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My Summer With POR-15
Paul Seminara

This starts as an innocent summer tale. I'll skip the procurement details by just saying I easily obtained a 1981 262C Bertone with 170,000 miles for a rather small sum (I bought it from a used car lot with a credit card!). I wanted a "project" car to satisfy my mid-life crises. After I received my wife's blessing, I drove the car home under its own power.

The interior was in great shape (well, I did replace the crumbled lumbar support for a major improvement). The engine ran well at higher RPM -- it idled pretty rough, but I remedied that for the most part although I still have some fun work to do. I replaced all steering and brake parts (including stainless flex brake lines), so it tracks and stops great! The Bertone body is fairly straight with an assortment of the 170K dents, dings and oxidized paint. The driver's door was tweaked from what looks like a break-in attempt. Nothing major. Except for some nasty looking RUST.

Rust. away quick. Don't buy a rusty car. We've all seen 'em -- the rusty "ventilated" '73 145 to the relatively minor '85 245 tailgate "oxidation." I think some people would buy a car with a dead $1500 engine before they would buy a car with one "rust hole" in a replaceable $100 body panel. Don't get me wrong; I hate rust as much as the next guy. Ever since doing battle with my very first car (1971 Datsun 510) I know existing rust never sleeps, but it can be killed. One must choose rust battles wisely.

There are ways of preventing rust, and eliminating existing rust, before it gets out of hand. On my 262C, the nasty-looking rust was on the tail panel around the left tail light extending towards the center of the rear panel very near the license plate holder. What made this particular rust look so ugly? It appeared to have originated from some corrosive material, as if someone had spilled liquid on the paint and it had splashed, chemically dissolving the paint and etching the metal. Ugly, disgusting rust.

Before I get into how I attacked the rust, I must list my dubious credentials and lack of experience. I love working on cars (read: Volvos). I do have a BS in Chemistry, but that was mainly the organic kind, and I've been a Quality Engineer / QA Manager for the last fifteen years. I can't contour a body panel (with or without Bondo), nor can I paint with anything but a brush or spray can. I have a little knowledge of mechanical rust removal.

The first thing I did to attack the rust was to gain some knowledge. What should I do? Who should I talk to? So I did what I do during any crises: I surfed the Web. I looked at a few car magazines. Someone at work had done a full 1965 Mustang restoration and had used a product called POR-15 to cover some rust. Yes, I'd heard of it. It's in the IPD catalog. This person said they had a quart can at home that I could have if wanted. I had also had used some "rust conversion" products in the past, with mixed success. Based on this knowledge and Volvo "chat" input, I decided that I needed something more substantial. I really didn't scientifically evaluate any other products.

My mind was made up to attack the rust with POR-15. The ownership of the can was transferred and I was very curious about the plastic wrap between the rim of the can and the lid. I couldn't wait to try it, but I needed some free time and some instructions. I read the can -- enough information to do a small trial area. I waited until my day off. First thing to do was prepare and clean the area. The instructions on the can weren't super-specific on preparation and didn't have a ton of useful information as to what a "well prepared surface" is. I picked an area of about 1.5" in diameter to try the stuff. I wire brushed the heck out of the area down to bare metal and hard rust (more on hard rust later). It looked like a "well-prepped" area.

Time to open the can. The lid was stuck. I mean really stuck. Lesson #1: the stuff bonds. The plastic wrap obviously did not serve it's purpose. So, I yanked and pulled and, well, it's amazing what you can do with a sharp punch and a sealed metal can. I poured it into a dry, clean, brown, 1 qt. H2O2 (Hydrogen Peroxide) bottle. The stuff in the can was jet black. Lesson #2: the stuff bonds and is light sensitive. I cleaned my funnel with lacquer thinner. Lesson #3: POR-15 (in the liquid state) is soluble in lacquer thinner.

