POR 15 fail

[RabbitHoleSS]

You have to apply an acid etch before painting clean metal with por 15, something like ospho will work.
Epoxy primer with a topcoat will last forever. I used kbs coating system(not 2k), with rustoleum as a topcoat. I can't complain about it, it's hard to remove and was easy to apply, but if I were to do it again I'd use epoxy primer and a cheap topcoat that I could easily repair.
Surface preparation is all that matters When you do it this time. You need clean metal. No dirt,wax,grease,road grime etc. Plus 80 grit DA scratches. Or by hand....
Also, just an observation but those parts look really shiny in the pics. I'd make sure everything has 80grit DA scratches so whatever paint you use has a good tooth to bite into. The high speed from grinders, rolocs, etc kind of polish the metal imo. Rktpwrd am I wrong, I dont wanna give him crap advice 😆?
Wire wheel most definitely won't work, it really polishes the metal.

 

[Hurricane77]

You have to apply an acid etch before painting clean metal with por 15, something like ospho will work.
Epoxy primer with a topcoat will last forever. I used kbs coating system(not 2k), with rustoleum as a topcoat. I can't complain about it, it's hard to remove and was easy to apply, but if I were to do it again I'd use epoxy primer and a cheap topcoat that I could easily repair.
Surface preparation is all that matters When you do it this time. You need clean metal. No dirt,wax,grease,road grime etc. Plus 80 grit DA scratches. Or by hand....
Also, just an observation but those parts look really shiny in the pics. I'd make sure everything has 80grit DA scratches so whatever paint you use has a good tooth to bite into. The high speed from grinders, rolocs, etc kind of polish the metal imo. Rktpwrd am I wrong, I dont wanna give him crap advice 😆?
Wire wheel most definitely won't work, it really polishes the metal.

I also have a theory about these different 'rust encapsulators' etc. The main premise they work on is to completely seal off the rust from the elements and air to prevent further oxidation. No more oxygen = no more oxidation right?

Well, POR-15 and similar require a rough surface to make a mechanical bond to the metal. Without it, it doesn't bond properly.

But a good DTM epoxy primer would do exactly the same thing, but better. Again, those require a proper surface prep and mechanical bond. The SPI stuff I'm using requires a 80 grit sanding prior to application. But the epoxy is going to bond to the clean metal better, will will still seal out the oxygen to prevent further oxidation, the same as POR15 and others.

So I'm with you. Clean out all the rust you can. Epoxy primer and topcoat. No need to mess with these 'magic wand' products

 

[Screwz]

I also have a theory about these different 'rust encapsulators' etc. The main premise they work on is to completely seal off the rust from the elements and air to prevent further oxidation. No more oxygen = no more oxidation right?

Well, POR-15 and similar require a rough surface to make a mechanical bond to the metal. Without it, it doesn't bond properly.

But a good DTM epoxy primer would do exactly the same thing, but better. Again, those require a proper surface prep and mechanical bond. The SPI stuff I'm using requires a 80 grit sanding prior to application. But the epoxy is going to bond to the clean metal better, will will still seal out the oxygen to prevent further oxidation, the same as POR15 and others.

So I'm with you. Clean out all the rust you can. Epoxy primer and topcoat. No need to mess with these 'magic wand' products

At this point I’m just going to clean up as much as I can and Epoxy primer and a topcoat. I really wasn’t planning on this much work . I just wanted to do a quick cleanup and seal it up . This all started because I wanted to replace my gas tank. It has a patch that works but I can’t leave things alone .
time to get a new tank and get this thing back together. I have a few more chassis braces to make and install then put it all back together.

 

[Rktpwrd]

those parts look really shiny in the pics. I'd make sure everything has 80grit DA scratches so whatever paint you use has a good tooth to bite into. The high speed from grinders, rolocs, etc kind of polish the metal imo. @Rktpwrd am I wrong, I dont wanna give him crap advice 😆?

You’re not wrong, spot on in fact. That’s exactly what I’d do too.

 

[Rktpwrd]

Surface preparation is all that matters

This.

 

[rad928music]

I was building a rear shock tower brace and scratched the frame and realized that I will peal off . a few hours later and it’s all gone.View attachment 217877View attachment 217878View attachment 217879View attachment 217880View attachment 217881View attachment 217882View attachment 217883View attachment 217884View attachment 217885View attachment 217886
Im glad I caught it now . i won’t be using POR 15 again .

Your car looks pretty solid underneath.
You could Scuff the BM and Go with some Black Rust-Oleum paint, several Thin Coats.
If you drove your car out here in Minnesota for a day Surface rust would already have formed.

