So, for a number of reasons I had to do lap welds on fixing floor pan rust out. My 92 is a 3.1L so only has exhaust down the passengers side. On the driver's side I intend to use seam sealer over the weld points and then use SEM undercoating over that. My question is about the passenger side and particularly above the catalytic converter. I do have the aluminum heat shield to reinstall but I am wondering what everybody would use directly on the floor pan above the exhaust and catalytic converter?

 

Well, I called and talked to a guy at Lizard Skin about their ceramic coating. They said I should be fine by coating with the Lizard Skin above the factory heat shield. So, he said to make sure and use Epoxy Primer over the seam sealer and then apply the Lizard Skin over that. Fortunately, I had forgotten that on the seam above the catalytic converter I was able to butt weld there (been 6 months since I did that floor pan fix). So, I won't have very much seam sealer there.

Here is what I have come up with:

Wire grind/brush the weld joint
Treat any flash rust on the weld with Extend Rust
Spray with Epoxy Primer
Seam seal the joint
Spray with Epoxy Primer
Spray with Lizard Skin
Bolt on the factory aluminum heat shield

 

A bit of work, but should be good forever.

 

I talked to Lizard Skin and they said their ceramic will shield the seam sealer and even better when the factory shield is in place. So, I moved forward and bought a gallon of the ceramic and their application kit (gun). I just finished my first coat. If you use this, you really need to have a car hoist to spray it. I have my car on blocks so the floor pan is 27 inches above the shop floor. Not enough. The application kit had a straight nozzle and a 90 degree nozzle. I went with the 90 degree with such limited space. I found that the stuff platters alot and the 90 degree in a limited space probably doesn't work any better than the straight. Next coat I will use the straight nozzle. I have my shop at 72 degrees which they recommend 70. It seems that this causes it to dry really fast so I had a hard time getting it off the gun. You definitely have to clean the gun right after you finish spraying. I did the transmission tunnel, a 2 x 2 spot above the catalytic converter, and another 1 x 2 area around the area where the fuel filter goes. I used a full gun to do that much but again with the difficulty of working in a short space, trying to angle around my subframe connectors, and the exhaust pipe ended up causing thick in one spot and thin in others. Royal pain. Not looking forward to doing the second coat. So, again, I don't recommend doing this as undercoat if you don't have a car hoist and you will need their gun as other spray guns plug up.