Undercoating removal...Success!

[mardak at cogeco.ca (Mark)]

I can imagine removing the undercoating by hand would be a very slow,
tedious process.  I remember reading an article in GRM on the early 911
project - he tried dry ice, scrapers/heat, abrasive disc, wire wheel,
etc and gave up frustrated...  He ended up getting it sandblasted off.

I will probably do the same, but do it myself.  With a rotisserie and a
rented big-ass sandblaster, I would think the entire car could be
stripped down to metal in a weekend, with much less cursing...

Anyone do this?  What type of sand would be best?

Mark.
80 S
81 S  ABA/JH/4K

> -----Original Message-----
> From: scirocco-l-bounces@scirocco.org [mailto:scirocco-l-
> bounces@scirocco.org] On Behalf Of Neal Tovsen
> Sent: November 19, 2003 3:19 PM
> To: scirocco-l@scirocco.org
> Subject: Re: Undercoating removal...Success!
> 
> The dry ice trick does indeed work...on asphalt-based
> SOUND DEADENING. I used it on the inside floorpans of
> my Mk1 when I was doing repair work.
> 
> Undercoating is a bit of a different animal. I'm not
> sure it would work at all since it is mostly a
> combination of foam rubber and seam sealer on our
> cars. But in my case, since I didn't have a
> rotisserie, I was unable to even try it (dry ice
> doesn't stick to the underside of your car very
> well!).
> 
> I just used the torch-and-scraper routine. After you
> do it a while, you can usually get a reasonably quick
> rate of progress. The trick is to soften it enough to
> get the putty knife to slide underneath, but not
> enough to "blacken" the undercoating...at which point
> it catches fire, makes LOTS of fumes, and is tough to
> put out again. If you do it right, it will come almost
> shiny-clean.
> 
> Then you just need a flexible sanding disk on a drill
> to take off the little bit that is left. Wire wheels
> work, but the coarse sandpaper was much better. The
> best was a RotoZip with the angle-grinder-like
> attachment. They had this funky 3M-green-scrubby-like
> abrasive pad/disk that was fantastic. But after
> blowing up two RotoZips in two weekends (cheap-a$$
> POS!!), and finding out that those pads were
> expensive, I went back to the
> sandpaper-disk-in-a-drill routine.
> 
> But don't kid yourself, it will take a LONG TIME to
> get anywhere. I probably spent more than a day on each
> inner front fender. I did the inner fenders, one outer
> fender (the other was new), the firewall, and just
> enough of the floorpan so that I could weld in the new
> one. Between that and the sound deadening, that was
> more than enough work for me! Anyone who does that to
> an entire car chassis has my respect...but in reality
> probably deserves to be put away in a padded room. :)
> 
> Oh, and I tried a few different chemicals, including a
> spray-can product advertised by Eastwood as being
> "undercoating remover". It sucked. Took the paint off,
> but didn't affect the foam rubber undercoating at all.
> Don't waste your money.
> 
> Neal
>