 

[Clone TIE Pilot]

I highly recommend 2k epoxy primer, 2k chassis urethane, then underbody wax.

 

[CopperNick]

POR-15 was always advertised as an "encapsulator", meaning it was meant to cover rust infestations and seal them off from air. Absent the presence of the air, no oxidic reaction will occur and the rust quits expanding its presence.

I've personally had the peeling experience with it but found that moisture had worked its way under the coating for whatever reason and caused the rust to reactivate. i also found that it was important to get all the loose rust or platelet material removed. Pits and pores got left as they need media blasting to really clean out.

As for application, well for frame rails, I like to use a roller and small paint tray for the initial application and then go over it with a brush. Tight areas and nooks/crannies get the brush. You can even use a throwaway spray bomb kit and dilute the stuff with its own solvent.

When I did and documented my S-10 frame last summer, what I did was to get the metal down to bare, hit it with RustMort, went over that to expose any misses, hit it again, then laid on the POR-15 over that. Once it dried, the whole frame got a good coat of Krylon Antirust and then a top coat of Semigloss black to seal it all up.

For those who would consider all this major overkill, yeah, and I live in the Salt Belt so anything that will keep the brine at bay is to be embraced.

And yeah, it does have an operational life, meaning that at some point I will have to inspect it and determine what needs to be taken down and recoated and to what point.




Nick

 

[Ugly1]

POR-15 was always advertised as an "encapsulator", meaning it was meant to cover rust infestations and seal them off from air. Absent the presence of the air, no oxidic reaction will occur and the rust quits expanding its presence.

I've personally had the peeling experience with it but found that moisture had worked its way under the coating for whatever reason and caused the rust to reactivate. i also found that it was important to get all the loose rust or platelet material removed. Pits and pores got left as they need media blasting to really clean out.

As for application, well for frame rails, I like to use a roller and small paint tray for the initial application and then go over it with a brush. Tight areas and nooks/crannies get the brush. You can even use a throwaway spray bomb kit and dilute the stuff with its own solvent.

When I did and documented my S-10 frame last summer, what I did was to get the metal down to bare, hit it with RustMort, went over that to expose any misses, hit it again, then laid on the POR-15 over that. Once it dried, the whole frame got a good coat of Krylon Antirust and then a top coat of Semigloss black to seal it all up.

For those who would consider all this major overkill, yeah, and I live in the Salt Belt so anything that will keep the brine at bay is to be embraced.

And yeah, it does have an operational life, meaning that at some point I will have to inspect it and determine what needs to be taken down and recoated and to what point.




Nick

It is also to be noted and many have stated it as well, IV rays do deteriorate POR 15 if it is not covered by another product. Your “over kill” definitely is not a bad thing!

 

[UC645]

POR-15 was always advertised as an "encapsulator", meaning it was meant to cover rust infestations and seal them off from air. Absent the presence of the air, no oxidic reaction will occur and the rust quits expanding its presence.

I've personally had the peeling experience with it but found that moisture had worked its way under the coating for whatever reason and caused the rust to reactivate. i also found that it was important to get all the loose rust or platelet material removed. Pits and pores got left as they need media blasting to really clean out.

As for application, well for frame rails, I like to use a roller and small paint tray for the initial application and then go over it with a brush. Tight areas and nooks/crannies get the brush. You can even use a throwaway spray bomb kit and dilute the stuff with its own solvent.

When I did and documented my S-10 frame last summer, what I did was to get the metal down to bare, hit it with RustMort, went over that to expose any misses, hit it again, then laid on the POR-15 over that. Once it dried, the whole frame got a good coat of Krylon Antirust and then a top coat of Semigloss black to seal it all up.

For those who would consider all this major overkill, yeah, and I live in the Salt Belt so anything that will keep the brine at bay is to be embraced.

And yeah, it does have an operational life, meaning that at some point I will have to inspect it and determine what needs to be taken down and recoated and to what point.




Nick

I’ve seen this theorized in a couple of other boards, but the issue with POR 15 and other moisture cured urethanes is that they cure so hard, they’re almost ceramic-like in nature.
Any paint will crack and fall apart but POR kind of snaps when you try to bend it, again like any other paint, but has far less give to it before it does.
So when it’s on a surface that can flex, like a car frame or sheet metal, and it has enough adhesion, it cracks but stayed adhered, leaving gaps in the finish that let moisture in but then traps it, letting the oxidation feed on it or starting new areas of rust.

Your idea of overkill, and Wraith’s, should be standard procedure with this stuff, Nick.