Finally, I was ready to paint it on. On the first brush stroke, the POR-15 dewetted immediately. In other words, the POR-15 didn't stick to the metal or the surrounding paint. I wiped away the still-liquid POR-15 with lacquer thinner and gave up for the time being. Lesson #4: the stuff bonds but the surface must (and I mean MUST) be free from silicones. My paint wasn't silicone free. You remember, I bought the car from a used car lot. Their idea of spiffing the car was to machine rub it out (rust and all) with a cheap silicone product. My meager wire brushing only spread the silicone to my new wire brushes and from the paint to the "bare" metal. I had to really clean my wire brushes to get the silicone off.

Back to the drawing board. In my frustration, I looked at my hands. Whoops. Cured POR-15; this was Friday. Lesson #5: I went to work on Monday with black POR-15 on my hands.

I called the POR-15 manufacturer. I wanted some literature. I wanted my hands clean. I remember seeing the "800" number on the POR-15 web site, along with a promotion for a $10 starter kit. I ordered the kit and asked for everything in writing they could send me. Little did I know it, but this was the best move I had made so far. The kit came with gloves (what a novel idea), paint brushes, a little bottle of Metal-Ready and cute little jar of POR-15 with a screw top lid (another novel idea). For $10, one could do worse. Their guy asked me what color. I asked about colors and he proceeded to describe the colors and the difference between them. I settled on silver because it allegedly has the ability to fill irregularities in metal surfaces. My rust had irregular surfaces.

The box arrived the next week with some other boxes -- I had mail-ordered almost everything for the restoration job, so boxes on the porch are a regular thing! Everything that was promised arrived, plus lots of reading material. Some things I learned immediately were that a clean surface is critical (well, I sort of knew that one). Metal-Ready is a surface preparation agent that is applied after the surface is cleaned to promote bonding. You should always wear gloves when handling Metal-Ready or POR-15. I studied the instructions well.

So, that Friday I cleaned the rusty and surrounding areas with 100% Castrol Super Clean (I knew to wear gloves and eye protection -- this stuff contains some strong alkalines). It will damage good paint (and aluminum), but I wanted the surface clean and the car needs a paint job anyway. Please pay attention to this because it is different from the POR-15 instructions: I recommend cleaning the surfaces (rust and all) prior to any mechanical abrasion.

First the instructions say to "wire brush [the surfaces] to remove dirt and loose flakes of rust." This is an excellent start if you have a frame or a hunk of rusty metal that is crusty and has flaky surfaces, but rusty areas adjacent to silicone-slimed paint are a different story. The area should be cleaned with a strong chemical cleaner first, rinsed very well, dried, mechanically abraded, sanded and cleaned very well again with some good modern chemicals and rinsed free again.

POR-15 sells a product called Marine-Clean for cleaning, but I have only just begun to evaluate it. It seems to work OK; milder than Castrol Super Clean.

If you skip the chemical cleaning first, you stand a good chance of smearing and embedding dirty stuff and silicones into the rusty pitted areas, making it harder to clean during the "final" chemical cleaning prior to prepping with Metal-Ready.

POR-15 (and other products) make the claim that you can apply them directly over rust. I believe them, but we are talking about exterior body work -- I think a little common sense may be in order here. If you have flaky, crusty rust, an attempt to remove all rust must be made. What I recommend is wire-brushing (with a selection of wire wheels and cups on your electric drill) and sanding down to hard iron oxide. In body steel, this has a dark brown / black appearance and should be as hard as the surrounding metal. When you are down to a few small, hard, clean pits, it is time for the final clean and rinse. Allow the surface to dry or blow-dry with a heat gun or hair dryer. Don't use oily compressed air.

You should now have a clean, dry surface. If not, go back to the previous paragraphs. Metal-Ready is a metal "pre-primer" that contains some zinc compounds in a solution that will "neutralize" rust and micro-etch the steel. It is not a cleaner. Pour some Metal-Ready in a clean container (using your gloved hands) and brush it on. If you bought a larger container, you can spray it on. This is really when the fun part begins. Keep the metal wet for at least 30 minutes. If it starts to dry, apply some more. It may bubble and fizz (cool), but keep it wet. When the time is up, rinse and allow the area to dry completely.

