Since making the review of the
California Air Tools air compressor,
I've had a number of people ask me about
the sandblaster that I'm using. It's a
single piece molded plastic bench top
unit from Cyclone Manufacturing of
Michigan. This model may not be available
anymore. I got this one from seller on
eBay. I'd previously owned another
sandblaster from Cyclone. It was a floor
standing model single molded plastic
version as well. I really like these
molded plastic sandblasters because
there's no seams for the abrasive to seep out.
In this video, I'd like to show you some
improvements I made to the sandblaster.
Later in the video, we'll look at how the
sandblaster performs on the California
Air Tools compressor. The sandblaster doesn't
have a great deal of circulation and
there's a lot of debris that gets kicked
up in the air obscuring vision. There's a
large ventilation port on the back but
the only thing that this does is let sand
escape. The glass beads creative
bearing surface and can be really slick on
the floor. There's another crudely cut hole
on the side I suppose for some type of vacuum
attachment. The hollow legs capture about
a liter and a half of abrasive. This would
be okay except when you go to change
the abrasive. You may want to clean that
abrasive out to prevent
cross-contamination. We'll fill the void
in the legs with concrete. First we'll use a
crevice tool on the vacuum to clean them
out. Before returning the abrasive to its
bucket, we'll sieve out any large chunks.
I've had this little fishnet since I was
eight years old and before that my
brother probably used it. For blasting, I
mainly use glass beads. They work well
for aluminum parts to remove machine
marks and leaves a nice matte finish. To
fill the hollow legs we'll use eight
pounds of cement patch. I didn't know if
the cement would stick well to the
polyethylene but there's a polymer
admixture that's in this patching
compound that maybe helping it
to adhere.
Mike, if you're watching, let me know if
you need any purple gloves. The eight pounds of cements
also helps to stabilize the
sandblaster on the bench. Without that
extra weight, that blaster has a tendency
to move around. The next thing we'll do
is improve the ventilation system, first
by removing this rear grating. We'll use
the rear larger hole for attaching the
vacuum and the side smaller hole for the
air inlet.
This is a solid model of the parts we'll
make to improve this ventilation. The two
larger rectangular parts are baffles
that mount inside of the same blaster. The
baffle on the left side has a couple
extra bosses that provide support for
the vacuum attachment. The vacuum
attachment is a loft surface that
transitions into a flange, has a slight
taper to it to receive the vacuum hose.
The vacuum adapter slides through the large
hole in the rear of the sandblaster and
then a cover plate fills any gaps
around the vacuum adapter. All the
ventilation improvement parts are 3d
printed in ABS. 3d printing really shines
on a part like this. Thin wall, lofting
surfaces, slight taper. I'm sure this part
could also be made with subtractive
machine but it just seems like there'd
be a lot of waste in doing so. On Taz5 3D
printer and using Simplify3D the vacuum
adaptor took about an hour
and a half to print and the baffles took
about two hours to print.
Mainly I print with hundred percent infill
and that lets me do secondary
machining operation such as drilling. The
drilled holes then receive heat-set inserts.
These are pretty useful. I'll make a
supplemental video in case you have an
interest. For manual drilling and cutting
it's hard to beat a full-size template.
Before I install this, I'll show you the components.
We have this baffle which goes on the inside
of the sandblaster. This is the vacuum
adapter which goes through this large through hold, and
then on the outside, there is a part that
surrounds the crudely cut hole, just to hide it
a little bit, and we'll put screws through all
these holes and that is what will hold everything in place
With the ventilation system in place, and the
vacuum running, a quick test to see if we
have vacuum in the the cabinet.
These are 60-120 mesh glass beads. The pail is
fifty pounds and I put roughly a third
of the pail into the blaster.
The nice thing about glass beads is that
they remove crud off the surface without
affecting the surface much. This is the
base of a hummingbird feeder and I think
it's made of copper. This part of the
great example of what I'll use the blaster
for. It's a part that's has been machined on the
CNC mill and there's machining marks that
remain, and I just want to clean those
off and get uniform finish. This leaves a
great surface that you can leave as is,
or paint, or anodized. While it's better
to debur before bead blasting, the glass
beads do have enough force that they can
remove small burs. Wile little to no
material is removed from the surface,
glass beads do peen the surface.
This is a fly cut aluminum surface
magnified 45 times. This is similar surface
after being bead blasted. I don't have
a method to measure surface roughness. The
bead blasted surface is rougher, it's
grippier, and it's uniform with reduced
machining marks.
While it's subjective and a personal
choice, I really like the appearance of a bead
blasted surface.
