Well. I began the POR-15 process tonight. It's a pretty simple 3-step process.
Before starting the process you want to basically remove any huge chunks of rust and any other foreign substances that are stuck onto the metal you'll be painting. For me that just required taking a flat head screw driver and scraping off some chunks of seat foam that had bonded to the rusty surface. If this were a part that would actually be visible in the car (like, say, a rusty corner of the engine bay due to a leaky brake master cylinder) I would probably have taken a wire brush to it in order to really get as much coarse rust scale off as I possibly could. But I didn't because this is not a part that will ever be seen and because I read that POR-15 sticks better the more rusty the surface is.
So once all the "foreign substance" is gone, it's time to crack open the first bottle in the POR-15 package. It's a degreaser that you coat the parts in to...well...degrease them. I would have preferred a spray bottle, but I didn't have one handy so I just poured it on. I let it sit for about 2 minutes and then hosed it off per the directions. After letting them thoroughly dry under a box fan for about an hour, this is what they looked like:
Pretty gross, right?
The next step is to etch the metal with the second product. This product gets brushed on with a foam brush (included in the kit). For our method it said to let it soak for 10-20 minutes before rinsing it off with water. I was close to the 20 minute mark. It's pretty amazing to watch this stuff work. I don't know exactly what the chemical reaction is - but the rust turns black and actually quite a bit of it dissolves in the liquid. According to the instructions if you bathe the part in this stuff for 30 minutes or more it can completely remove rust. I believe it.
Here's what it looked like after my application:
Another 45 minutes under the box fan to dry the pans off and I was ready to paint with the actual POR-15 product. (FYI - "POR" stands for "Paint Over Rust"...if that wasn't already obvious)
This was very undramatic - apart from the effect of the paint fumes. Definitely do this in a well-ventilated area. Application is via brush (included in the kit). The paint self-levels very quickly and smoothly. As you can see in the photo below - had I taken the time to actually wire brush these pans they probably would have ended up with an all-over smooth, shiny finish. As it is - I'm just happy they won't leave ugly brown rust stains on my nice red 93LE carpet when I'm done.
Photo below is after one coat of POR-15 - still slightly tacky.
What's most impressive is that this photo was shot on 1/4 sec shutter speed, hand-held after inhaling all those paint fumes.
One thing to note: this stuff takes FOR. EV. ER. to dry. I had wanted to do the top and bottom of both pans tonight but I'm going to have to get up early tomorrow to do the other side of the pans. They're still too wet to flip over and they've been sitting for about an hour and a half under a fan (on low). Granted - it's about 50 degrees out right now so that's probably not helping.
The instructions say to do 2 coats. If I have enough paint left over I may do a second coat on the bottoms of the pans. No sense in doing 2 coats on the pan tops because they'll be covered in foam and leather, in the end.
If you're reading this and so inclined, you can actually sand, prime and topcoat POR-15. So if you're restoring a rusty part of your car that people will see, this should make for a good stop-rust solution that you can cover with a spectator-friendly finish.