Even though they don't recommend it, I shake the bejesus out of it, let sit for a minute or two for the bubbles to rise, then remove the screws and pour. Way back when I first started using POR the distributor told me this was the best way to use a partial can. When the can is full is the hardest but once down a ways it shakes up pretty easy. Been using it this way since then and it seems to work . . .
POR is cured by moisture. One drop of sweat in the can will ruin the whole can overnight. If this happens you need to use as much as you can because tomorrow its ruined.
I have a trailer we built over 30 years ago --I OSPHOed the new metal and didn't really clean the Ospho well and painted it with black Rustoleum--the only places that there is even any surface rust are where I scratched through the paint to bare metal and I lived mostly in Galveston county which is the rust capital of the world
I have used the screws in the top, put it in the frig, and have good success. You do have to let the bubbles settle down after shaking. One point: POR can be sprayed but is VERY toxic in that form. Make sure you have good ventilation and a very good respirator. I have used it on several floors where blasting would have been a mess. Since it goes on with a brush, you don't have to worry about overspray. A few more points: Use gloves, POR will not come off. Drops will come off cement with a putty knife. Throw the brush away when done. It is not worth cleaning so don't get an expensive brush. Foam brushes work too but don't last very long on rough surfaces. Don't use heavy coats as it will run. We used 2 coats. The first one in flat black, the next one in gloss black. It is easier to see where you have painted so you don't miss a spot. I put what I am going to use in plastic dish, then seal the can. Just like regular paint, preparation is very important.
I sandblasted and POR-15'd the entire bottom of my '51 Ford on 1988. Last summer, I had to work on the rear springs, and everything still looked great (but a little dirty). It doesn't stand up to UV real well, but for the underneath of a car that spends it's inactive time in a garage, it can't be beat, IMHO.
I have used a product called Extend for over 30 years. it is now made by Loctite. It is a rust convertor and No the rust is Not still there after you treat with it. The rough surface may be, but the "rust" is gone, neutralized. I coated the floor pans of a 66 Mustang in 1983 with it, inside and out. If you pull back the carpet, it still looks like the same black surface that it did when it originally dried 31 years ago. If you break through the surface of the coating, it can start rusting again as you now have bare metal, but if it is coated properly it works very well.
pressure wash and clean off the undercarriage as good as possible. then hit the bottom with a eust converter, typically phosphoric acid based. pressure wash again then apply undercoating with a schutz gun, not the spray on crap. ideally would be an epoxy primer first depending on how clean you can get it underneath.
I still have a can of "Corroless" that I never opend. May try that some day. I think it's the same a POR 15 but was sold by Eastwood.
I have partially used cans of POR that are many years old. I never open the cans. I punch a hole in the center of the lid, drip out what I need, and put masking tape over the hole. Repunch next time, and more tape.
Muriatic Acid will stop rust. You need to wash it off and neutralize it after use. Then you could use EPOXY PRIMER to seal it from everything. I use SPI Epoxy on bare metal, I always blast off the rust or repair the area. There really is no excuse for leaving rust on the metal anywhere.
I am not a proponent of using POR type products except in the case of inaccessibility in void areas where you can't get to for proper media blasting or abrading for using epoxy primer. So this would limit their use to areas that are not exposed or areas that will not get top coated. Even then there is no guarantee for success as these type products promote shortcuts. To elaborate, you can go on any automotive forum and see all the proponents of using such products. Even the guy who still has a project in the garage that has had no exposure to the outside elements since application is touting the benefits of these paints. It all boils down to human nature. We are looking for the easy way out, whatever gets the job done quicker. Whether it be someone's lack of welding capability to weld in new metal, or not wanting to media blast/properly abrade for a better coating of epoxy primer, these POR type products and rust conversion products promote shortcuts. I challenge you to go on any automotive forum and research the various threads on these products, and practically everyone is singing their praises. Rarely will you see anyone adding any cautionary notes about rust converters having reaction issues with some epoxy primers that will cause delamination. Rarely will you see someone mention that POR does not promote good adhesion for a top coat. They are so overwhelmed by all the work they have saved in media blasting, or panel replacement, that these issues have never entered the picture. Anyone who dares breathe a word to the contrary, obviously has done something wrong.... and doesn't know what they are doing.. But I do know that epoxy primers are designed to be used as a substrate to practically any other automotive paint product out there. POR, not so much. Likely the largest single cost associated with any restoration will be the paint finish. So why risk paint adhesion issues with these short cut products? In my case, that would involve rework that comes out of my pocket. So I tend to lean towards using products designed for a topcoat, epoxy primer. When I did the repairs on the wagon tailgate, I did have the inner gate and skin separated, where it made more sense to media blast/abrade the panels separately, epoxy prime, and then assemble. See here: http://www.jalopyjournal.com/forum/showthread.php?t=550803 The only additional thing I'll also do there is to mix up more epoxy, dump inside, and slosh around the seam to seal it out for good. If you look at some of the damage inside the original tailgate skin you'll also see some deep pits nearby the ones that have broken through into pinholes. Where POR may be an option to protect this inaccessible area (if we hadn't separated the parts), it will hardly stop these deeply pitted areas from continuing to rust through. This is why many of your top restorers will remove door skins, hood skins, etc. to verify/remove any pitting damage prior to painting, and then re-assemble. When you're paying upwards of 20K for a paint job, you want it to last and you do what it takes to make sure that it will last. Guarantee that none of these guys use POR. So while I do think there are places where it makes sense these products can be used, they are far from fail safe and even farther from the quality of repair that fresh sheet metal and epoxy primer can give. So someone needs to have some common sense when an area shows rust issues to exist, one pin hole coming through is seldom alone. With all of these type products, their biggest liability is they promote shortcuts, which in many cases involves a project in sore need of fresh sheet metal.
