# Por 15 adhesion need input



## FlambeauHO (Nov 24, 2011)

So now that the stuff has had several days to dry I have been doing some testing in different areas. Bottom line is that I am not thrilled with the adhesion of the POR15. All areas that were hit with a wire wheel and made too smooth were then sanded with 40 grit and prepped with the metal ready as prescribed. Its not that the stuff is peeling off in sheets or anything but scraping gingerly with a razor peels it up a little too easily. In contrast to the paint that was there from the factory which is hell to get off I am just not thrilled. This leaves me with a conundrum, I can change to something else for the rest of the undercarriage, but do I leave the POR15 even though rust may start underneath it? My prep work took a month for 1/3 of the undercarriage and I am pretty pissed  . I have no way to get the body off nor any desire at this point. It will come off next time around most assuredly. I am tempted to clean the rest down to paint, scuff and hit with undercoating but I do not want to leave anything that is going to mask rust down the road. Car will likely never see the rain again but I live in FL very close to the ocean...and salt. Ideas? sentiments? suggestions? commiserations?


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## 66tempestGT (Nov 28, 2009)

the instructions on the can say that por15 likes a surface with "some tooth". when i used it the first time i did the same thing as you. it peels right off of clean new metal and rusty metal that has been polished with a wire wheel. now i use it in places that i dont care what they look like but i want to stop the rust. floors, inside wheel houses, inside doors, inside fenders etc. i run a scuff pad over the surface to knock off anything loose then brush right over the rest. i think it is probably the most misused product on the market. i have applied it to old parts and left them outside as sort of a test and was very pleased with the results over a long period of time.

used correctly your month of prep work should have been about 5-10 minutes. and the results would have been better.


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## geeteeohguy (Feb 2, 2008)

I've always wondered why people use stuff like POR 15. But then, I'm in California, so rust out is not a big issue. The factory never used Por15, just good old paint and sound deadener/sealer. That's all I use, myself. Holds up great and easy to touch up with a rattle can. Don't even get me started on powder coating!!!!!


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## Pontiacpurebrred (Jun 22, 2011)

Question, in 40+ years paint technology has come a long way right?

Is there good reason to use a sealant like POR 15 all over a car? Key words here being all over. My 69 has been undercoated and there is a POR 15 like substance all over the trunk, floorboards and under the dash. (ALL OVER - and poorly applied I might add)

I can see using it in the trunk and inside doors and package tray ...etc, places that were a design weakness and could use a little extra protection. But wouldn't a quality paint job cover most of us?

Like Flambeau says this car will likely never see any real weather again, certainly not road salt. So what's real and what's imagined need for protection?


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## FlambeauHO (Nov 24, 2011)

So do I leave the trunk pan and monitor it? Think i will ospho the rest and spray with epoxy primer.


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## Instg8ter (Sep 28, 2010)

Pontiacpurebrred said:


> Like Flambeau says this car will likely never see any real weather again, certainly not road salt. So what's real and what's imagined need for protection?


Thats what we often forget, exactly why i left the 45 year old undercoating on, "if it ain't broke don't fix it". When these cars came from the factory they were not perfect, i have a run in my firewall that is factory applied, still had the grease pencil assembly line markings....I left it there, it's original. the undercarriages were the same way after 7 bags of coarse sand i decided i like the undercoating, no way was i gonna scrape every inch of something that no one else but me will see up close. Treat the rust, epoxy it and call it good...i used epoxy on the front engine bay frame rails where they were not coated, it's chemical and solvent proof and hard as ceramic.


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## 66tempestGT (Nov 28, 2009)

geeteeohguy said:


> The factory never used Por15, just good old paint and sound deadener/sealer.


yep thats all you need. just ask all the guys with rust from the door handles down.:cheers

if you look in a lot of the cracks and crevices they didnt use anything but bare metal. if you would have asked john delorean how he thought that was gonna hold up after 50 years, he would have probably fell on the floor laughing. :willy:


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## FlambeauHO (Nov 24, 2011)

So all that is left is to decide what to do with the POR15 that is down. Do I leave it and hope that it doesn't rust underneath? Or try to remove it?


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## Pontiacpurebrred (Jun 22, 2011)

66tempestGT said:


> yep thats all you need. just ask all the guys with rust from the door handles down.:cheers
> 
> if you look in a lot of the cracks and crevices they didnt use anything but bare metal. if you would have asked john delorean how he thought that was gonna hold up after 50 years, he would have probably fell on the floor laughing. :willy:



Hey these cars are still here...After my grandfather passed away I took he 84 nissan (that spent most of it's life in a garage) to get new tires on it so my brother could drive it to his place in Nebraska ... when they put it on the lift it taco'd in the middle because the FRAME had rusted so badly it was no longer structurally sound. :shutme

I will take my USA vintage steel with rusted floorboards and trunk any day!


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## geeteeohguy (Feb 2, 2008)

Thanks for the new expession, Purebred. Never heard "taco'd" before, but is certainly says it all. Sorry about your grandfather. Flambeau, I would touch up the por15 areas and move on. the reality is, even if left bare metal, under your ownership and care, that sheetmetal will outlast us all. No worries.


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## crustysack (Oct 5, 2008)

I used POR-15 on EVERYTHING- frame,rear end ,complete under side of body, inside fenders, fire wall, rad support, trunk, etc,etc I found the best was a freshly sand/bead blasted part. I had one 4x2" section peel off of the left rear inner fender, I scuffed with 60 grit and recoated.I think there may have been some grease or something under the paint. The rest of it I can hit with a hammer and it does not faze it.


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## 69Goatee (Aug 14, 2009)

I too coated my entire frame, upper and lower control arms, firewall, rearend with POR-15. I didn't have the frame blasted, I used a power washer, a grinder with a flap wheel and wire brush, and a die grinder with 3M 3" discs. I sprayed the parts with "brake clean", and brushed on two coats the POR. So far it is still rock solid.


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## FlambeauHO (Nov 24, 2011)

That makes me feel better goatee because yours should not have had much more "tooth" than mine.


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