hi all... new to the forum. Had my trusty road warrior Passat totalled, now looking into Turbo bricks.
a long writeup on POR 15 follows. I did a lot of reading and asking after a few suspicious reports made the stuff seem like it was worthless... I'd like to save others from having to do the same -- theres a lot of mixed opinions and experiences out there to wade through to find the truth... and honestly, I'm still not 100% sure of what the truth is.
My experience is limited, as I have yet to put the POR to the test, but my research in the area of POR use/application may be of some help.
I'm a Fiat freak... as a lot of people know, Fiats had a tendancy to rust -- I aquired a rust free Fiat 124 shell from Arizona and have been busy prepping it. Quite involved, as I have stripped (by hand) all of the undercoating, tar, etc in all of the non-visible areas of the car down to bare clean metal. Sounds crazy, I know.
This may all seem anal, but the POR 15 is apparantly not the miracle product it's made out to be.. it requires anal levels of surface preperation in order to properly work and last. I didn't want to find this out the hard way, so I followed the directions of others.
POR likes tooth, ABSOLUTELY NOT smooth surfaces.. even if it's bare metal. POR on a smooth surface will fisheye and peel away in sheets.
Wirebrushing the surface has a tendancy to fold over the tooth and conceal the pores of the metal. This is bad.
If you are going to hit the surface with sandpaper, make it a very coarse grit to provide adequate tooth... otherwise, like wirebrushing, tooth will get folded over and pores will be concealed.
The POR reps are worthless --- they will simply read from their printed instructions when you have a question.
Ask them about surface prep, and they will tell you to follow the directions, prep the surface with POR Metal Ready, and wash. Whatever you read in the directions is all you're going to get out of them.
Do NOT let Metal Ready sit and dry... you will be left with a mess that is time consuming to clean up.
Spray bottles are important to have. One filled with Metal Ready, one filled with water, one filled with Marine Clean/water mix. Very handy tools... buy them, they're cheap.
When using water for any reason on the surface, use distilled water. Minerals and impurities in tap water will (according to the experience of some) cause the POR to peel off in sheets after is has been applied. It's cheap, you don't need much of it, and it's handy to have by your side in gallon jugs anyways.
If rust is present, this is not necessarily a bad thing... rust provides quite ideal tooth for the POR to grip. Don't grind away all of the rust, just get rid of loose scale. Neutralize the rust with Metal Ready.
For bare metal, I found it was best to roughen up the surface with a COARSE sanding disc, spray with water to PRODUCE surface rust (tooth is your friend). Come back later and wipe down the surface rust with wet paper towels, let it air dry. Mist with Metal Ready, let sit for about 10-15 minutes... then comes cleaning.
Cleaning is just as important as tooth when it comes to bare metal surfaces. Impurities and loose material are the enemy.
Clean the surface with POR's Marine Clean --- soak that surface... you'll see the funk instantly flowing off. Hose the surface with water -- remember the warning, use distilled. Wipe dry. Spray again with Marine Clean mixture, and finally wash away all foreign substances from the surface with water until the water runs clean. Dry surface completely.
Sounds complicated, but it's not all that bad.
Get your POR-15 stirred and ready to use...
you aren't ready yet, but have it at the ready.
POR 15 hardens with moisture and humidity. Be cautious not to contaminate the POR-15 with moisture. POR claims it will be ruined, others claim similiar results.
Because it hardens with moisture, it is important that the metal surface (just as POR says) is BONE DRY. I used a blowtorch and heatgun -- after a few seconds of applied heat, you will see previously unseen moisture being chased away from the pores of the metal. Move fast, as you can't stop condensation -- the moisture will return when the metal fully cools.. you certainly don't want the metal to be red hot, just enough to chase that moisture away... use care not to make paint on the other side of the metal bubble from the heat.
Paint away. Not too thick, but cover the surface well.
Now you have to stick around and keep a close eye on it... once POR 15 dries, you cannot add the second coat -- it will peel right off. You have to catch it at the right time in the drying process. Hit it with a second coat when the first coat exhibits very slight finger drag -- if you touch any of the painted surface and there is little to no finger drag, don't hesitate -- add the second coat NOW.
Like I said, it's no miracle product... but my understanding is that if it's applied properly to a properly prepared surface, it will do it's job.. stray from the process and be prepared to be real dissapointed with it.. I've read too many cases of people getting poor results -- peeling in sheets seems to be the most common result of mis-application.
Here's what I know.
My 124 is coated with the stuff, I took my time and it seems to have worked out very well -- occasionally I'll get under it and punch the floor pans to test it, it stays in place... it appears to be bonded very well, although I have not put it to the real test of the road yet.
Another note: have laquer thinner at the ready -- if it gets on your skin, take a break and clean it off. If it dries, it's there to stay... you'll rub your skin raw trying to get the stuff off. I had the pleasant experience of getting it in my hair, teeth and eyes. Scrubbing the face down with laquer thinner was not much fun.. if I had acted sooner, it would have been a lot less painful!
Have fun. Good luck.
- Matt Webb