What to remove undercoating

sketchers356 · 03-08-2005, 06:37 PM

Hi,
I am going to start stripping the paint off my car this weekend God willing. However, I have not bought stripper yet. I was considering "aircraft remover" recomendations?
Also the undercoating in some areas is pretty bad and is probally the primary reason that I am going for a repaint. I am under the impression that this stuff does not want to come off using standard techniques. Is there a special method that I should use or will just regular stripper be acceptable?
Thanks for your constant help guys!

Classic · 03-08-2005, 07:05 PM

I just stipped my front wheel wells and front area, and if your talking about that Black hard underbody coating that the factory put on, go the grinder with a course wire attachment, and a scraper for those hard to reach places.

Of note wear eye, ear and breathing protection. Also remove this stuff from your skin or you might get an interesting rash. Ask me how i know.

Good luck.

sketchers356 · 03-08-2005, 07:25 PM

Im not sure if it is factory and unfortunately I cant take a pic of my car now (we are separated but not at heart). It is a thick dry flat black textured tar like substance (enough adjectives?) that appears to have been sprayed over the entire underside of the car. I assume that it is factory because it covers the seams pretty well. At the same time there was a bolt covered in the stuff so it might not have been factory.
Basically it is heavy and dirty not to mention that it is cracking and gathering water. I want it off my car. I would like to do the entire car so that this problem wont pop up again far into the future but using a grinder to the entire underbody of the car is not exactly elegant. And this site with all of the beautiful waxed underbodies is putting images into my head (albeit beautiful)
Thanks guys

sketchers356 · 03-08-2005, 07:26 PM

Oh and how did you get the rash Classic?

randywebb · 03-08-2005, 07:30 PM

Check out the recent post re CO2 blasting - see if they have that near you anywhere.

BTW, Newton was highly obnoxious, but I don't think we can call him an idiot.

Mike Kast · Mike Kast's Garage

Another RSR Clone Project

Just over a year to paint the body

I think somewhere in the second thread Pat describes a simple home made tool where he mounted a scraper to a heat gun. His restoration is a great read regardless but this seems like the best method to me.
It's certainly worth a try. Grinding is always a nasty thing to do.

Evans, Marv · 03-08-2005, 08:23 PM

Don't know about the CO2 blasting. Maybe I wish I did. But, I removed it from the bottom of my '69 and will POR-15 it after it's painted. Lots of work. I used a grinder with a knotted brush to knock most of it off. Used a scraper to get most of the rest (and places I couldn't get with the knotted brush) and finished up with a straight wire brush on the grinder. MEK will disolve remaining residue, but be careful with that stuff. Most of us know how nasty it is. I sure wish I would have known an easier way. Just had to consider it therapy.

sketchers356 · 03-08-2005, 08:42 PM

I read the post on the dry ice but I dont think that it is practical for my goals.

As a side note:
Have you ever worked Legrangian mechanics? It really puts the Newtonian mechanics that we all cherish to shame with its beauty. Perhaps not always the most straightforward way for all problems but I greatly prefer calculus to vectors.

Was Newton really that revolutionary? I feel that Liebniz formulated a more complete form of calculus, and developed the stain of mechanics that developed into Legrangian and then Hamiltonian mechanics. Try doing quantum mechanics using dp/dt=ma. Gravity? There was a strong line of scientific development in that direction since Kepler. Newton did not have this pop out of no where like the apple on the head. Rather he summated the previous work with due original thought.
His other studies? Optics, I simply dont care for that. Alchemy? Searching for code in the Torah? Is this THE modern scientist?

Again I feel that Newton was a great man. But in a book that I recently picked up for fun "The 100" by Michael Hart placed Newton as the most influential person in history, at a position ahead of God himself. While by calling Newton an idiot is of coarse technically incorrect I rather wish to assert that Newton, like all of humanity is flawed, and can not be compared to whatever divinity that you believe in be it the Platonic ideals or Christianity.

Now seriously how do I take my undercoating off. Thanks for the great info guys. What is MEK?
Keep the faith...

randywebb · 03-08-2005, 09:29 PM

Well, you could put the car upside down under an apple tree....

The Principia is a tremendous thing. Everything done has had antecedants... all the way back to the chimp/Australopithecus split at least.

- I f was going to do this, I'd hire some kid to do the worst of it... I hired two hard-working punk rockers to tear out the old RR ties on my retaining wall last week - worked great...

