So my 91 Bird is pretty much stripped down to nothing right now in preparation for rust proofing the interior floorpan. I also found light amounts of surface rust in the t-top channels and on the A-pillars behind the old windshield sealant. I want to paint some POR 15 in these areas before I reinstall the new weatherstripping and windshield.

I've found conflicting information about putting POR 15 in those areas, with some sources saying it's a great idea, and other sources saying the urethane sealant will not stick properly to the POR 15.

So a few questions in regards to POR 15 and sealant:

1.) What steps need to be taken to ensure a good seal with new T-Top weatherstripping and windshield sealant?

2.) There's still old windshield sealant stuck to the channels. For the T-top channels, I used airplane stripper and a wire wheel to remove the paint and old sealant, but it was a very messy process. Is there a better way to get rid of this stuff here??

3.) Floorpan seam sealer: I scraped up a ton of dried up black crud from the floorpan. I've seen posts of people saying to lay down seam sealer and THEN paint with POR 15. That just doesn't make sense.... can anyone shed some light on this line of thought?

If I can get these issues straightened out I'll be ready to put down the POR 15 as soon as the weather gets nicer. It's averaging around 30-40F here every day, so I still have at least another month (or two) before it's warm enough for it to cure properly.

 

The only one I have experience with is:

3.) When you pulled up the black crud was there bare metal or primer underneath? As a reference, I've worked at two manufacturer vehicle assembly plants and they both would seam seal after e-coat and before primer. I prefer to primer first then seam seal, however, people are concerned because they're not certain if the seam sealer will stick to the primer. In your case, my only concern would be that the seam sealer doesn't stick to the POR-15. It probably will, but perhaps a test panel is in order.

 

I can verify seam sealer will NOT stick to POR 15. I POR15'd under my t-top weatherstripping and then put seam sealer over the top of it. The seam sealer(2 part stuff from body store) peeled right off. What I did to 'solve' the issue is scuff up the POR so it will stick. I 'hope' its working.

 

Would topcoating POR 15 with primer help adhesion?

 

I don't think the primer would stick either. Por works on fact it is impervious to air and kills rust. Impervious to air also means it has no pores for paint to cling to. This is the way I understand it anyway

 

I can verify that if you prime over POR-15 while it's "open"(using a urethane primer), the primer adheres, blends, burns-in, et.al. I've done this several times and it works well when wanting to use a topcoat. I would guess that if you rough up the POR as gsf did before he seam sealed, it'd be fine.