need some help with floor plan fix, peeling the coating, POR15, etc Options

[914 RZ-1]

The M/C leaked all over the floor plan. There's some rust as well. Before I put back everything I thought I would clean it all up.

1. What is the best way to get all the coating off the floor pan? It looks like some sort of asphalt/tar paper. It seems to be peeling off okay with a putty knife. I'm guessing I use some sort of solvent to get the remaining gunk off? Heat gun?

2. I have a kit that has cleaner/degreaser, metal prep and POR15. I also want to reseal around whatever that is (plug?) in the middle with some seam sealer. What order is this all applied?
-cleaner
-prep
-POR15
-seam sealer

OR
-cleaner
-prep
-seam sealer
-POR15

Or some other order?

3. I was going to leave the POR15 as the final coat, but do I need to paint over it? The car is silver/gray, the POR15 is gloss black. It's under the carpet and under the floor mat, so it will not show. I'm more concerned with keeping the rust at bay.

4. Where should I stop the painting? At a seal? At one of the changes in contour of the floor pan? Please note that the car was in an accident many years ago (before my ownership) and was repaired, but the floor pan is still a little uneven. My concern is that the paint will wick under the tar paper, but is that even an issue?

Here's a photo, since I know we all like pictures. There is a pile of tar paper on the left:


Thanks!
-Jeff
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[technicalninja]

I'd do it the first way.

The POR 15 needs to be directly on the metal.

POR 15 turns an ugly purple if exposed to UV rays. Where you are hitting doesn't matter.

NOTHING will stick to POR15 without the dried surface being prepped with sandpaper.

Normal sandpaper will not touch it! It is EXTREMELY hard to scuff up.

POR15 has a "tie coat" primer that does actually work pretty well but it needs to be applied after the POR15 has "tacked" off but before it has hardened.

POR15 is just high-quality paint that has a serious dose of isocyanates in it.
This is "super glue".
The fumes from this will mess you up and in high doses might put you in the ER.

I once did the floor pans in a Z car and even though I had airflow I thought I was going to die.

POR15 is dangerous to work with in an enclosed space.
BIG fans. lots of airflow, and outside is SOP with me now...

You do not want to POR15 anything you are going to weld.
Removing hardened POR15 requires a grinder. Soda or sand blasting doesn't work.
Paint stripper doesn't work.
It's the most permanent paint I've ever used.
It's harder to remove than powder coating...

POR15 sells fiberglass velum cloth, This is fiberglass mat that is so thin you can see through it. It can be used to patch small holes and if done right it doesn't look like a patch. It's rock hard and you can drill accurate holes in it if you need to.