Tips for successful undercoating removal ?

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  1. Kern Dog

    Kern Dog FBBO Gold Member FBBO Gold Member

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    This '70 Charger project just happens to be an undercoated car. I must have been lucky that my first Charger wasn't....
    I may decide to strip the undercoating from the floorpans and frame rails but obviously leave it in the wheelwells.
    I've had some success by chipping it off with a wood chisel and hammer. After that the wire cup on a grinder seems to clean it up nice. The tough spots are the inside corners or hard to reach areas. Is there a spray that dissolves or softens this stuff that won't kill me in 2 years?
    I thought I remembered some story of using kerosene or diesel...Seems too easy though, right?

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  2. Chargerjase

    Chargerjase FBBO Gold Member FBBO Gold Member

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    I have heard an oscillating multi function tool works well. Also air chipper but its fricken noisy. Burning it off with a heat gun or torch, but will probably end your life. My car had an oil leak for at least 20 years of its life and the oil impregnated area just scraped off with a putty knife. Diesel and waste oil might be a good idea, although if your car is not on a rotisserie then it will be a pain in the ass.
    Eastwood makes "UnderGone" its a chemical undercoat removal product. It's not cheap like diesel, but should work well. Part# 31130Z.
     
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    • 4mulas

      4mulas Well-Known Member

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      Petroleum products definitely soften it. I had a barracuda formula S with factory undercoat which had a power steering leak. The Undercoating just about fell off the area on the floorboards behind the power steering pump, about a 2’w x 6’l strip, that had the power steering fluid on it to reveal gleaming galvanized floor boards.

      Maybe if you spray gas or diesel a few times (Both a bit smelly) and let it soak it may soften it....?? Try a test patch..

      I don’t envy your job....
       
    • Aarons Air

      Aarons Air Well-Known Member

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      My car was undercoated. The shit was hard as rock. I stripped it using gas in a spray bottle, along with a map torch & a 2 inch scraper. Once i got the bulk of it off with that, i went to gas with flat tip screw drivers & pics for the harder to reach areas. Then a wire wheel on a drill. It took days. And i had a few burns from it dropping on me. Once i had it completely off, i cleaned it thoroughly with laquer thinner & paper towels. Then i applied 3 coats of chassis saver paint with foam brushes.

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      • HALIFAXHOPS

        HALIFAXHOPS hops farmer and MOPAR only distributor rebuilder! FBBO Gold Member

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        Here we go believe it or not good oven clean works the best out of everything I have tried. Spray it on leave it for a half hour then pressure wash it off. Repeat it in the stubborn areas. Seriously right down to bare metal. Do not use cheap dollar store stuff the heavier duty the better.
         
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        • hunt2elk

          hunt2elk FBBO Gold Member FBBO Gold Member

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          A cheap needle scaler from Harbor Freight will remove the bulk of it.
           
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          • DeltaV

            DeltaV The past is already written. The ink is dry. FBBO Gold Member

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            Liquid nitrogen and then rap the area with a mallet.




            :lol:
             
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            • Mike67

              Mike67 Well-Known Member

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              Needle scaler, a heat gun, a ridgid putty knife, a long cold chisel, small hammer were the tools I used with the best results.
               
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              • 65hemi

                65hemi Well-Known Member

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                Scrape off the easy stuff with a flat scraper. Use a torch or heat gun to heat and scrape the remaining undercoating. Brake clean will help wipe off the residue. A variety of scrapers, picks, etc. will be needed to get into all the tight spots. Hammers, chisels, air tools, etc. tend to dent the metal. Reciprocating tools tend to heat and smear but not remove the undercoating. It is a slow and tedious job.

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                • Frank Mopar

                  Frank Mopar Well-Known Member

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                  The undercoat is better then any paint you put on plus it’s a good sound deadener. Why not just leave it on?
                   
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                  • Demonic

                    Demonic Well-Known Member

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                    Propane torch and a putty knife. It softens up after a few minutes. The only downside is the rising cost of propane (or MAPP gas.)
                     
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                    • eldubb440

                      eldubb440 FBBO Gold Member FBBO Gold Member

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                      this........ you beat me to it........ seconds, not minutes, lol
                       
                    • Aarons Air

                      Aarons Air Well-Known Member

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                      What worked well for me was to quickly heat up only a small area. Like maybe 3"x6", and scrape it off before it cooled too much.
                       
                    • E5charger

                      E5charger Member

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                      I used a heat gun to soften it and a putty knife. It worked great. You don't have to hold the heat gun on it for very long. Not trying to burn it off, just soften it. A flat screwdriver was used in the corners. I tried the Eastwood product in a spray can but it was too messy.
                       
                    • tnfastback

                      tnfastback FBBO Gold Member FBBO Gold Member

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                      What Halifaxhops said..........Oven Cleaner on a warm day.
                       
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                      • funknut

                        funknut Well-Known Member

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                        +1 for the needle scaler. It will take off 95% of the stuff and fast. The rest with heat, wire wheels or chemicals.

                        Heat and wire wheels would be my 2nd choice.

                        As long as you have the air pressure set to something reasonable I don’t see how it would distort the metal.
                         
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                        • HALIFAXHOPS

                          HALIFAXHOPS hops farmer and MOPAR only distributor rebuilder! FBBO Gold Member

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                          Was blown away how well it worked saved me at least 25 hours of scraping.
                           
                        • tnfastback

                          tnfastback FBBO Gold Member FBBO Gold Member

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                          It (Oven Cleaner) has become my #1 most anything remover and then Lacquer Thinner :thumbsup:
                           
                          Last edited: Feb 13, 2020
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                          • Jessejames

                            Jessejames Well-Known Member

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                            I use a hand held torch with a scraper. Doing it in a well ventilated area like outside you should be fine.
                             
                          • Torkmnstr

                            Torkmnstr Well-Known Member

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                            Torch, but when I did my car it was just with a wire wheel and a lot of patience! LOL
                             
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