In general I really like sandblasting
old stuff because you restore that old
luster that's been lost.
Here's an old brass ornamental I used to
use on a Tesla coil. After bead blasting, the
corrosion is removed and the metal is left
untouched.
Here's a softer metal, a bit of copper and
well bead blasting did smooth the surface
slightly, it mainly only improved the
luster. All the ventilation parts are
made from ABS and I wondered how it
would stand up to bead blasting. The crude
has been removed and even with the nozzle
pointed directly at the plastic, the plastic
wasn't damaged. The gun of a sand blaster is the most important part.
Since not all of them are constructed the same way, I'd like to show you how this is
constructed so that you have some reference
when comparing other units. This gun separates into
four pieces: the handle, this barrel
assembly, a nozzle and a orifice. It's not
terribly easy to separate the barrel off.
I want to do this to show the size difference
between the orifice that it came with and talk a
little about the CFM requirements each
of them had. Here's the barrel completely
separate from the handle. Here's the nozzle,
barrel, and then the orifice inside. Just
pulled that out. A couple of the o-rings that
are on the orifice. This one came with two
orifices: this smaller diameter one, the
hole is smaller, and then a larger
one.
The larger size orifice is 1/8 inch
diameter. The smaller orifice is 5/64
inch. According to the tables that I
found, the 1/8 inch orifice should be
fine for
5 CFM but with the California Air Tools
compressor, this orifice would quickly
empty the tank. The 5/64 inch orifice works
pretty well with the California Air Tools
5pm compressor, it could probably be a
little bit smaller and it would make the
compressor able to keep up with the air
requirements a little bit better. The nozzles
are the same. It came with two and for all
intents and purposes they are then the
same. There is some build-up you can see
inside here. And I think that's from water they got
into the airstream. To measure the
performance of the air compressor, we'll
measure the tank pressure during
blasting and then during recovery.
With the 5/64 inch orifice, the air compressor
is able to maintain the required CFM at
60 PSI. And while Ii do have doubts about
the charts that shows CFM requirements
for various orifices size, I also
suspect the California Air Tools may be
a little optimistic in their specs.
Regardless, for my needs, I'm very
satisfied with this combination of air
compressor and sand blaster. This is what
I use for a vacuum and dust collection
around the shop. It's a Fein vacuum
spelled F E I N from the German
manufacturer Fein Power Tools.
It's coupled to a small cyclonic dust
separator called a Dust Deputy from Oneida
Air Systems. The combination of the
Dust Deputy and the HEPA filter of the Fein
vacuum works well. The vacuums power can
be adjusted. When used with the blasting
cabinet, it's probably best to use the lowest
power setting. Too much suction will just
waste abrasive. These are clean glass beads
magnified 45 times. These are glass beads
extracted from the vacuum. They have
broke down slightly, and there is some
debris, but mainly this shows the power
setting of the vacuum is too high. Even
in the winter, with a small compressor, it's
still important to use water separator.
This is after probably 15 minutes of use.
If the water is not separated from the
airstream, it will cause the glass beads to
clump. This will clog the siphon tube and into
prevent uptake of the abrasive. It's
surprising how much static builds up
around the sand blasting cabinet and you may
consider grounding the grating inside
the cabinet. Nasty stickers can be removed
from the glass or plastic by soaking
them in vegetable oil. Let the oil work
on the adhesive for a day and then
you'll be able to remove the label.
Another improvement I'd like to make to this
blasting cabinet that I didn't have time for this
video is a sloping surface to help guide
abrasive material. A lot of abrasive
material gets caught on the ridge that
holds the grating in place. The solution
could be as simple as four pieces of
wood cut at a bevel. Seeing how
important the right orifice size was for a
sandblaster to be used on a smaller
compressor, got me thinking about
alternative orifice and the nozzle designs.
The abrasive is accelerated in the
airstream and the higher the velocity of
the air stream or the longer
the period that the abrasive has to
accelerate, the abrasive will have a
higher exit velocity from the nozzle. The
force of the abrasive onto the surface
will be related to the square of the
velocity of the abrasive. I have been
simulating various orifices and nozzle
design. In particular de Laval or
convergent-divergent nozzles. Most
recommendations are to avoid abrasive
blasting unless you have a larger
compressor. I suspect that just a small
amount of optimization of the gun design
could improve the efficacy of small
compressors for abrasive blasting. If you
have any ideas or like to collaborate, as
always please let me know.
I hope that you found this video useful. Please send any
comments or suggestions you have and
finally I hope you'll be back to the next video.