I bought some POR15 a while back to try it out and I am very unimpressed right now. Maybe I am doing something wrong? I tried it out on the nine inch Ford axle I am prepping for my truck.
I started out by wire-brushing the housing, then followed with POR 15 Marine Clean and pressure-washed. Then I treated it with POR 15 Metal Ready. After it dried I brushed on the POR 15. It flowed out pretty well and the next morning it looked pretty good.
About a week later, I seen what looked like small pinholes with exposed rust on the axle tubes. Suspecting the coating was not bonded well, I took a razor blade to the spring pads and the POR 15 peeled right off like old house paint. Now for a product that you are supposed to able to hammer, bend etc it should have been more difficult to remove. After that I have tried to peel it off of several other spots and it peeled right off.
I double and triple checked the directions and even checked again after this problem came up. I was wondering if anyone has had a similar experience or if there is something I missed. I bought Chassis Saver for my frame but it is supposed to be similar. The thought of having the same problem on my frame is on my mind.......

 

My dad has a 1999 peterbilt that had rust issues with the frame on the rear and we scraped cleaned ground on and went through it until it was all bare metal. washed it used metal ready for 30 min washed again like he said and that was 6 months ago it laid out good and he even painted rustoleum over it because it will get chalky now it is bubbling underneath like wildfire we were some mad people. all that work for nothing. That stuff sucks!

 

POR-15 doesn't like to stick to nice clean metal. It needs a texture like solid rust or blasted metal to adhere to. Could the places it's peeling off of be too clean? I know I experimented on metal I ground clean with an angle grinder and it seemed like POR-15 just skinned over it, didn't adhere at all.

 

I've never used their prep products, but I have used their rust coatings. As I recall, it says clearly on the can to use only on rusty metal, as it will only stick to rust (and your skin) not to clean bare or prepared metal. It also says it does not have any UV screening protection and is not to be used on exposed surfaces without topcoating. There are also very explicit directions on how to make the topcoat stick, since once the stuff dries, it is too hard to sand or for other coatings to stick to POR. I've heard of several people with stoires of failure, but figured it was more operator error than product failure. But I haven't tracked it's performance for years, either.

 

The housing was still rusty. I only used the wire brush to knock off the loose stuff. I think paint would have adhered just fine. I chose POR 15 for the advertised scratch and chip resistance.

 

I did some research on rust encapsulators, which POR-15 and the other are, and found a product for half the price that I'm fairly certain will work the same. For my '37 Buick I'm going to blast the frame and body and coat the non exposed surfaces with PPG epoxy mastic. It's made to paint directly over solid rusty metal or blasted metal, just like the encapsulators. It is used to coat rusty outdoor structures like water tanks and railings. It is not UV resistant, just like the rust encapsulators but can be top coated within 30 days, after 30 days it has to be scuffed up a little. POR-15 can only be top coated with more of POR-15's products or you can prime over it with normal primer if you do it just as the POR-15 product starts to turn tacky. I sprayed epoxy primer on tacky POR-15 and it reacted badly and lifted the POR-15.

I've tested the epoxy mastic on the rusty frame of my Buick by wire brushing an area with a hand wire brush and applying it three different ways on both solid rust and on blasted metal. I first applied it as a 1 to 1 mix to the rusty frame and a piece of blasted metal. I also thinned it with xylene, as per the PPG phone rep's suggestion. I also thinned it with lacquer thinner. Both thinner cans said they are epoxy thinners, xylene being a slow reducer and laquer thinner being a faster reducer. The 1 to 1 mixture took about three days to dry hard but I only had my shop up to 65°, the can listed the pot life at 4 hour @ 70° so maybe if I had the shop warmer it would have a better chemical reaction and dried faster. The xylene mixture took about five days to harden but the lacquer thinner mixture took as long to dry as the 1 to 1 mix with a very slight duller finish. I mixed enough thinner in both batches to match the consistency of POR-15.

The major advantage is price, a gallon of POR-15 costs about $150, my epoxy mastic cost $100 for two gallons and I can thin it enough with the lacquer thinner to get about 2 ½. gallons. The base paint out of the can has the consistency of latex paint and the activator has the consistency of peanut butter but when mixed together the chemical reaction makes the mixture the consistency of an oil based enamel. Another plus is you can mix the amount you need and the rest won't harden until you mix it together. POR-15 reacts with the moisture in the air and starts to harden as soon as you open the can. You have to line the top of the can of POR-15 with plastic wrap to help retard the drying of the portion of the product that remains in the can and to prevent the lid from cementing to the can. If you store a sealed but once opened can of POR-15 the entire can will eventually harden in a rather short period of time.

