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]

But it does appear you are promoting the use of POR-15 which many would argue is a crap product with no good/useful application.
LEAD, was replaced by plastic for good reason & is generally no longer used (except in small specific handcraft resto circles)
There is a better METAL solution to fixing the pinholes in areas that are determined to be solid enough to keep, its called BRAZING (IMG:style_emoticons/default/rolleyes.gif)

Those who have failed with POR15 didn't use it properly.

My Dad has been building fiberglass parts for years. I have a bunch of experience in the use of a variety of filling chemicals,

I'm not even sure you can do lead work any longer. I haven't done any in a couple of decades.

Every single use of a plastic filler on a steel bodied car will shrink with age. Somewhere down the road, you will see it "print" out beneath your paint.
If you have a garage queen that never sees sunlight it might take a real long time.
Out is the sun every day, the repair will show back up more quickly.

I agree with you regarding brazing over POR15. Brazing requires a much cleaner surface/parts to work properly and a user really needs a bit of experience before trying to braze holes in a 50-year-old floor pan.

Brazing is the second-best way to fix pin holes right after tig/mig and a brand-new panel.

POR15 can be used by a DIY guy easier than brazing.
Brazing is far better however.
Brazing is cheaper in the long run as well.