Undercoating?
Thread Starter
Pro
Joined: Jan 2008
Posts: 616
Likes: 1
From: Huntersville NC
Undercoating?
I have an ungodly amount of gunky build up that basically covers the entire underside of my car. I have been assuming that it is just 45 years of tar, oil, asphalt, possum guts, etc,.... I have been spot cleaning areas w/ degreaser and a plastic type scapper when I have the car on stands periodically with very limited success. Recently I took my spare tire "holder" off and tried to clean it with almost no success. My neighboor, who is a pretty big car guy, says that when these cars came off the line a guy sprayed some kind of tar like gunk from hell undercoating on them.
A) Is this true?
B) How do you get this NAPALM off? I would like to spray something better then degreaser on there and use a pressure washer on the underside.
A) Is this true?
B) How do you get this NAPALM off? I would like to spray something better then degreaser on there and use a pressure washer on the underside.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,927
From: Washington Michigan
My neighboor, who is a pretty big car guy, says that when these cars came off the line a guy sprayed some kind of tar like gunk from hell undercoating on them.
A) Is this true?
B) How do you get this NAPALM off? I would like to spray something better then degreaser on there and use a pressure washer on the underside.
A) Is this true?
B) How do you get this NAPALM off? I would like to spray something better then degreaser on there and use a pressure washer on the underside.
Others will chime in who have taken on this tedious chore.
Melting Slicks
Joined: Nov 2004
Posts: 2,311
Likes: 223
From: Temecula CA
What worked well for me...
Sounds like your gunk is pretty similar to what I had to deal with on a '65. A thick tar-based material. Same stuff that King Tut was preserved with.
After a lot of experimentation, settled on a 2-step process that was not too messy, fairly safe, and doggone effective.
First, use a heat gun to soften a small area. Then scrape it off with a plastic or wooden implement. I like a hardwood kitchen spatula because you can keep the edge sharp by sanding. Great for paint stripping as well.
Second, use kerosene and spray it on. Spray bottle, SureShot, garden sprayer, or whatever you've got. Mist it on and let it do its job. Scotchbrite pads are great scouring the surface clean.
Kerosene's slow evaporation rate and relatively mild fumes make it a great choice. Besides, what works better than kerosene on dissolving tar??
Took me a weekend to do the entire underside.
After a lot of experimentation, settled on a 2-step process that was not too messy, fairly safe, and doggone effective.
First, use a heat gun to soften a small area. Then scrape it off with a plastic or wooden implement. I like a hardwood kitchen spatula because you can keep the edge sharp by sanding. Great for paint stripping as well.
Second, use kerosene and spray it on. Spray bottle, SureShot, garden sprayer, or whatever you've got. Mist it on and let it do its job. Scotchbrite pads are great scouring the surface clean.
Kerosene's slow evaporation rate and relatively mild fumes make it a great choice. Besides, what works better than kerosene on dissolving tar??
Took me a weekend to do the entire underside.
Drifting
Joined: Nov 2004
Posts: 1,287
Likes: 934
From: Indiana
2024 C3 of the Year Finalist- Unmodified
I used a heat gun to soften up undercoating on my 64 Corvette and then WD40 and scotchbrite pads. When using the heat gun on the underside of the fenders I held my hand on the outside to gauge how hot it was getting so as not to damage the fiberglas.
Ol Blue
Ol Blue
Instructor
Joined: Jul 2008
Posts: 232
Likes: 1
From: Parker (Denver) CO
Just finishing doing mine......lots of time on a creeper with scrapers, flathead screwdrivers, Oil Eater (get it at Costco) and a pressure washer. Eventually it will come off but you need to wear clothes you can throw away.
Racer
Joined: Sep 2004
Posts: 495
Likes: 1
From: Spokane Washington
oven cleaner
I have used oven cleaner for years, used the good swelling stuff. You can get it cheep at dollar stores. It is much gentler than you would believe, just rinse it off. You may have to use a wooden scraper.
cal
cal
