Scraping undercoating is the worst.

[bobs73challenger]

Been scraping inner fenders so I can metal prep and prime. Just came to say that this job stinks. Heat gun and razor blades are slowly driving me crazy.


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[moprr]

I agree the job sucks.  When I did mine I tried with a heat gun then switched to a propane torch and a scraped when it has enough heat it just lifts off nice with a scraper.

[72bluNblu]

Propane torch and a good putty knife. Makes life much easier. Needless to say, be careful with the torch and have a fire extinguisher handy just in case. Shouldn't be a problem, but better safe than sorry.

[cudamadd]

I know how you feel and would so many others ,its a tuff job just keeping your mind on  the job . Save up or if you can  it blasted the only way to remove any rust . All the best 

[Rdchallenger12]

I'm dreading when I need to do mine... someone in their infinite wisdom did the whole engine bay in that junk...

[Topcat]

Buy the Harbor Freight High output propane weed torch.

http://www.harborfreight.com/propane-torch-61589.html

Then connect it to a 5 gallon propane tank.

These things put out alot of heat so be careful.

More volume and it will work faster. 1-2 hours per wheelwell is doable.

[70chall440]

There is a trick to it, I have done it many times. I use MAP gas and a putty knife as well as a wire brush. The trick is how hot to get the undercoating; you need to get it almost to the point where it catches fire; not quite but close. You can usually tell because it will change color to a gray or flat color. Then hit it with the putty knife, it will only come off where you heated it, but if you do a decent sized area it will all be good. The bonus is that it leaves very little residue on the metal and actually comes off pretty clean. It is still messy but it can be sweep up.

[Cudakiller70]

Buy the Harbor Freight High output propane weed torch.

http://www.harborfreight.com/propane-torch-61589.html

Then connect it to a 5 gallon propane tank.

These things put out alot of heat so be careful.

More volume and it will work faster. 1-2 hours per wheelwell is doable.

Is that made by Binford tool Mr Tim Taylor aka Topcat? 

[Cudakiller70]

Some have had good results heating the putty knife then scrape.
Try an Oscillating tool
Sawzall scraper https://www.amazon.com/Milwaukee-49-22-5403-3pc-Material-Removal/dp/B0088SZE0W/ref=pd_lpo_469_tr_img_3?ie=UTF8&psc=1&refRID=35ZAKTSTX56HCC7P9T06
Mr muscle commercial oven cleaner https://www.amazon.com/Oven-Grill-Cleaner-19oz-Aerosol/dp/B00PM8YITO/ref=sr_1_4?s=home-garden&ie=UTF8&qid=1476157954&sr=1-4&keywords=mr+muscle+commercial+oven+cleaner
Small angle grinder with wire wheel wear gloves, safety glasses and face shield.

[soundcontrol]

On my car there were 2 kinds, a thick one like yours, easy with a torch, and a thinner kind inside the front fenders that was harder to get off, had to use paint thinner to get the last off there. But it did a good job protecting the car for over 40 years though, there was rust where it had fallen off, but under the remaining coating the body was perfect.

[soundcontrol]

I'm dreading when I need to do mine... someone in their infinite wisdom did the whole engine bay in that junk...

Damn. Never seen that before... picture?

[rhamson]

I used several coats of Aircraft Stripper. That and a wire brush made it somewhat quicker and bearable.

[moprr]

After scaping the major stuff I used brake cleaner and a scotch brite pad worked perfect to get the leftover. 

[Challenger in NC]

Hi Bob. This is definitely one of the worst parts of doing a restoration, but you'll work through it. Keep updating us with pics of your build.

[Topcat]

I used several coats of Aircraft Stripper. That and a wire brush made it somewhat quicker and bearable.

Nasty stuff.

I myself avoid it as much as possible.
I stripped parts using it outside only.

http://www.doityourself.com/stry/usingpaintstrippers