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Date: Mon, 17 May 1999 12:02:03 -0400
From: Allen Patterson <kormanfastbmw@worldnet.att.net>
Organization: Korman Autoworks, Inc.
To: rtriplett@bjservices.com
Subject: Re: Don't dip that in acid just yet...
References: <86256774.0052ADC1.00@lngw1.bjservices.com>
Guess I started something here. To clarify, the plastic media blasting is
going to
remove most surface rust and loose rust. If you have some really deep rust, a
stronger abrasive may be called for since you're having to remove one layer to
get
to the next (read: sand or glass media) The nice thing is that after media
blasting, the really bad places are well defined. You don't have to shoot a
large
area to find out the actual size of the area you're dealing with. Our local guy
does both. You tell him you want it paint free/gook free/rust free, and he'll
switch over to sand or glass media after he's done all he can with the plastic.
I
always think about 1960's and 70's U.S. iron when I think of acid. It's what
they
used to lighten the cars for competition. Just dunk 'em till they hit the
desired
weight. Then there's the addendum of a Camaro being dunked, painted and
assembled.
The first time it hit the track it folded up in the middle. Guess they left
that
one in there a bit too long...
As far as warping, the best way to cause it is to sand blast the middle of a
flat
panel. It's a function of heat and the metal thinning and stretching a bit.
Fortunately, this isn't usually where the rust is, and if it is there's easier
ways
to remove it. You have to get the rust out to weld and you can't always cut it
away.
Welding warps metal even better than sand blasting. Of course, there's this
heat
sink stuff that looks like runny cottage cheese that reduces heat transfer, but
that's another thread.
Media blasting would seem to make the caustic bath more effective if nothing
else.
Good Luck!
rtriplett@bjservices.com wrote:
> >There's a far better way to get the body, frame, etc. clean without the
> >drawbacks of acid or chemical dipping. It's called media blasting. Just
> >like sand blasting, except fine plastic granules are used. This gets
> >rid of all paint, rust, corrosion, etc. WITHOUT imparting any texture to
> >the metal or warping panels. Most places charge by the hour. We have
> >a place here in NC that does it, check your local yellow pages before
> >you dip.
> >Allen
>
> I've been following this thread with much interest, since I am planning to
>start
> a rebuild on what was once my parts car. I was told however, regarding media
> blasting, that rust would NOT be removed.... is this true? I don't like the
> idea of dipping my TR3 body in caustic chemicals, but thought that this was
>the
> only way to completely remove rust. IMHO, some "solid" metal has to be
>affected
> by the dipping process, so media blasting sounds like a good idea, if it will
> remove rust. Using sand, I've been told, may warp steel, where plastic
>beading
> won't.
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