To clarify my position, while I have used POR-15 with great success on chassis and mechanical parts, I would never even consider it on any surface intended for a final finish coat.
Tubman, my point exactly. In many cases in threads like this, the OP never elaborates too well as to what is being done, and the response posts typically give a blanket seal of approval, without discussing any of the shortfalls with said product. A nice recipe for failure. Thanks for clarifying..
As to the Muriatic instead of Phosphoric acid approach I suggest this thread as a warning...http://www.jalopyjournal.com/forum/showthread.php?t=813794&highlight=muriatic
Ppg makes a 2 component idustrial product that is refered to as an epoxy mastic. It is made for structural iron and bridges where removing 100% of the rust is not always possible. It will encapsulate, and convert rust. They claim it can be applied directly to rust scale, I have had success using it in industrial applications, but still recomend removing as much rust as possible. Posted using the Full Custom H.A.M.B. App!
Yes I want to go with the 68 mustang tank. I like the low profile. Only downfall, is its capacity is only 16 gallons. May have to modify it or build a custom tank ??
I use a lot of POR-15 and you can ruin a whole can if you don't seal it well as many have already stated. I tired the screw trick but I like to stir and use the can to paint out of so I don't ruin all of my mixing cups so I pull the lid off. I re-seal the can when done with a sandwich bag (both layers), just lay it on top of the can and put the lid back on. The lid doesn't always go back on all the way so I set my "Oldsmobile hammer" (10 pounder) on top to hold the lid down until the plastic seals. Next time I use it I remove the lid and cut the plastic off. Works every time and stay useable for months. Tried a lot of rust converters and sealants but really like the POR product and it works best applied directly over the top of rust and scale so it is good for lazy people. Oh, don't get it on your skin unless you want your body sealed as well. One more warning, I bought the reducer and sprayed it in my primer gun once...once. I miss that gun.
I have used this rust converter for a couple of years now, I leave a partial bottle on the shelf in a unheated garage all winter, still works the same as when first opened. I get it at O'Reilly auto parts for around $60.00 a quart, a little pricey, but does what it says. It's made by 3M.
Eastwood makes a product that dissolves rust (Oxisolv), great for getting into seams and other places. I had pretty good luck with that stuff.
Responding regarding ospho Do read your data sheets on your paint products your applying OVER the ospho. Some products have an "allergic" reaction to it so check your sheets or call manufacturer. I had an episode with Valspar. I use it still when I prep panels to bare steel and are in waiting to be sprayed. Keeps them from flash rusting etc. To reactavate I wipe panel WITH Ospho then wash with dawn dish soap and water. Thoroughly dry and heat gun the seams a bit to get good and dry. I then will run a sander around it one last quick time to shine a bit then wipe down with wax/ grease. You are then ready for any product. I have became gun shy to applying anything straight to ospho. Just my experience
The '70 tank can be had in 22-gallons. It is the same from the lip-down. The extra capacity is above the lip, inside the trunk. 1968: 1970: Dimensions are otherwise the same.
Buy the smallest size POR15 can possible. I bought a quart to do some undercoating here and there on my Ford. It goes on thin and a little does a lot. First off, the lid was toast in getting it off. So I transferred the bulk to an old spaghetti sauce jar and it sealed up tight. The rest went in a plastic butter container. I went to use it and it had skinned over... stuck my thumb in it.. mistake. I would have been far better off with their smallest can, chuck it when I was done.
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