to stick to "tight rust" ie heavy rust that has been wired brushed etc to remove any loose particles. Initially, they also mentioned using it on clean metal and said it should be scuffed well with 40 GRIT!!. But as it's popularity increased, seems as though the mfr became less explicit in  defining it's usage. But..... if Por is used on smooth surfaces, with a mild sanding with less than 40 grit, it will peel. Have been hearing these horror stories for a few years, but people staunchly defend it. Why then, did the mfr. of Por, years after it's introduction, finally come out with a product called metal ready or tie coat, something like that. The new product IS to provide a base with good metal adherence and so that Por will stick.
So..........the question is: Why use it in the first place!! Used to use the stinky fish oil rusty metal Rustoleum with better results. There are many other products out there. But.......for vintage Mustang restoration, REMOVING the rust in it's entirety seems like the best approach. New metal is available and there are many techniques  for COMPLETE rust removal. Many use a product called Zero Rust and seldom here any negative comments on it. Also, Eastwood has a product, also.


Do not think that epoxy primer is a panacea for stopping rust by using it over same! It sure is good, though, for application on clean metal or correctly sanded metal and it will stop rust from coming back AFTER the ugh! brown stuff is removed.

[BuckeyeDemon]

i also don't understand why so many people are using POR when they refinish their cars.  it seems as though if they are going thru all that effort then just clean the metal properly and spray some epoxy, especially in visible areas.  i feel like i'm either ignored or slammed whenever i mention it.

my father used it on an old school bell.  it was terribly rusty less than a year later.  that was enough evidence to me that you really need to get the metal clean to stop rust or at least slow it down for metal exposed to the environments.

[428scj]

I used it on my old 71 Bronco on the floors inside.It hasnt peeled ,blistered or lifted anywhere.I did spray the rusty spots with the metal ready first and after it dried spayed it down.Its some of the stongest paint Ive ever used.I have heard about the peeling on new metal also.

[rmaginnis]

I have a can of it and it states that it is not intended for use on new metal. It chemically reacts and bonds to the iron oxide layers. Without the rust/oxide it won't be effective. No question that excising the rust is the best thing to do. I use it in between seams and spot welded joints that aren't bad enough to warrant panel separation and re-spot welding. I've had no issues with it so far.
Rick

[cobrajetchris]

I would do a GOOGLE search on "POR 15 problems" before anyone uses it. I would not put this stuff on my lawn mower, use professional catalyzed automotive primers and paints an you get professional results. Remember rust never sleeps and covering it up doesn't mean it's gone.

[KStang65]

Do a Google search for Epoxy Primer Problems before anyone uses it.

I've used POR 15 in a few areas with seasoned metal such as on the outer wheel well before installing the quarter panel.  A month or so later, I tried to wire wheel off the POR 15 where I was going to be welding.  Man that POR 15 was almost impossible to get off.  The places where I sprayed epoxy primer came off like nothing.

Also, I don't care what they say.  Applying body filler over epoxy primer is not good.  It'll pop off like nothing if you have to lightly take a hammer to the sheetmetal.  I did some searching and found a good test someone did with epoxy primer and body filler which confirmed my experience.

[PetesPonies]

I have been using Master Series in my RUSToration business for many many years now. I have not had a single failure and give my word on how it works for me. I have seen POR failures and would avoid it. Unlike POR, Master Series is a primer and is intended to be topcoated. It works on any surface, rusty or clean. It is the ONLY material I use in such situations.