To piggyback off the old post about removing the carpet and sound deadening from the S6, here is a post about the restoration of the floor! It couldn't stay ugly forever.
The process was a mess. Absolute torture, but there was a lot of stuff that needed to go. Carpet residue, glue, sound deadening, and some paint was all removed with various attachments on my angle grinder. The majority of the work was done with a knotted wire-wheel.
Cleaning was up next. I used 20 cans of brake cleaner and a few cans of carb cleaner here and there. The amount of residue was incredible. It just kept coming off.
After this it was POR15 time. POR stands for paint-over-rust. Unfortunately this means you must create a small film of oxide for it to bond to. Chemically it neutralizes the rust and bonds to it, but it does scare me a little bit when you have a spotless rust-free car and want to intentionally induce rust. The benefit is that the floor is permanently coated in a rust-proofing paint.
The first two stages were prep. Stage one included using the diluted degreaser that comes with the kit to do a final degrease of the floorpan. After this you use their special sauce blend to etch the metal and leave an oxide layer on any bare metal. This would then be washed out with a hose to remove any residue and let dry before moving to stage 3.
Unfortunately I do not have pictures of these two stages but just image a wet floor being dried two or three times.
Stage 3 came next which was the application of POR15. I had to heat the garage to around 70 degrees and then start the application. Two thin coats of the stuff. I managed to have just enough to do the whole job.
Unfortunately I managed to get a bit of paint on the vacuum lines, but it is what it is. This stuff does NOT come off. I am still coated with the stuff on my arms a week later. It ended up working very nicely and filled in all of the cracks as it is supposed to.
Next up was seam sealer. I used 3M seam sealer and ended up using about a can and a half of the stuff. I did remove some thick sealer from the car but there weren't too many areas that needed seam sealing. Pretty much any gap in metal that was sealed before got resealed. It's easy to go overboard with this stuff so I opted not to.
Time for the final bits! A final layer of acoustic sound insulation around the car to top it all off. This is not scientific or anything and honestly don't know if it was worth it, but it was cheap and easy.
I recognize that some of the areas weren't done in a very clean fashion, but at the same time nobody is ever going to see this again after the carpet goes back in so I think it's going to be okay. I tossed up the idea of doing the roof as well but decided against it as the risk of breaking any clips far outweighs the benefits of .01 decibels.
This stuff was better to work with than the sound deadening was but the adhesive is incredible. I am going to be cleaning up the floor for a while.