Por-15 ot

[Don Coatney]

Can someone explain to me why POR-15 or an equally expensive substitute is so much better than standard primer paint? Why is it worth the extra money? Many places on my car (such as under the rear seat) still have the factory coating in place and working after 62 years. Had the factory used POR-15 would it look good after 100 years? I personally dont think I will be driving my car 62 or 100 years from now. Why should I spend my retirement funds on POR-15?

[BeBop138]

Don, I use it for rust prevention---after the rust has started. Very thin paint and goes in the hard to get places. I use Bill Hirsch rust paint and have been very happy with it. Great for frames,air cleaners,floors and all the spots you want to stop rust..........to each his own........Lee:D

[Joe Flanagan]

You should spend your retirement money on POR-15 because that's what the POR-15 people want you to do.

[greg g]

because after you put it on your rusty frame, and the frame continues to rust beneath POR's surface, when it deteriorates completely the hard shell of the coating creates the illusion of strength.

[BobT-47P15]

If you buy in huge quantities, it could put you in the PORhouse.

[Big_John]

In answer to the question, POR-15 isn't really used as a paint primer. It is a rust encapsulating paint that is used to stop rust by preventing moisture and oxygen from contacting the steel. It adheres best to already heavily rusted steel and not as well to clean steel. Its also not good to expose to UV light (as in the sunlight) as that will cause the POR-15 coating to breakdown.

So... in a nutshell, no, POR-15 would not be the best primer.

The paint/primer on your Plymouth is most likely lacquer. Good, fast drying, and easy to apply. It also will last a long time (like under your seat) if its not exposed to the weather. It also chips and scratches easier then enamel. Lacquer primer is also porous. Ever see a lacquer primed car that's been left outside for a while? The surface rusts from the oxygen and moisture.

Fast forward to the present... new primers are epoxy or urethane based. They adhere better and more importantly seal the surface better. They also allow for the newer and superior paints in use today.

So... is the new paint better? Yes, most definately. Back when the cars were new, it wasn't unusual to have them painted after 5 or 6 years. I remember my Dad's '57 Windsor being repainted in 1961. Now its unheard of to have to have a car repainted for any reason except accident damage. Cars go to the crusher with 200k miles and the original paint.

[55 Fargo]

Tim Adams recipe for inner panels, floors, frames etc, sandblast if possible, or sand and wire brush, acid treat, and primer with Rustoleum rusty metal primer, paint with Rustoleum oil based paint, or use rubberized undercoating end of story.

POR 15 is another high priced encapsulator, paint over solid rust, not flaky loose scaly rust.

The truth be known, if you clean up rusty metal, and paint all sides, and let cure, all is well.

No air ( o2), no moisture, no rust process, or at least it is delayed, until some void will allow air, water, salt to penetrate to start the corrosion process.

I have painted some itmes, that still had solid rust, and it is still holding up very well, as my car is driven in summer only, and not in sloppy,slushy, salty, winter weather.

I would use Tim Adams recipe, or a paint called Zero Rust is pretty good, and 1/2 the price of POR 15. POR 15, can delaminate too, Rustoleum/Tremclad, sticks like $hit to a blanket, once cure, the trick is to get have good prep, and good coverage on all sides, so as not to allow penetration of salt, crud, rust and moisture to attack.

How does that sound Don........

[55 Fargo]

In answer to the question, POR-15 isn't really used as a paint primer. It is a rust encapsulating paint that is used to stop rust by preventing moisture and oxygen from contacting the steel. It adheres best to already heavily rusted steel and not as well to clean steel. Its also not good to expose to UV light (as in the sunlight) as that will cause the POR-15 coating to breakdown.

So... in a nutshell, no, POR-15 would not be the best primer.

The paint/primer on your Plymouth is most likely lacquer. Good, fast drying, and easy to apply. It also will last a long time (like under your seat) if its not exposed to the weather. It also chips and scratches easier then enamel. Lacquer primer is also porous. Ever see a lacquer primed car that's been left outside for a while? The surface rusts from the oxygen and moisture.

Fast forward to the present... new primers are epoxy or urethane based. They adhere better and more importantly seal the surface better. They also allow for the newer and superior paints in use today.

So... is the new paint better? Yes, most definately. Back when the cars were new, it wasn't unusual to have them painted after 5 or 6 years. I remember my Dad's '57 Windsor being repainted in 1961. Now its unheard of to have to have a car repainted for any reason except accident damage. Cars go to the crusher with 200k miles and the original paint.

True, on POR 15 and it's intended use and performance.

I think Don's car is acrylic enamel, not lacquer, it's paint job is not all that old.

I have used rusty metal primer on a bare steel substrate, and, have done body work over it, used lacquer primer over it, and have used 2 k urethane primer over it.

Metal primed with rusty metal primer, shot on in say 2 to 3 coats, seals very well, maybe not like 2 k epoxy, but still very well.

