Hey all -

I'm in the midst of a ground-up restoration and at the point where I need to start making decisions regarding the bodywork...(i.e. rust preventative measures, primer/painting systems, etc).

My plan as of right now is to encapsulate the whole car in a magical rust-preventing shell of POR-15 and I was considering using their "tie-coat" primer given that it is specifically designed to adhere to the POR-15 undercoat. I was wondering if anyone here has had (or knows someone who has had) experience with this product? Also, is it ok to mix primer and paint brands, or do I need to pick one system of primer and paint?

- Steve

I think that this is an idea that many of us have had, and then eventually decide is totally overkill. Rust issues simply don't affect many areas of the car, unless you plan on running it in salt water. Once done with your resto, you should be good to go for another 30 years - provided you take a little care of the car.

The main issue is that POR does not seem to live up to its claims.

As a test, I painted a sort of rusty tin lantern in POR 15 following the instructions and using all the products (metal ready, rust converter, POR 15 silver paint) and hung it outside on a hook for decoration. It looked great for a year. Year 2, I noticed some area where there were rust bubbles. Its now in its third summer, and large sections of the POR-15 paint is peeling away.

Once you get your rust issues solved, and the body painted, you should be okay. That said, coating prone hi use areas of the car in POR-15 can't hurt. I did my floor pans with it. For the underbody, I used several coats of Eastwoods Chassy Black epoxy paint.

Zach

POR-15 is not a substitute for rust repair!


I also coated my floorpans with several layers of POR-15 *after* i fixed all the rust the traditional way (elbow grease and welding) ...
Now when i get standing water in the car, it can't go anywhere and i can safely scoop it up before it can do any harm.

If you just brush POR-15 over existing rust, it'll bubble through eventually.
There is no substitute for and

Do it once, do it right!
Andy

Having worked on numerous 70's and 80's Italian cars - which quite possibly have some of the most rust prone metal on the planet - I contend that POR-15 is a waste of time. Rust and the spread thereof has a lot more to do with the prep of the metal once it is exposed to air than with a magical coating. POR-15 is hard to prep for. It is hard to paint over (paint hates to stick to it, even primers). I found that it likes to separate, even when metal is prepped by their instructions.

Nothing beats a good prep, primer, and paint, with good materials and in a good environment.

Here are a few good threads from a hotrod forum for you:

http://www.hotrodders.com/forum/por-15-vs-...let-119795.html

http://www.hotrodders.com/forum/zero-rust-28325.html

http://www.jalopyjournal.com/forum/printthread.php?t=63136

Floor drains

Thanks for the feed back.

I was planning on performing a thorough rust exorcism before applying the POR-15 and primer. I suppose though that using it on the whole car might be a bit overkill . After reading those threads though I might even go with something else for the problem areas.

Seeing as how I will be doing a lot of this piece-meal (SP?) what is a good way to keep exposed metal from rusting, after having cleaned it, until I am ready to apply primer ?

The best way to do it is to spray on rattle can epoxy primer as soon as you are done working on the piece of metal.

In my case I stripped it down bare in the winter when te humidity is out of the air, did my metal work, and painted it as soon as the garage got warm enough to paint. I had to sand the entire car to get rid of the flash rust, though, before I painted. It was not the ideal way to do it.

Zach

If you get it down to bare metal an epoxy primer like PPG DP-40 is the way to go. if you don't have a spray gun you can always brush it on. Nice thing doing it that way is you can leave it outside and when you're readdy scuff it and apply auto paint/bondo.

POR-15 works OK, I've done severial floors with it but it's not as good as they say. If it gets any UV light on it it turns to total crap.

Which brings up the point that POR-15 is not uv stable and will break down quickly on exposed parts unless they are top coated.

I don't think I'd use the stuff as a general primer. Coating systems are just that - a system. I'm not a painter and will never be one but the boy scientist in me believes in the chemists at the paint manufacturers. They should have their systems optimized to work with each other.

POR-15 is great for hidden areas if you follow the directions. Floors, longs, hell hole, underbody but if you are going to be putting a beautiful top coat on go with a tried and true system. Besides - POR-15 is bloody expensive!

Don't get any on ya!!! I coated the underside of my car about 4 1/2 years ago and it still looks good. Por 15 doesn't do well exposed to the elements especially sunlight.

Por 15 seems to be coming up short, What are the experiences and comments do you guys have about other products.