Thank the Volvo gods, because the metal is now ready for POR-15. With your gloved hands, stir the container very well, remove some POR-15 from the original container into a clean small non-metal working container. A clean scoop works great. Small plastic or glass containers are best. We are accomplishing two things here: first, not to get POR-15 in the threads or rim of the container and second, not to put your brush in the original container. The reasons are fairly obvious: you won't get the lid off and you don't want to contaminate your valuable POR-15.

So now simply brush on a thin coat. The silver must be kept well mixed, because the metal must be kept in suspension (I think the silver flows better than the black, though). Flow it on nice and smooth. Then wait.

If you are planning to cover it with paint later, there are two options. Well, maybe three -- remember when I mentioned that POR-15 is light sensitive? This applies to cured POR-15 as well. It will not lose its rust-preventative abilities in sunlight, but it will yellow and look ugly. The other two options are to prime while tacky, or sand and prime after full cure. Priming while tacky is tricky but works great. To prime while tacky, you must allow the POR-15 to get to the perfect tacky cure,. (This could be from two to six hours!) If not cured enough, the POR-15 will still be out-gassing, and the primer will look crazed and will ruin the sealing / antirust properties of the POR-15. If you wait too long, the primer won't stick to the slick-cured POR-15. Sanding and priming after curing allows more time to goof around on something else -- like eating dinner. When fully cured, just sand with some 400 / 600 grit or so and prime with good primer.

Anyhow, POR-15 recommends thin consecutive coats. This is sound advice, but how much time and patience do you have? I found one or two decent coats to be adequate. I think if you really need to build an area up, then perhaps another product, such as the POR-15 epoxy putty, may be in order. The only place I've really poured it on was the crusty battery tray on the 262C. I just cleaned the tray, knocked the scale off, cleaned it again and put the black on really thick. I waited and sanded, which was a major hassle because of all the nooks and crannies. The POR-15 didn't stick all that great. I used the "free" black POR-15 which I now suspect has "expired," and the tray appears to be heavily silicone coated. Weird, huh? The used car lot soaked the battery with some silicone stuff to make it look new!

In summary:

  1. Clean the surface well. Rinse well. Dry.
  2. Mechanically abrade the surface, if necessary. Rinse well.
  3. Clean the surface well again. Rinse well. Dry.
  4. Apply Metal-Ready per instructions. Rinse well. Dry.
  5. Coat with POR-15 per instructions.
  6. Top coat or prime as required.
Notes: Follow all instructions when handling all of the above. Wear gloves.

Unless you plan on coating a huge area at once, stick with the small screw-top jars. Most body rust on cars worth attacking shouldn't take more than a pint or two, so stick with the small jars. Heck, POR-15 sells the jars in mix and match six packs! It is more economical to buy the larger quantities, but it is much harder to deal with. POR-15 does have a shelf life and loses its properties when exposed to moist air. Plus, if you do dribble some on the external threads of the jar, it is much easier to wipe than the inside of a can rim. Keep it sealed tight in a cool spot.

So far, the POR-15 is holding up fine on the Bertone. It is a primer-mobile, but next summer I will be ready for the paint job. I got lazy in a couple of spots and just took the good old route of spraying gray primer over bare metal (didn't feel like getting the POR-15 out) -- these spots are already starting to rust! I will now sand and POR-15 these spots as well.

Holes and rust-through are something I didn't address in this treatise -- POR-15 claims to work on these as well, but, obviously, there will be much more work when you have holes. POR-15 sells a "steel reinforcing fabric" for hole patches, but let's face it: nothing beats the original sheet metal (we're talking Volvos here, not Hyundais). Patching has real limits, mainly because the steel is more likely to rust on the "backside." I think if you have a pinhole or three, welding the hole closed, then POR-15-ing it may be the way to go.

The preliminary bottom line: with proper use and attention to the details POR-15 seems to live up to its claims.

If after all this you are interested in checking out POR-15 products, surf over to their web site. The site wasn't much last time I checked, but go ahead and get their catalog or order the $10 trial kit. The catalog is fairly slick, with manifold paint to fuel tank repair kits, there is plenty of stuff for fellow Volvo nuts, and I can't vouch for their claims on the products I didn't try!

Also, shoot me some E-mail at if you have questions, doubts, or just for general harassment.

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