I keep getting seduced by ads offering spot sandblasters, designed to let
you sand blast a rusty patch without getting sand in every nook and cranny
of your garage and body. These use a shroud between the nozzle and item
being blasted to contain the sand and collect it in a bag. Usually,
these require very uniform, aggressive, and fairly expensive blasting
medium, but the medium can be recirculated if the device works as advertised.
In case others think these things look nifty, I thought I would review the
two I've bought so far.
"Mistral" spot blaster, purchased from Daytona MIG. It's been some time,
I think it was $75 or so.
This tool gives the impression of being very high quality construction.
Unfortunately, it does not work at all well. A variety of attachments are
included, supposedly to conform to common contours, and a brush-like
gadget is intended for irregular shapes. The molded heads are fairly
rigid, and don't deform to provide a tight seal. So your expensive grit
is lost quickly. The brush gadget conforms easily, but lets the grit out
very rapidly through the brush interstices. The unit blasts very slowly,
giving the medium plenty of time to escape. The supply bag is separate
from the uptake bag, and what medium you do manage to recapture has to be
transferred from the takeup bag to the supply bag every few minutes.
Anyone with the patience to do anything more than a couple of rock chips
qualifies for sainthood.
Eastman Spot Blaster, kit at $95.
Hope springs eternal in the human breast--that's the only excuse I can
give. Each pull of the trigger cleans a quarter dollar size spot down to
bare metal, the ad says, who could resist? I should have. This blaster
uses somewhat softer shrouds than the Mistral. If you are working on a
flat or gently curved surface, these actually conform rather well. The
supply and takeup bags are one and the same, so you can work until your
grit is exhausted. One pull of the trigger works as advertised, but the
ad never said how long that pull had to last. It has to last a
loooooonnng time.
This tool does work, eventually, on ideal surfaces. But when I tried the
edge attachment on the edge of a door, the medium was gone within a minute
(medium is $3/lb). It would have taken a pound or two of medium to clean
a quarter-sized spot on the edge of the door, because of leakage.
Still, you could use this for rock chips and parking lot dings that have
gotten infected with rust, if these are on flat or gently curved surfaces,
except for one thing. This is very possibly the flimsiest, worst designed
piece of crap tool I have ever spent close to $100 for. A sandblaster is
likely to get rough use, and indeed before I had accumulated 15 minutes of
use, I was refilling the bag and dropped the blaster head a few inches
onto concrete while trying to get the bag attached. The head was knocked
out of alignment, and it has been nearly impossible to get it realigned.
This thing actually uses one set screw that seats against a second set
screw, and O-rings pushed over the handle to seal gaps in the housing.
Somewhere in this world, there may be a spot blaster that is simple,
rugged, well built, and which actually works. The above don't qualify,
however.
Ray Gibbons Dept. of Molecular Physiology & Biophysics
Univ. of Vermont College of Medicine, Burlington, VT
gibbons@northpole.med.uvm.edu (802) 656-8910
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