I have stayed away from Por 15 from many of the comments I have read here in this post and in others. I have uses "Rust Bullet and Chassis saver. I know there are others. Rust Bullet claims to be better and the prep is simpler. I did had troubles getting the material to mix even enough to give a smooth even color. Chassis saver went on better. In both cases, my experience is limited and they have been on for too short of time to know about how well they are going to hold up.

So...when you say flash rust, are we talking flash gordon flash or mardi gras flash? What is the time frame within I have to work before flash rust sets in?

Ospho, Metal-Ready, Metal-Prep (or any phosphorus-based solution) will help control flashrust/microrust... but not for long.

I'm still a believer in POR-15, but has limitations. You can't put it over bubbling rust. You can't put it in a place that's exposed to the sun. Surfaces must be clean, dry and properly prepped... they explain all that in the instructions. It won't fix holes. Manage your expectations.

About flashrust - wipe ospho over it, rinse with clear water. Do a etching based wash-primer as soon as you can over that (PPG had (has?) a two-part system that I like. It has a piss-colored tint that clearly shows coverage).

Even in low humidity, bare metal will rust. My tub was bare for about 3 months. Winter, so very dry air, but there is still a little moisture that wil react with the metal. in my case, after a few days, you could see a very slight orange tinge. After 3 months, the tinge was just a little darker. 400 grit sand paper on my air DA got it brite again for epoxy.

Flash rust can happen in as little as 15 minutes. It won't harm anything in the short run, its just what common steel does.

I will probably have 1 or 2 paint bubbles in a few years from not sanding off all the flash before I epoxied, and I will deal with that when it happens. I'll probably repaint the car in a few years anyhow.

Zach

I was going to use POR-15 and did not like it i had it peel off the metal b/c it is a pain to apply i started to use Rust Bullet and found it the best one out of a couple of others i used. I sprayed the entire car before painting and it still had zero rust 5 yrs later. I tested both POR and Rust bullet on an old car i had that had visible rust on a wheel well I did this when i first started my 914 resto this 3 yr test was going on at the same time i was doing the resto on the 914 and i can see how it holds up over a couple of yrs. The rust started to come through the POR but not the Rust Bullet it was perfect. I still use Rust bullet on any rust metal that i need to protect it is easy to use and works perfect.

I use POR-15 engine enamel on my tins
Seems to stand up pretty well to all tha abuse I put it through. Don't use any of the other stuff.

On areas with surface rust, I have had great luck with acid etch primer, just DA it and wipe with alcohol 2x and prime. Let it flash and add a second coat. I've had areas that have had paint on them for 5 years now no problem.

So... it sounds like applying a rust treatment layer to the whole car might have been a bit overboard... But what areas (aside from the obvious battery tray/hell-hole) should I be concerned with applying the rust-treatment - probably going to be rust bullet?

In my opinion, a good phosphate based etch is one of the main keys to avoiding rust in the future.

I strongly recommend using one of the many phosphate based preps available.

As far as POR-15, I won't be using it in the future. I followed the directions exactly and still had an issue where it peeled right off after several months. I will stick to one of the many etching primers available with a quality topcoat. I will only use a "system" designed to work together (primer, sealer, topcoat). There are many paint manufacturers and many recommendations out there.

The best way to avoid rust in the future is to avoid moisture. My car rusted more in it's first 10 years than it has in the past 24 years. (simply because it is now only taken out on non-rainy days) The track car does see rain, but not salt. It too rusted more in the first 10 years than it has in the past 24 years.

Good luck with your project.

Try this site.

http://www.picklex20.com/

Guy that is doing my body work uses this as a metal treatment then primers over it. It works very well. Por 15 has a problem in that if you have an area that is barely exposed the rust will begin and work on the metal beneath the POR 15 treatment.

POR 15 is more akin to trying to vacuum pack a part in an effort to keep exposure out.

Picklex is a treatment and not a cover as POR is. I will be using it on the tub when I finally get a chance to strip the car down.

Looks interesting but not cheap. $127 per gallon. I think I may try it. I wonder if this is a phosphate / cleaner mixture.

No, it is definitely not cheap. I read a couple of articles comparing the two products along with another product from 3M I think, and Picklex came out on top. I also liked the fact that it didn't break down when you powder coated the piece which is a big deal for me since the majority of my engine compartment parts for my MG are getting powder coated.

If you have any specific questions, they are pretty good at answering them fairly quickly if you send them a note.