- I think you want to use at least two differnet techniques - one for the soft undercoat and the other for the hard stuff. Start with a good pressure washing - I got the wheel wells down to bare paint with that (all I care about).

Evans, Marv · 03-08-2005, 09:34 PM

Alexander:
Methyl Ethyl Ketone
A name like that should tell you something.

Classic · 03-08-2005, 10:57 PM

Yeah, i should have mentioned the best way is to stip everything off the car and send it to a media blaster.

If your like me and just want to check for rust and get rid of that flaking 35 year old undercoat scrape and grind.

divezic · divezic's Garage

So I've been hearing the generalarities of MEK and did a search for the MSDS information. http://www.2spi.com/catalog/msds/msds02850.html It's actually not carginogenous and is no more irritating or harmful than acetone. Not to say it's a safe thing to use, but it's not the boogeyman I have been reading about. And it supposedly increases the octane of gas while burning clean...but that's another Google search.

svandamme · svandamme's Garage

cheap ass paint remover
then a drill with a wire brush

and goggles...
and a water tap around in case you get some of the stuff on your skin ( don't worry , if you rince it off quickly , it won't burn to bad

at this point , i gave up on the scraper, even the mechanical one i had,
just useless...

enter , the wirebrush on the drill :

randywebb · 03-09-2005, 09:53 AM

Just be aware that a lot of the published data on chemicals vastly understate the risks. I just went to a seminar by Dr. Sammeul Epstein, a world famous epidemiological toxicologist.

Here is one web page from a site that he sanctions:
http://www.preventcancer.com/consumers/household/indoor_air_poll.htm

I would definitely hire some punk rockers to do the nasty stuff...

sketchers356 · 03-09-2005, 02:59 PM

Thanks for all of the replies guys.
Stijn were those rust spots visable before you removed the undercoating? It is finding stuff like that which makes me want to take off the undercoating. It seems like this is quite the task. Would it be better to just deal with the areas that need attention and leaving the rest alone? Or as it appears in Stijns case this undercoating can deteriorate leaving unbeknowst rust.

WilliamJ · 03-09-2005, 03:38 PM

I've used Naptha. A solvent available at the Hardware store.
It softens the stuff so you can scrap off the majority of the thick stuff.
As the naptha dries out, the undercoating becomes dry again and more difficult to scrape off although not as bad as originally.
Just do small areas at a time and continue to brush or wipe on the naptha as required and continue to scrape. Finish with wire brush on a drill, dremel for small areas.
Wear gloves and glasses. It worked great from me in the past.
Good luck.

tc-sacto · 09:05 PM

There was a website that showed a guy using Peel-Away-7 to strip the undercoating. I liked what it said so I ordered the product. I haven't used it yet, but the web sites account of the product made the task seem much easier than any other form of removal I have seen.
the Peel-Away 7 web sit is www.paintremoval.com. I wish I could rembember the site that showed the step by step account of the undercoating removal. For now try seaching the net for Automotive undercoating removal. If I find the site, I'll post it here. I'll also keep you all posted on how the product works for me.

Evans, Marv · 03-09-2005, 04:00 PM

Well, I tell ya, I went to Home Depot to find gloves to use with MEK. Nothing they had was very good. I looked at the use charts on them and everything was rated "poor" except for one that was rated "fair". It started to melt them the first few minutes I started using them. So, I don't think I'll take such a chemical lightly. Not planning on getting it on me or breathing much of it.

tc-sacto · 03-09-2005, 04:06 PM

Found it.
http://www.svend.net/mustang/ww73/ww73.html

(Notice in one of the links how well it worked on the tar flooring)

Dennis Kalma · Dennis Kalma's Garage

The undercoating is truly awesome stuff, I have had to remove some from my '89 and did a complete stripdown of my '75. On the '75 I had it media blasted, with the instruction that they were to take as much of the undercoating off as possible, but if it appeared really well adhered to not go nuts on it. They took about 80% off, I then went over the remainder carefully and used my grinder with a wire wheel on it to take off sections if there was even the smallest hint of penetration or rust. So far it has been about 12 years and no significant rust issues (which is good for a pre-galvanized '75).

The Wurth coating on the 89 is very tough, since mine is all factory original, I can see how they wanted to really never have rust on the car (and I don't). I have used heat to take it off, but that is slow and hard on the fingers, so I will likely do the media blast again.

Dennis