To those of you who have used the POR-15 I have a couple questions.

1. Did you spray it or did you brush it on.

2. If you did spray it, did it need to be thinned or was it OK out of the can.

3. I am wondering if this stuff is going to be impossible to clean out of the threads of the body mounting nuts if it is sprayed in there. As hard and permanent as they say it is I am wondering if it will be hard to chase the threads with a tap if it were to get into the threads.

Just wondering, since I have never used the POR-15 I don't want to find out the hard way. I guess I really haven't decided to use it on my 71, or save it for another job.

I used POR-15 on some light rust around the battery tray on my 260, and I am about to do the same for my 240.

I brushed it on, because I had a very small and accessible area to deal with.

The POR-15 info sheets indicate that it needs to be thinned if you are going to spray it. They also recommend (and sell, of course) a filter to ensure that no moisture is mixed in during the spray process.

I would guess that a tap would not be very effective if you got the stuff in the treads, especially once the stuff has completely set.

Hopefully someone has used it as a spray, and can give you more information.

Cheers,

Steve

Can't imagine that it would be impossible to "tap" POR 15. After all, if the problem is that you got it into the threads, then use the drill bit that would ordinarily drill the hole into which you would then insert the tap, then chase the threads with the tap.

Remember, taps are made to cut threads in METAL and as hard as POR 15 is, I can't imagine it to be harder than metal.

I would think that the worst thing to happen with the POR and the tap would be that the POR would essentially shatter.

Another thing to do is to got some Plumbers caulk, it's like sticky grey plado and plug the holes. Just as the POR is getting tacky, remove the caulk and then let set. It worked for me when I was Z-Bart ing cars in Florida. It should work the same. -Rev

I didn't use the POR-15, but I used an epoxy-based truck-bed liner that I sprayed on. I had the same question regarding the thread holes on the car.

What I did was to just put a small piece of masking tape over the holes. Just big enough to cover it. (Make a mental note of where these holes are located) Then when I was through spraying and the paint had a chance to tack up, I carefully removed the little pieces of masking tape.

Since I was using a bed liner matrial this allowed for a nice smooth surface for when all my pieces went back together. And any bare metal was covered up after bolting everything back on.

I also did re-chase all my threads, but only to clean them up from rust and dirt. Every thread has been cleaned out on my car!

I assume that the POR-15 is/or similar to an epoxy paint. If it needs to be thinned out, you can use MEK for this. MEK (methyl ethyl ketone) is specifically designed to thin epoxies and you can get it at Home Depot or at your paint store.

POR is more closely related to Isocyanate glues than it is epoxy. Don't know whether MEK will thin, cut or nullify it. I do know that the POR folks do sell a thinner for clean up and for thinning for spray painting. The key thing on POR is that it uses humidity either in the atmosphere or in the rust that it is painted over to cure with.

Additionally, MEK to thin epoxy? Someone double check this, but I thought it was Acetone that you used to thin epoxies.

EScanlon, it looks like we're both right!

This is taken from manufacturing info from Crown Industries:

"Acetone- A strong, fast-evaporating solvent used for thinning and cleaning fiberglass resins, epoxies, vinyls, lacquers, and adhesives. Excellent heavy duty degreasing agent.

MEK (methyl ethyl ketone) - A strong solvent similar to acetone but with a slower evaporation rate. Used for thinning and cleaning fiberglass resins, epoxies, vinyls, lacquers, and adhesives. Superior to acetone for cleaning and degreasing applications."

I guess it basically gets down to your prefference on what you want to use. For reference, a gallon of MEK will run about $3-4 more than a gallon of Acetone (generally). I hope this information will help someone later down the road.

I've used it many times on various projects, mainly having to do with the boat. I have always chosen to brush it, but the spray instructions are on the packaging. It is a good product and very tenacious. What you put it on it usually stays on. My driveway and basement floor is testimony to that.

If you are going to use this paint I strongly suggest gloves and full coverage clothing - tyvec suit wouldn't be bad idea if spraying. If it gets on you it does not come off - even if you wipe it off fairly quickly, the stain remains.

It is also not UV stable and will eventually deteriorate in full sunlight, so top coating is manditory for anything to be used outdoors. Once properly applied, you can pretty much forget about future problems unless the part is physically damaged enough to knock the coating off, then of course the rust can get under the paint.

Well, sounds like this could be more trouble than just a coat of primer/sealer and body color. Maybe I'll save this for the real "rust buckets" in the yard and not put any on the 71. I guess under the battery tray wouldn't be a bad idea, but as far as trying to spray or brush it on the whole undercarriage, I think I'll pass on the clean-up.

Have you considered Hammerite? Its very good once it sets up and it has glass fibers in it. This makes it heavy but it works well. I Know of several places that use it on frames for muscle car resto. It does not reduce sound and takes a while to fully cure but it may be an alternative. It also does not require as much prep work as it chemically bonds to the metal. This stuff will even set up in gas.

I shot the under side of my 73 Blazer and frame with POR 15 it worked great.