HELP!!
There has to be a better way to remove all this freaking undercoating from this car.
I'm open to any and all suggestions.
"What a mess" I want to paint the underbody but I look like a coal miner after laying under this car and trying to scrape it.

Use Kerosine. It'll cut the petroleum based goop right off.

Kerosene works ok, little slow, but just keep brushing it on and it will do the job. Used a propane torch and a scraper too, works pretty good when you can get to the area.

just be carefull with the kerosene and torch or you won't need to scrape anything

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Yahoo messenger ID archemedes74 feel free to add me
Give blood play hockey!

<font face="Arial,Verdana" size="2">Originally posted by tom3:
Kerosene works ok, little slow, but just keep brushing it on and it will do the job. Used a propane torch and a scraper too, works pretty good when you can get to the area. </font>

As a High School student, my friend set the passenger seat of his parent's car on fire because he used an arc welder for an instant on a 30-second fix, metal shop muffler project. The heat from an arc welder may be different, but a flammable upholstery in the interior is the same.

This is something that I am doing right now. I am cleaning up my engine compartment, and with everything off, I am taking the opportunity to remove undercoating and lots of dirt and oil from my subframe and then painting it with POR. It is a truly messy job, no doubt about that. Here is what I do to minimize mess, and do it quickly and cheaply. Get a putty knife and scrape off the undercoating as much as you can and get down to the metal. Dump the stuff as quickly as you get it off, otherwise you'll get it on the bottom of your shoes and track it everywhere. Track into your house, and you'll catch hell for it. Then I use Stripeze, a water soluble paint stripper. Any of the water soluble strippers should work, but I like Stripeze best. I put some in an empty baby food jar and use a small paint brush. Get those cheap 1.5" horse hair brushes at Home Depot. The first couple of coats I wipe off with old rags or paper towels. By this time you should be seeing bright shiney metal (at least in spots). After applying the third coat of stripper, I hand wire brush the area. Then I mist a coating of water and apply liquid laundry detergent using another paint brush (3" horsehair). Then I spray water liberally until clean using a spray water bottle. I use a large flat container (clothing container for fitting under a bed) to catch all the water as it drips. Then you are ready to treat with POR products or you can eat off it if you prefer. I usually have to repeat the process one more time after the treated area dries, but that is usually it. Let me know how you make out. Good Luck!! http://www.nastyz28.com/ubb/biggrin.gif

This truly is a mess. I am trying to get as much off as possible with a scraper, I tryed the kerosine on a spot that I had scraped and it works pretty good.. Smells like hell though. BTW, MAP79Z28 I got the carpets already.


[This message has been edited by 70-SS/RS-L78 (edited September 19, 2003).]

My car was a Cali car originally and for some reason had undercoating 1/2" thick. I used a cup shaped twisted wire thing on my angle grinder. Works great, but messy as hell. Just one of those jobs that you gotta do though. The results are worth it.
Make sure you wear all the gear, goggles ,hat, coveralls (paper so you can toss 'em) gloves and a mask.

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73RS/LT/427

Get a cheapy 1/2 or 1 gallon pressurized garden insecticide sprayer (about $15). Fill it with kerosene (even diesel works). Let it soak in for a day or two. Rent a true steam cleaner (not a pressure washer). The crud will come flying off like chunky expresso, sometimes to bare metal and you don't even get your hands dirty once. Just make sure you can get the car up high enough to lay on a creeper and spray the whole underbody from every direction.

Will kerosene or diesal do any damage to the rubber bushings or brake flex lines,rubber fuel lines?

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Drive it like you stole it.

Psychohamster that sounds like a plan, I am going to get the car out to the driveway though. I don't need that mess in the garage. At the rate I am going now I will be doing this till next year. There has to be at least 5 coats of this muck on the undercarriage. They even coated the rear and fuel/brake lines. I am ready to recruit one of them guys standing on the side of the road with the “will work for food” signs

Taking out the gas tank is a big help also.

I must admit I have never tried kerosene. My impression with any solvent is that there is always some residue that remains behind. And you have to content with that odor. Not to mention the fire hazard. The stripeze that I mentioned about is in a gel so you can slop it around and it stays put. At the end you can wash it off with detergent and water and you're done. That washes away most of the residues that otherwise would remain in the nooks and crannies. If you collect it all underneath like I mentioned, you can do the work in your garage and you wont have to go outside. Once you scrape away most of the undercoating to begin with, the rest is getting down to the bare metal. I think that one thing we all agree on is that it is a messy job. But once done, it's done! And if you POR it, you wont have to do it again.

I'm in this process right now also. I was just going to clean it off for now and paint over it until I could do it later. Well years of a leaky motor I guess soften alot of the undercoating and I used a little puty knife and scrape about half of it off prety easily. I used low odor mineral spirits to soften mine, not as bad of a smell. This is definitely the worse job yet!!!

