Crap Up In The Fender Wells, How do I get it off? Options

[riverman]

My PO (haven't decided if he is a DPO or DAPO yet) undercoated the car with an oil-based, tar-like undercoating in an effort to slow down Mother Rust. Not only does this stuff weigh about a 1000lbs, but it's a bitch to get off. Anything I can reach with my grinder comes off okay with a cup brush, but there are certain areas, like up in the fender wells, I can't get to. I've tried heat and a scraper/wire brush, but the stuff only gets gooey and sticks even more. I've also tried varsol, and it works on the thin areas, but up in the fenders the stuff is so thick (up to an inch) that it won't penetrate.

Short of sandblasting, does anybody have any other ideas?

[dmenche914]

Aircraft Brand Paint Remover, available at kragen auto stores in my area (might not be allowed in some areas) this stuff works, i had a 356 with same tar like aftermarket crud on it, half inch thick in some places. regular strippers didn't touch it. (I tried about three other brands, usless) Aircraft Brand is super strong, and did the trick (and surprise, there was no rust found under the tar!!!)

it is super, and I mean super caustic, it will burn your skin, even a small amount, say half a drop, maybe even a speck of this stuff, and within minutes it burns like hell, really, makes you run to the sink to cool it off. You will have a welt and a scab will form if you get it on you unless you wash it off right away. (experience talking here) It also does in my solvent gloves (however it does it slow enough that I can get one use out of the glove) And of course I need not mention eye protection.

Give it a try, it is thick thus sticks to vertical surfaces, just brush it on, and wait, then get the putty knife and scrape it off, may take more than one application if very thick tar. and do not let any splatter on your good paint.