Undercoating?

[Fitz73Chrgr]

How do you guys get the undercoating off of your cars when you restore them?  I've been scraping it off, but it takes quite a long time and is very inefficient.  Any ideas?  How much would it cost to sandblast the bottom?

Also, did 73's have factory undercoating?

[2harleyriders]

The factory did have under coating.  It was very thin in spots and thick in others and absent in others.  My car had it all over.  The previous owner must haave had it ziebarted.  I used map gas to melt it off.  You should use propane and a scraper.  Be very careful not to burn yourself or other important things like a fuel line, gas tank, interior(it gets very hot on the other side).  Just heat it up a little for a few seconds and then scrape.  I just did the parts where people can see.  The rest of the under side I used a wire wheel on a grinder to get the dirt off and some of the undercoating and then put another coat of undercoat on top of it.  Some people say not to do this but mine is not going to be a 100 point show winner.

[BlueSS454]

I used a propane torch and a scraper, it went rather quickly until I passed my hand under the flame b/c I got distracted, that hurt a little and f'd up my hand for about 2 weeks, other than that, it's the only way to go that works.

[Silver R/T]

sometimes its easy to heat it up with a torch and then it scrapes away much easier.

[Charger-Bodie]

id sand blast it unless you are not taking the car all the way apart in that case clean it up good and recoat it with GOOD undercoating

[is_it_EVER_done?]

A propane torch is by far and away the best way to go. MAP gas is to hot, and sandblasting is an exercise in futility. If you don't have a propane torch, get a cheap one from Wal-Mart or the plumbing section of Home Depot/Lowes.

You don't really need to heat it up much for it (undercoating) to be easy to remove. You will learn very quickly as to how much heat, and how big an area to heat in order to make the job quite easy. Too much heat makes it "melty", and not enough makes it hard to scrape. Like "Goldilocks", you will find a just right temperature, and it scrapes off in a very satisfying way, which is fairly big hunks with little effort.

I use a 1" inch, and a 3/4" putty knifes that I have "somewhat" sharpend on one side. As for replacing it (if you intend to), I love this stuff ... http://www.secondskinaudio.com/cgi-bin/index.cgi?p=ps&pg=2... scroll down to the "firewall" portion at the bottom of the page. This will undercoat, reasonably sound dampen, and block most all the heat. Really good stuff for reasonable prices.

[AutoRust]

sandblasting is an exercise in futility.

No exercising here !!

We sandblast the underside of most cars and trucks that come in here. We do have a hi-volume blaster, with a rotary compressor behind it, and it is on a lift, but the results are amazing.

We also use a very high quality undercoating. Some paint on the surface first is good.Try to stay away from the stuff in rattle cans, they do not last very long.

[moparguy01]

sandblasting is an exercise in futility.

No exercising here !!

We sandblast the underside of most cars and trucks that come in here. We do have a hi-volume blaster, with a rotary compressor behind it, and it is on a lift, but the results are amazing.

We also use a very high quality undercoating. Some paint on the surface first is good.Try to stay away from the stuff in rattle cans, they do not last very long.

what he said. We sandblast cars at our shop all the time. we strip it to the shell, then put it on a custom built metal cart or sometimes up on the rotisserie and sandblast away. we use a big rotary compressor as well. works real slick. And the rattle can undercoating sucks. all it does is add a black color to the bottom.

[AutoRust]

Thanks for the para-phrase.

I guess I should  try to detail my explanations a bit more

[is_it_EVER_done?]

I stand corrected! Though I have never heard of a rotary compressor (it conjures a mental image of a jet engine strapped to a compressor tank with Tim "The Toolman" Taylor grunting - MORE POWER!). A normal home compressor/sandblasting tank won't even begin to strip old undercoating.

I am curious how a system that puts out the kind of power you guys are talking about keeps from distorting or destroying metal? I learned years ago (the hard way) that a good home system can cause all kinds of distortion even at low surface temperatures.

Also out of curiosity, what is a system like that primarily used for? I live in the desert where rust isn't an issue, so I'm guessing it has something to do with that?