im thinking of buying some po15 rust stoper.if i put this stuff over rust thats on my truckover the rear wheel well and let it dry then paint over it is it true the rust will never turn into rot or spread?is it even worth buying it?and will paint stick to por 15 once it dries.any info will help thanks

 

POR 15, RsutBullet, Rustoleum, ZeroRust. These are variants on a theme of putting something over rust that will SEAL out moisture and Oxygen (oxidization) from allowing the rust process to continue/get worse. Most/all rely on first treating the rust with a phosphoric Acid solution (POR's is called MEtalReady), which chemically changes the rust to something inert (doesn't change). Then the "paint" is applied over top, sealing it off from further oxidization.
Does it work - basically yes. So long as you can get the application to stay on the rusted area, it should. Some people have complained that this or that coating can come off if chipped or expsoed to salt, etc.
The promise of POR is only valid if it goes onto soemthing it can "bite" to. That's why it's called POR - Paint Over Rust, vs. Paint over stell, or paint or primer. It will stick to the rust and metal that you treated with MetalReady, then washed with a pre-paint solvent (available at any auto supply store).
After you apply it, either you have to topcoat it within a specific window (I think it's 8 hours) before it gets too hard, or you'll just have to sand it with 220-400grit if you wait too long - before priming and painting over it.
Hope that helps!

 

ok so i need pors metal ready also but also paint slovent?not really sure what that is.thanks 4 your help

 

does it matter what color por 15 i use?they have clear black silver and a few others .is one better than the other?im going to paint over it anyway.i thinking black or clear.anyone?

 

so im going to sand the rust off i know i dont have to but im going too.then im going the area with metal ready then the pre-paint solvent.then i let that all dry and put on por 15 let that dry and then paint over it..is this the right way to do it?i just wanna make sure before i start...the only thing i dont understand is what i need the pre-paint solvent for?thanks let me know

 

this may sound dumb but what kinda brush do i use to put this stuff on with?they dont say anything about that.

 

I used a bristle chip brush to put mine on. For what it is worth, I didn't have that good of luck with it. I now use rustoleum for 25% the cost.

 

I've never used POR15 but i have used Rust Bullet. What i have found is that surface prep is the most important thing you can do. Make sure you knock off all of the scale, that's the problem with steel, the scale flakes off and it allows for rust to continue, Aluminum doesn't work that way that's why it does not rust. As it oxidizes it seals itself.

Any way, follow the directions to a tee and do everything twice. Meaning go over the rust twice to get as much of it as you can, use the acid etch correctly, meaning don't let it dry. Let it do it's work and then wipe it off. Use a wax/grease remover, pre paint solvent, go over ever inch of the area using clean towel until you can wipe the area and still get a clean rag. then you're ready.

I prep'd the underside of my cab and bed for ~2 weeks before i started painting.

Good luck, post some pics.

 

I tried Rust bullet for the first time and I wouldn't recomment its use to my worst enemy. I had nothing but trouble with it lifting after top coating. It seemed to dry way faster than POR-15. Just not as user freindly.

 

OK, to answer your questions:
1. By Solvent I meant "Pre-Paint" wipe aka "wax & grease remover". It's a light solvent that removes any wax&grease and contaminents that are bad for paint. As Duke said, use it liberally - wipe it on and dry it off before it dries. Read directions.
2. Doesn't matter what color you use really because you'll primer it before topcoating.
3. You DO need to get any loose/flaky rust off!
4. Use those 99Cent disposable brushes - and wear rubber gloves - it doesn't come off your skin for weeks.
As per the other comments - people have differnt views of POR, RustBullet, Zero Rust, Rustoleum. The real key is to FOLLOW THE DIRECTIONS. Some bond best to ROUGH surfaces (POR), some to properly sanded areas (ZeroRust). Remember: the Phosphoric Acid converts the old rust to the inert form called Magnetite. The paint stops further rust by inhibiting oxidization.

 

Sorry to hear that Bruce, you're the first person i've heard of that didn't think it was great. What happened?

 

Pretty much tried them all, as noted, follow directions and prep is most important. So far seems, in my case, the POR 15 has held up the best. I applied with a spray gun and pleased with results. Also, suggest purchasing container of their Solvent, if the paint is allowed to set for more than a few minutes it will remain until it wears off. It also is good for cleanup and to dilute mixture if necessary.

Last year tried the Rustbullet and applied with spray gun. I have the parts stored and have not had the opportunity to check them out so verdict is still out.

Not an authority, found many of the body repair shops used a good epoxy primer and paint manufacturer and stick with the same brand that way there would be no issues when it came to applying the top coat. Understand quality epoxy products have rust prevent, and incapsulator chemicals included in the mixture. With respect to fender wells don't imagine it would be an issue. Anyhow, had an urge to chime-in and add my $.02.

 

I could be wrong, but don't those spots always rust from the inside out? Dirt builds up, collects moisture, steel rusts... when the paint starts to bubble, that means it's rusted all the way through the steel. I'd want to sandblast down to bare metal from the underside, treat with phosphoric acid solution to get the last traces of rust, then fill and seal with something like POR15 or "marine" body filler. Judging by some patches I did on an inner fender as an experiment, that can result in a near-permanent fix. Removing all traces of rust is probably not essential, as long as all the metal and remaining rust is properly sealed... rust won't grow and spread without moisture and air.

 

Get yourself some stuff called Rust-Mort. It kills the rust.

Converts rust to black or grayish, hard, insoluble, protective coating.

 

I can't help but wonder ....

If it rusted after it was painted ,(in ideal conditions) ,,what the heck is going to keep it from rusting ,after the rust has taken hold ..

Even chrome isn't stronger tan rust ...

Converters such as POR ,,are mosty a controlled oxidization process ,, similar to gun blueing