I believe Mopars of the 40s were painted from the factory with synthetic (alkyd) enamel, which was baked on, repairs were quite often either made with the same enamel or for speed possibly lacquer based products.

GM used lacquer, and possibly Furd.......

[55 Fargo]

Can someone explain to me why POR-15 or an equally expensive substitute is so much better than standard primer paint? Why is it worth the extra money? Many places on my car (such as under the rear seat) still have the factory coating in place and working after 62 years. Had the factory used POR-15 would it look good after 100 years? I personally dont think I will be driving my car 62 or 100 years from now. Why should I spend my retirement funds on POR-15?

I would not disturb any firm intact undercoating on your car, unless a repair must be done, and that is not your case.

You can paint over it with Rustoleum rust paint if you want.

I am sure if your car is kept dry, or not allowed to rot to the grass someday, those floors will be in fine shape many years from now.

Save your money for more important things like doo-dads, or high perf upgrades for your car.......

[Tom Skinner]

I'm with Don, that stuff is expensive and just hides what needs to be fixed properly. I would weld in new and paint it.

There is a couple of old guys in Booton NJ, they are the Kanter Brothers,

they have a saying it goes like this "Do it once and do it right".

POR - to me - will just will hide stuff/rust.

That causes more work later on down the road.

Just MHO. Everyone has got one.

This is not to offend people whom have used this product and like it.

Even the Kanters sell POR. I just avoid it as a personal note.

Tom

Huntersville, NC

[PatS....]

I have used POR15 in two places, on the back of the rear bumper on my Ford Econoline.

Now the crap that is flung up there doesn't stick and it may not rust like the first one did.

And, on the underside of my old lawn mower. I read that POR15 would prevent the grass from gumming up the works under there so I don't have to clean it.

So far so good. Grass doesn't stick anymore and I don't have to clean it.

I haven't used it on an old car and can't see a time when I would.

[55 Fargo]

I'm with Don, that stuff is expensive and just hides what needs to be fixed properly. I would weld in new and paint it.

There is a couple of old guys in Booton NJ, they are the Kanter Brothers,

they have a saying it goes like this "Do it once and do it right".

POR - to me - will just will hide stuff/rust.

That causes more work later on down the road.

Just MHO. Everyone has got one.

This is not to offend people whom have used this product and like it.

Even the Kanters sell POR. I just avoid it as a personal note.

Tom

Huntersville, NC

I think the intended use is for metal that is rusty, not totally corroded with holes.

Dan and Fred Kanter, sell you once, buy forever, just kiddin, there slogan is wise.

If you need patch panels then use em, weld them in.

But on frames solid floors, heavy metal objects, you obviuosly don't need to be welding in patches.

The POR 15, even plain old rusto paint, likes a lightly corroded surface, rather than a slick new metal.

Lot's of people use rust paints on less than quailty substrates, were not talkng about filling holes with Bondo, and then painting over....

[Big_John]

I've used it a couple times on some old Jeeps that needed some "love" to make them a bit more presentable. It worked well for me, but I also tend to follow directions on how to apply stuff like that.

No... its not the "right" way to do it, but it worked for my application.

[Big_John]

True, on POR 15 and it's intended use and performance.

I think Don's car is acrylic enamel, not lacquer, it's paint job is not all that old.

I have used rusty metal primer on a bare steel substrate, and, have done body work over it, used lacquer primer over it, and have used 2 k urethane primer over it.

Metal primed with rusty metal primer, shot on in say 2 to 3 coats, seals very well, maybe not like 2 k epoxy, but still very well.

I believe Mopars of the 40s were painted from the factory with synthetic (alkyd) enamel, which was baked on, repairs were quite often either made with the same enamel or for speed possibly lacquer based products.

GM used lacquer, and possibly Furd.......

After thinking about it, I believe you are correct about the enamel usage on 40's Mopars.

[Rodney Bullock]

Don, you can't use POR-15 as a primer. unless you use something they sell between it. If you want something to use as a rust inhibitor I use 'rust bullit" after it dries you can sand it and prime over it and paint. I used it on the 1961 Hawk I built a couple of years ago. No sign of rust ot chemical reaction. I used it inside the fenders and on the outside.

I have used POR-15 on my floors if you have pin holes in your floor or truck it will fill it and it's water proof. I don't use it on frames. I use the eastwood red oxide rust incapsulator. It must work as I have never had a frame rust though.

[JerseyHarold]

Another thing about the factory primers and paints on older cars is that they were lead-based and more durable in certain ways than the later lead-free coatings. Also something to consider when sanding an old finish...you're creating lead dust which is not good to breathe.

[michael.warshaw]

i remeber the op saying a story of a dog with a rhinestone collar i feel por 15 is similr to that story, makes the owner feel better even though the product may or may not work, its kind of the answer you want to hear situation in my opinion. is it that expensive?

[Don Coatney]

You should spend your retirement money on POR-15 because that's what the POR-15 people want you to do.

Pretty much what I thought:cool:

Thanks to all for the great responses!