POR15 in rain gutter?

[FL71C10]

I am prepping my cab for paint. The whole roof will be stripped down to metal, and I was wondering if I should use POR15 in the rain gutter channels. I thought I would mask the roof part off to make sure that the POR15 is only in the rain gutter part. Would this be a good idea, or should I just use Epoxy primer?

Thanks!

[MP&C]

POR15 is not the end-all be-all restoration in a can that the manufacturer makes it out to be. In some cases it works, in others it doesn't. If ALL the rust is not removed, simply painting over it does not make the corrosion stop or disappear. The biggest disservice that it does is to get people accustomed to taking short cuts.

Next, POR15 is not user friendly with most automotive paints. You'll need to use a tie coat or spray over top in a narrow window of time lest your top coat peel off in sheets. That window of time is not sufficient to apply seam sealer, allow it to cure, and paint over top again. I would suggest to steer clear of this bandaid method, and use products actually made for the automotive industry that are compatible with each other. (POR is an off-shoot of Moisture Cured Urethane originally formulated for painting bridges) Your best bet is Epoxy primer. I would say to abrade the drip rail well to remove any rust and/or scale. If that does not remove all rust, replace the defective area with fresh metal. Then epoxy prime, seam seal with catalyzed sealer, epoxy prime, then top coat, allowing for curing times between, of course.

[Foot Stomper]

Originally Posted by MP&C

POR15 is not the end-all be-all restoration in a can that the manufacturer makes it out to be. In some cases it works, in others it doesn't. If ALL the rust is not removed, simply painting over it does not make the corrosion stop or disappear. The biggest disservice that it does is to get people accustomed to taking short cuts.

Next, POR15 is not user friendly with most automotive paints. You'll need to use a tie coat or spray over top in a narrow window of time lest your top coat peel off in sheets. That window of time is not sufficient to apply seam sealer, allow it to cure, and paint over top again. I would suggest to steer clear of this bandaid method, and use products actually made for the automotive industry that are compatible with each other. (POR is an off-shoot of Moisture Cured Urethane originally formulated for painting bridges) Your best bet is Epoxy primer. I would say to abrade the drip rail well to remove any rust and/or scale. If that does not remove all rust, replace the defective area with fresh metal. Then epoxy prime, seam seal with catalyzed sealer, epoxy prime, then top coat, allowing for curing times between, of course.

^^^ Exactly ^^^

[mongocanfly]

thanks for the explanation....that's the way I had planned to do mine.. my plan was/is to blast gutter,,, epoxy prime,,,3m 08505 seam sealer.......I didn't know it needed epoxy over the seam sealer though...so ill be sure to epoxy over seam sealer...then itll have the highbuild over the top.

[MP&C]

Don't know that it needs to, but I'm sure there will be a few days in between seam sealer and top coat for me, so I'd rather be scuffing on epoxy..

[FL71C10]

Originally Posted by MP&C

POR15 is not the end-all be-all restoration in a can that the manufacturer makes it out to be. In some cases it works, in others it doesn't. If ALL the rust is not removed, simply painting over it does not make the corrosion stop or disappear. The biggest disservice that it does is to get people accustomed to taking short cuts.

Next, POR15 is not user friendly with most automotive paints. You'll need to use a tie coat or spray over top in a narrow window of time lest your top coat peel off in sheets. That window of time is not sufficient to apply seam sealer, allow it to cure, and paint over top again. I would suggest to steer clear of this bandaid method, and use products actually made for the automotive industry that are compatible with each other. (POR is an off-shoot of Moisture Cured Urethane originally formulated for painting bridges) Your best bet is Epoxy primer. I would say to abrade the drip rail well to remove any rust and/or scale. If that does not remove all rust, replace the defective area with fresh metal. Then epoxy prime, seam seal with catalyzed sealer, epoxy prime, then top coat, allowing for curing times between, of course.

Thanks, I thought maybe the POR15 would be good because it would soak down into the crevices where the two panels meet, etc. I understand the issue with the compatibility, so will probably just go with the epoxy primer.

[BIGglaSS]

POS15 only covers rust until you can sell it to the next guy... Don't be that guy...

[sprint_9]

Originally Posted by FL71C10

Thanks, I thought maybe the POR15 would be good because it would soak down into the crevices where the two panels meet, etc. I understand the issue with the compatibility, so will probably just go with the epoxy primer.

You could brush epoxy in with a small brush instead.

I highly recommend a self leveling seam sealer for the majority of the drip rail, such as 3m 08307. You have to jack the rear of the cab up to level the drip rail and work to the corners where it slopes. Once that drys you can set the cab back down and do above the doors to where it slopes. Then you have to use a standard non-flowing sealer for the downward portion behind the door.

This is the result of using flowing seam sealer, my second time doing this. The first time ended up in a disaster trying to smooth out non-flowing sealer and get a nice line where it transitions to the roof. Im far from an expert but someone turned me onto the self leveling sealer and it was a game changer.

[Foot Stomper]

Originally Posted by BIGglaSS

POS15 only covers rust until you can sell it to the next guy... Don't be that guy...

Excellent advice!

[FL71C10]

That looks good. Some people fill that seam too high. Its seam sealer, not seam filler.

[Bigdav160]

I've had good luck with POR15.

But I agree it's not "great" for just any application and in other applications it is destined to fail. Personally I think it would be OK under the seam sealer however, I have never tried it.