on my 71 roadrunner, the original undercoating is just gobbed on, and I dont want to spend the time to get it cleaned off for a clean underside, so my next option is to make it look like 'new'. I know people have just sprayed more over it, but I want to see if there are any other options out there to make it look black once again. any help is appreciated.
-kevin

That stuff is tough and I leave it on as I figure nothing you are going to replace it with will last as long. I would scrub a detergent like Tide into it, hose it off and spray bomb it black.

Sheldon

I think just a really good power washing will do wonders for it. I was recently cleaning up the front splash sheilds for the Challenger. The undercoating was obviously blasted off of those pieces but it should stay on the metal parts. The small chunks of undercoating that I examined afterward looked brand new...nice and black. They didn't look anything like the brown nasty color they looked like just minutes before.

Fill a regular paint gun with slow evaporating laquer thinner. Spray the underside of the car.

If you use enough (spray until it drips) it carries away the surface dirt.

It helps if you can put it on a rotisserie and lightly sandblast the original undercoat to clean it up and also to remove any surface rust from areas that may not have the undercoat. Then go over only the original undercoat with a new coat to maintain the same configuration of what was covered. I used a gallon of a commercial product (like Roger Gibson sells) and a Schutz gun. It looks like a brand new original undercoat job. The gallon did the whole underneath and the rear wheel houses. I did have to remove the undercoat from the front fenders and splash pans on my project so that area is not just renewed like the rest of the car but if you use the right stuff and equipment, you can make it look a lot more original than a spray bomb undercoating.

Yes I have.

If the car is together & any rattle can paint was used, do not try it though.

Thanks Barry, I'll give it a try (no rattle can paint on either car)

I've had great luck with purple power cleaner and a scrub brush....A pressure washer will also work wonders.

Does anyone sell undercoat/sound deadener and a gun to get the texture and wide pattern that is factory original looking on the inside of the quarter panels? Also how about the thick body sealer and gun(i'm guessing that's how it was applied) for like the trunk/floor/extention seams or front floor pan to bottom of fire wall?

MOPARTS sponsor RestoRick sells the undercoating you want.
the seam sealer I used was really close in results other than color. I used the 3M brand 08505 fast and firm seam sealer. this sealer is beige. I used it in the trunk which was then painted over so color did not matter to me. the original sealer on my floor pan is black.

Yes, your correct on the floor pan stuff, black. Trunk gets painted over. Did you get the trunk sealer to look close to factory? If so how did you apply it? Dave

Squirt it on heavy and take the end of a paint stick and run over the sealer. Matches perfectly

I used my finger while wearing a cheap green vinyl glove.

I saw in the past where people used the paint stick method but after examining my car and using existing areas of the sealer that I did not need to address as a guide for appearence I was more than happy with my results. I did not replace any metal in the trunk. I was simply digging out and replacing dried and crumbling sealer. some areas that were very heavy with sealer I did nothing more than squeeze it from the caulking gun and leave it at that.
The car is at the body shop otherwise I would take some pics to show.

I used the rust-oleum undercoating and was very happy. It is low gloss black, with no texture.

thanks everyone for the replys! Ill first try the degreaser and see how that works. thanks again!
-kevin