<font face="Arial,Verdana" size="2">Originally posted by MAP79Z28:
My impression with any solvent is that there is always some residue that remains behind.</font>

Not true, based on the fact that water is also a solvent.

I removed the undercoating from my 72 RS. I used the kerosene method. It worked fanstasic! I tried the steamcleaner didn't work that great, got just as much off with my own pressure washer. But the kerosene did a good job, could scrape most of it off with a razor knife. Wish I would have done this way a couple of years ago when I did my other car. Thanks for the trick guys. Jim

I used a heat gun to heat the stuff, and then a putty knife to scrape. Then I wiped off what was left with a kerosene soaked rag.

I tried soaking it with about everything. The most softening I found came from brake fluid. I used a heat gun as well, if you get the stuff hot enough it will almost fall off in big chunks. Finally, I used a wire brush wheel on my die grinder and got it REALLY clean. Good luck, it is a tough, dirty job, but it is part of any resto or good restification.

Try easyoff oven cleaner

As I read these posts I think about the disposal of all this gunk that I'd be removing. What do you do with it? Even if you catch it in a large flat container (great idea!) then what, you can't throw it in the trash, can you?

With the comments on heating, it makes me wonder if a freezing tactic would work? I helped a friend with a '69 Catalina and the stuff was so old and dried it came off in big hard chunks. Kind of like the cracked hard dirt in the bottom of a dried up desert arroyo. Anyway, could a spray of liquid Nitrogen be a clean and swift method?

I've heard easy-off oven cleaner does a good job (plus it's more environmentally friendly than kerosene puddling in the driveway) http://www.nastyz28.com/ubb/wink.gif

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73 Camaro RS, LT Type (http://tigernet.missouri.org/~g6007/camaro/73camaro.html)
69 Camaro (http://tigernet.missouri.org/~g6007/69camaro/index.html)

I just finished doing this on the firewall of Amye's 79Z.

Don't waste you time on the oven cleaner. Although it is fantastic for removing grease and gunk, it did not budge the undercoating that was sprayed over the penetrations in the firewall.
Kerosene will soften it enough to get it to scrub off but you will need to apply several times then scrape or scrub apply again....until it all comes off. Took about three times to get it nice and clean.

Dwayne

Just a thought - I have been in the process of removing rust-proofing sprayed into my engine compartment on the firewall, inner fenders and radiator . Motor degreasers and kerosene works but the smell is awful and makes the passenger compartment smell. I went to walmart and bought some lamp oil - kerosene used for decorative lamps in the house. Works well though slow going - but no stink.

Anybody tried sandblasting? Not with your home siphon feed setup, with an industrial pressurized blaster. I've got a local place, Auto Rust Technicians, nationally known for their work on Mopar stuff. They quote $3-400 to completely blast and recoat the underbody. I know how long it took me to do just the front subframe and with all your stories this isn't sounding like a bad price to get the floors and rear finished.

Matt T
70 Formula 400 (running, needs body patches)
71 Camaro in pieces (long term project)

Reviving a dead thread,live on!I just got done the pass. side wheel well.Im using the propane thing and scraping.Coming off good.Minimal residue to deal with on clean up.And Im seeing brand new looking red oxide primer under everything.Drivers side tommorrow,hope I didnt jinx myself.

man back from the dead is rite i was going through the names on the side and havnt seen any of those in like 2 years time.

A while back someone mentioned using mineral spirits to remove the undercoating. I tried that and it worked great on my wheel wells. Just brush it on and let it set for a few minutes and it chips right off. The propane method worked good, but the mineral spirits were a lot faster for me. According to the info I got from GM, that undercoating has asbestos in it. I figured the mineral spirits were an easier way to keep the dust to a minimum as well. ;)

this is my standard answer to this question.....and it involves no chemicals, just elbow-grease:

http://i145.photobucket.com/albums/r204/protour73/Undercarriage011.jpg
DeWalt grinder, about 7 wire wheels, few hundred pair of latex gloves, steel wool, Eastwood's PREP spray, heat gun, wire detail brushes, a face shield, 7 cans ZeroRust Red Oxide (yea it's a rattle can).

Put the wire wheel on the grinder, go nuts in 2' x 2' sections, heat gun and wire brush for the hard to get to spots, after its all done, go over the entire undercarriage with the steel wool, wipe down entire surface with the PREP spray, shoot with the ZeroRust Red Oxide. Wear the facesheild to protect your face from the little wires flying off the wheels....oh and about a month and a half of your spare time. And this was all done with the shell of the car up on jackstands....no rotissery.......Good Times;)

Propane torch and scraper for some areas, if it is dry enough air-chisel on lowest setting and go at it...... Then goo gone to clean the rest of the undercoating off... Then sand blast:)

Or,ENCASE in POR15.