The draw backs are the longer drying time and you have to buy the epoxy product in two one gallon cans, it might be too much if you're going to do a small project but you could always go in with another person and share the cost.

 

Greta info BobJ ! thanks for typing all that up.

I will need a lot of material when I finally get around to doing my F-6 ( the back half of everything has got some great surface rust to adhere to, that mastic stuff you describe will work well on unprepped surface rust???

I plan on just using my father inlaws pressure washer and just power washing everything off really well, maybe a few locations will need a nice hot sudsy bucket of Dawn dish soap and scrubber but otherwise I don't want to put much more effort into it than that.

Josh

 

I was planning on hitting the frame with a cup brush on my angle grinder then scrubbing it clean before applying Chassis Saver. I have heard of people doing the same thing before. Should I have it sand-blasted?

 

I have been very satisfied with the POR products and using them since 1999. My first gallon of POR-15 didnt get used for a couple of years. In fear of a short life, I opted to punch a nail hole in top and on top side of the gallon can. This way there was never a chance of moisture getting in the can. I also stored the gallon in the refrigerator when not in use. I am sure you wont believe this can is still in the fridge and just about empty. Thats been 11 years since I first purchased it. I have used plenty of the different colors and the other products they offer. I never used the Metal Ready or Marine Clean. Just always degreased very well and sandblasted to clean metal. Way too many things that can cause the coating not to adhere well any other way. I figured if you can rub your finger on a piece of rusty metal and it gets dirty, then no way any coating is going to adhere permenantly. Sorry for anyone that has not had very good luck with the product line. I know they try to make it user friendly as possible. But this leaves way too much chances for human error. When applied correctly, it is closer to a powder coated finish than any other painted products offered. But this is just my opinion based on personal experience with the stuff.

 

The best thing to do is blast the metal before applying. I plan to blast before applying but a good wire brushing should also work as long as there isn't any scale rust left, only good, solid rusty metal. I am sure the application of anything is best when you have clean, blasted metal.

I did the refrigerator storage, made everthing in the frig taste like POR-15. Fortunately, I I stored it in my shop frig but I had an employee at the time and he wasn't too happy. I would have faced some serious action if I used the home frig

 

I used RUST BULLET on the frame of my 51 and it worked reeeaaally well. I actually hit it with a hammer and it didnt chip, pretty durable stuff....its just not cheap! well to me it isn't cheap, like 100 bucks for a gallon, but it covers quite a bit of square feet.

 

I've been using POR for about 7 years and have never had a problem like you described. I painted the entire frame, front suspension, rear suspension, springs, inside floor and underneath and all I did was clean off the metal with a wire brush. The only peeling I have seen is when I tried to use it on exhaust manifolds which I suspected would not work. I never used any kind of metal prep...POR or otherwise.

Perhaps you just got a bad can? I never have but I suppose it's possible.

 

My powder coater didn't want to do my leaf springs, so I had to choose another option. I had mine sandblasted and I sprayed Chassis Saver. Laid down really nice, and I'm no painter. Seems to be super durable and didn't like to come off my hands or out of my paint gun!

The resto shop I use to work at used chassis saver all the time, and they didn't always sandblast, just grinder and cup wheel.

 

I used POR-15 on a bunch of my stuff and have had mixed results. It's done great on my frame, which was probably the least prep as far as getting rid of surface rust, etc before applying it. I also sprayed it on that, which I wouldn't recommend to anyone unless they want to feel like crap for a week afterwards. On some other front suspension parts I've noticed its been peeling - I brushed all those. These are cast parts, thus more porous, which I would have expected to hold paint better.

Overall, I agree with the notion that it does not stick to clean, extensively prepped metal very well. Looking back, for as much prep work I put into alot of my parts I would have been better off putting a traditional paint coating on it.

But, for those people trying to keep their cans from hardening, I put mine in a mason jar with a screw on lid. Before closing the lid I spray a bunch of argon mix from the welder into the jar to purge all the air out. It works great. Same goes for most paint hardeners/catalysts that typically have a short shelf life.

 

I have used POR on several jobs and never had it peel like you mentioned...maybe the surface was contaminated with oil or grease?