sandblasting

From: Doug Fattic <fatticbicycles@qtm.net>
To: Conor Buescher < bueschc@gmail.com>,
       framebuilderslist <framebuilders@phred.org>
Subject: Re: [Frame] Blast Media
Message-ID: <C08FC904.85CD%fatticbicycles@qtm.net>
In-Reply-To: < 8d62626e0605160005n3b575366r65b01dd7ded167eb@mail.gmail.com>
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Conor,

Like Curt Goodrich, I also use aluminum oxide 80 grit.  It works fine but is
probably not the very best.  I've heard that garnet (spelling?) is a little
better but more expensive.  Special plastic media has been developed that
has certain advantages.  You can blast the frame and not hurt chrome for
example.  I've never bothered to experiment with it since I have to clean my
whole system and I don't want to be bothered.  But if starting out fresh, I
would certainly check that out at your local supplier.

I've mentioned this before on this list (I think) but I'm not much of an
archive checker.  Since I do a lot of painting I have good equipment for
these jobs.  My cabinet is 5' X 4'.  This is a nice size.  When I started,
my cabinet was 5' X 3' and that was too small.  I also use a pressure
blaster rather than a suction blaster.  It's a major piece of equipment.
Next to the blasting cabinet is a separate thing (which is bigger than my
blasting cabinet) that recycles all the media from the blast cabinet.  It
sucks the media into a cyclone separator where the dust goes one way and the
good media drops through a vibrating screen into a holding tank.  When the
foot valve is released, the media now drops into the pressure tank.  When
the foot valve is activated, a cone plugs the hole into the holding tank and
the media is fluidized like quicksand with air pressure through a special
stone.  It comes flowing out through the hose into the blast cabinet through
the right sized nozzle.  The advantage of a pressure blaster is that I can
use 40 to 50 pounds of air pressure instead of 80 like a suction one
typically needs.  More than that, a lot more media comes out at lower
pressure and so does less damage and cleans or removes paint much faster.

A suction blaster works on the principle of a T coming off of the air hose.
This creates a suction that pulls the media from the bottom of the blasting
cabinet where it is mixed with all the crud that was heavier and didn't go
out with the dust.  This system is fine but, it would be like comparing Ergo
shifters to old down tube friction shifters.  Once you get used to the
advantages, you won't want to do it the old way.

Of course great quantities of air is needed to power these things. I've got
2 Quincy 5 hp two stage compressors that don't quite keep up with the air
requirements.  I can't get more electricity to the shop so I'm maxed out.

The main point of this post is to check with your local sandblast supplier
to ask about plastic and other types of media but aluminum oxide works fine.

Doug Fattic
Niles, Michigan

> Hi,
>
> I've been thinking about getting either a blasting cabinet or a siphon
> blaster to use in the shop and was wondering what kind of media do
> people like to use.
>
> I was thinking walnut shells, but I thought I would check with the
> more experienced users.
>
> Thanks,
>
> Conor Buescher
> Vendetta Cycles
> www.vendettacycles.com