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An air compressor is a vital
piece of equipment for abrasive glass etching. It is important to
select a good one for your use, as it can save you a lot of money
in the long run. If you pick the wrong one, you will probably have
to replace it in a short time and it probably won't do the job you
need for efficient etching.
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This
is a typical light duty, stationary piston compressor with upright
tank, about 4 1/2 feet tall. Stationary compressors are generally
best, because portable compressors usually provide too little
air for continuous blasting. |
Here
are some basic considerations in selecting a compressor for your
glass etching equipment
It doesn't
matter what kind of blasting equipment you have, an air compressor
is necessary to provide the power for the blaster. The air
output of the compressor in cubic feet per minute (CFM)
at a given pressure (PSI or pounds of pressure per square inch)
must be matched to the air consumption of the sandblaster
for the best efficiency. When looking at compressors, the air output
is usually stencilled on the compressor's air tank or it is printed
in the operating manual.
The air consumption
of any blaster can be figured from the air requirement chart on
the nozzle page. Find the nozzle size that comes
with the blaster. The chart will tell you how many CFM are required
for continuous blasting at a given pressure. Keep in mind that,
as you use the nozzle, the orifice will enlarge continuously, consuming
ever increasing amounts of air. When the nozzle enlarges to the
point where it is consuming more air than the compressor produces,
the compressor will run constantly, losing pressure and overheating
in the process. When the compressor runs almost continuously, it
is time to replace the nozzle in order to save wear on the compressor.
You may be tempted
to get a smaller, lower priced compressor in the beginning. This
may be OK when you are starting out as a hobbyist, but not for someone
wanting to work semi-professionally or professionally. A small compressor
may save money initially, but it will cost far more in wasted time
waiting for the compressor to catch up.
It will also cost more money on wasted nozzles. Most people doing
decorative sandblasting use 2HP to 5HP compressors and pressure
blasters with 3/32" nozzles. Using a 2HP compressor and silicon
carbide as an abrasive, a ceramic nozzle will enlarge to the point
where it needs to be replaced in about an hour. An industrial 5HP
compressor provides enough air so you could use the nozzle 2-3 hours.
If you only blast 5 hours per week, you would purchase 260 nozzles
in a year with the 2HP compressor or less than 130 with the 5HP
compressor. At approximately $3.25 per nozzle, the 5HP compressor
will save you at least $423 per year. Those savings alone would
pay off the extra cost of the larger compressor in a couple of years.
(Yes, carbide nozzles
last longer, but they cost more, too. So if you compare apples to
apples, the savings remain the same.)
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*Do
you need a Comprehensive Guide to selecting an air compressor?
There are many
other important considerations to selecting a compressor than we
can present here. Things like the difference between single stage
and two stage compressors or the difference between single phase
and three phase electricity for the compressor motor. Other considerations
include air tank size, type of lubrication for the compressor pump,
whether belt drive or direct drive is better, the service factor
of the electric motor, and more.
In addition,
we are only considering piston compressors here. Although these
are by far the most popular types of compressors, there are at least
4 other major categories of compressors. Other types of compressors
are built for heavy duty continuous use or for very quiet operation,
but generally cost much more.
This additional
information is not highly technical or difficult to understand and
we think you will be able to make a better decision if you know
it. To find out about this additional information you can do several
things:
- Take
one of our 4 day Professional seminars (compressor information
is included)
- Get
your glass etching equipment from us! No, we don't sell compressors,
but we do offer compressor assistance to all our equipment customers
- Wait
for our Guide to Selecting an Air Compressor
for Glass Etching. This is written for people who
are not technically oriented. It will be available by the end
of December.
- Consult
a local compressor specialist who may take the time to explain
all the details. Be careful because these folks will be trying
to sell you a compressor!
Learning
a little about compressors will be well worth your time and money!
(Some other
questions you may want to know: Would you only use an electric
compressor for glass etching? What about using a gas engine or
diesel compressor? What kind of compressor do you need for On-Site
blasting? What about an air compressor for micro blasting or airbrushing?
Should I order a compressor from a discount warehouse out of state
because the price is cheaper. . . )
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