removing undercoating.

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moparmat2000

moparmat2000

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we all know this job sucks badly. there are many ways to do this job, all of em suck. however theres ways to make em suck less. i found that using WD-40 on the undercoating and letting it sit for awhile loosens it up, but requires multiple applications of WD-40 over a weeks time and time to let it soak in to get it to soak thru.

i found something that works sooo much better and quicker. DOT 3 brake fluid. yes the job still sucks, but this stuff when brushed on starts soaking right in almost immediately, let it sit for a day or 2, and the undercoat will almost fall off in chunks with a metal scraper against it. i use a scraper that holds razor blades in it.

you can remove the excess with a wire wheel on an angle grinder, and follow it up with with laquor thinner and some clean cloths.

hope this helps
Matt
 
Hey Matt. I did this on my Charger and your right, it sucked bad. But the way I did it I used a heat gun (industrial strength hairdrier) and scraped most of it away with that. The residual can be had by using a rag soaked in kerosene while the panel is still warm and it can be wiped off. The more you take off with the scraper and heat gun the better the result with the wiping of the rag afterwards.
 
just an fyi brake fluid will eat paint so I wouldn't use this if your just removing undercoat and do not want to repaint the car.
 
I used paint stripper left it on for 20 mins and it came right off along with some of my skin lol
 
brake fluid also rusts the crap out of everything by drawing water. That is probably the last thing I would try. I suppose you could rinse it off with brake cleaner, wd-40 or something.
 
I used a heat gun on low setting followed by either K1 or laquer thinner to fiish up. Do not use thinner with heat gun, dangerous. Anyway, removed 35 pounds of stuff. Don't forget to reapply seam sealer. I used chaulk gun and tooled seams with my finger. Acid primed, hi-build primer, sealer, color, clear. Outstanding results, Tom
 
Propane torch and a wire brush and putty knife works really good. Do not hold the torch in one spot too long.
 
harbor freight pneumatic scraper gets most of it off. Follow up with naptha. first time, i used rags soaked in the naptha. Works but it is kinda slow. Next time I am going to use a spray bottle to keep the area I am working on wet. The stuff evaporates pretty quickly. L8r
 
I used an oxy-acetylene torch, a putty knife and a wire brush. Fast, but you've got to keep it moving to avoid warping the metal.

I removed my undercoating before sending the car off for media blast. Made the job easy for the media blaster and the result was that he did a much better job. I immediately primed the bare metal with epoxy primer.
 
PoisonDart74 said:
Whats with the undercoating removal obsession? It does it's job.
Click to expand...

I thought the same thing, until I was working on under the car and found some small holes. Naturally I started to scrape and clean the areas and found some areas under the undercoating had significant rust. I'm sure someone did it since the factory application and didn't prep correctly. I'm now stripping the undercoating, sanding, adding por-15 and undercoating! My kids will never have to worry about them!;) lol
 
When I put in the subframe connectors the undercoating was removed where the welds would be. I used a pneumatic needle scaler and had good results. Mine was not as easy as this video demonstrates, but it wasn't much harder. Here is an example:

[ame]http://youtu.be/Xha4xY-dMrQ[/ame]
 
I've seen undercoating failing off in chunks and rust through behind it. The rust grew from the inside out though. Welding in new metal is probably the most common reason for removing the undercoating.
 
I scraped off guite a bit using a heat gun. Yes, it is dangerous but worked out without using chemicals I might have to clean up. Yes, it did its job. Why? pounds of material came out, easier to work with the fender, I can paint the inside fender the same as the body, and I plan to make sure it does no trust.
 
I tried all of the above.The paint remover, heat gun,torch etc. all sucked. (Actually made it worse!!)I found leaving it hard and not touching it and using a pneumatic gasket scraper(40 bucks) the stuff came off in chunks. Did both rear wheelwells in no time.
Then after all done I used a sanding flex disc on the are and cleaned it all before it was painted!!
 

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I have tried all of the suggestions you guys have tried. Have to agree with Raaf69 it just a sanding disc forth grinder and a lot of time grinding it off. Not sure if I was doing something wrong but made a hell of a mess until I gave up. Started grinding and in a few nights I was done with it. But glad I did this since there was a lot of rust under the coating. Like some said rusting from the inside out or not properly prepped when first done.
 
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