Easy way to remove undercoat?

[LanceM]

Well as I continue to work on my 240 that has been resting for the last 15 years I have found some rust in some places of the floor pan. Nothing bad just something that needs taken care of before it gets worse. POR-15 time.

My delema is that 20 years ago I heavily undercoated the car, now I have to take some of it off. Anybody got an easy way to strip areas of undercoat?

About the only thing that I've found that works is a twisted wire wheel in a grinder, it gets the job done but is a real mess and is slow. I've thought about a propane torch with a flame spredder and a scraper but the idea of flame, tar, and my car all in the same place doesn't give me any warm fuzzys.

Any hints or tips out there??

[Zvoiture]

I am using a 1-1/2" stiff and a propane torch. Forget the spreader, it isn't hot enough (fast enough). Just use a reagular plumbing tip on pretty high. Youjust hit a spot for a couple seconds, then stick the putty knife in and start moving the torch and knife in the same direction with the end of the knife about 1 inch behind the flame. You will figure out real quick how fast you can go. If you go too fast obviously the undercoating won't be softened and the knife will just stop. If you go too slow, the undercoating reduces to a boiling, bubbling, burning gummy muss that sticks to the knife. If you just move along briskly, (it takes about 1 second to go a foot), the stuff is soft, but still solid and firm and just drops off the knife. Works excellent, and the flame scenario is quite minimal. Ventilate your area though. A wider knife won't work as well. This method also works great for Bondo removal.

steve77

[LanceM]

Outstanding Steve,

I'll give it a try, I'm tired of coming out from under the car black with undercoat! Not to mention how bad my trouble lite smells as the undercoat dust burns off!!

[drunkenmaster]

I am using anglegrinder/wire wheel.

You can click the link in my signature for pics.

I find manouvering myself under the car is the most time consuming part, the actual grinding is quite quick. What I would give for a rotissirie...

[Alan Pugh]

I used the flame method as well, although mine is on the rotisserie which makes it a LOT easier.

I only had the one fireball accident, trust me you don't let it happen more than once. One side effect though, my eyebrows didn't grow back as bushy.

Alan.

[Z Kid]

Drunken master, a rotisserie is a great idea in theory, but I just wrenched my back badly trying to get it up that high, so I guess its not worth the effort unless like me you have to do welding and dont like the idea of molten metal landing in your crutch.

I am beginning to wish I had built just a push over system, mount it to your bumper points and just push the car on its side

[drunkenmaster]

Well, i guess there are downfalls to any method and having the car on stands or a rotisserie.

My pet peeve of having the car on stands and working on my back is worming my way along the underside of the car only to have pointy wires that have shot off the wire wheel embed themselves into my back.

[kmack]

If you don't like the flame version for removing the undercoat, I used a 500 watt halogen work light. Set it as close to the body as you can for about a minute. Then move it over. Take your putty knife (1-1/2" works best, stiffer) and start scraping. The rubber undercoating softens up nicely and just rolls right off the body. There will be a little clean up left, but it doesn't take long to get that part off. It takes a little longer than using a flame, but you don't have to worry about starting a fire. And the best part, save this job until winter... those work lamps put out a lot of heat.

[2ManyZs]

FWIW, my car had a lot of "rattle-can" undercoating over the top of the original paint and undercoating in the fenderwells. I used a product called "Under-Gone" from Eastwoods, spray it on, let it sit, and just scrape it off with a scraper. They have another product to get all the tar residue off as well. Little messy, but not bad.

[LanceM]

Thanks for the methods, I like the work lite idea, I'm using one anyway and I might as well have it do something besides make me sweat!! I will probably also do the torch thing since some of the areas I want to do are pretty small.

The chemical methods I'll pass on since it wouldn't be easy to do outside and I don't care to fill the shop with fumes and then be breathing all that crap in the rest of the night! Bad enough just washing it down with a rag and lacquer thinner to get to the metal.