undercoat removal

Discussion in 'Tips 'n' Tricks Topic' started by 70-SS/RS-L78, Sep 16, 2003.

  1. jeduffey

    jeduffey Veteran Member

    Aug 24, 2002
    Garwood, NJ, USA
    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?
  2. KWIK 73

    KWIK 73 Veteran Member

    Feb 25, 2002
    I've heard easy-off oven cleaner does a good job (plus it's more environmentally friendly than kerosene puddling in the driveway) [​IMG]

    73 Camaro RS, LT Type
    69 Camaro
  3. D Stroud

    D Stroud Veteran Member

    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.

  4. PapaWheelie

    PapaWheelie Veteran Member

    Oct 1, 2003
    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.
  5. Matt T

    Matt T Veteran Member

    Nov 12, 2003
    Pawtucket, RI, USA
    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)
  6. krabben1

    krabben1 Veteran Member Lifetime Gold Member

    May 16, 2007
    ( . Y . )Delco
    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.
  7. 3SLO5

    3SLO5 Veteran Member Lifetime Gold Member

    Jan 7, 2001
    Edison NJ USA
    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.
  8. 77RS

    77RS Veteran Member NastyZ28 Sponsor NazstyZ28 Sponsor Lifetime Gold Member

    Oct 18, 2006
    Asheboro, NC
    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. ;)
  9. protour73

    protour73 Veteran Member Lifetime Gold Member

    Sep 21, 2006
    West of Chicago
    this is my standard answer to this question.....and it involves no chemicals, just elbow-grease:

    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;)
  10. BTTB71SS

    BTTB71SS Veteran Member Lifetime Gold Member

    May 10, 2006
    Harris, MN
    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:)

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