By Jim Hingst
In shopping for an air
compressor, I am reminded of the advice of the Victorian writer, John Ruskin:
“It's unwise to pay too much but it's unwise to pay too little. When you pay
too much you lose a little money, that is all. When you pay too little, you
sometimes lose everything, because the thing you bought was incapable of doing
the thing you bought it to do.”
Make no mistake about it,
budgetary considerations are important. In today’s challenging economy, they
are more important than ever. But budget
is just one of many considerations. In this article, I will review these
considerations, which include compressor type, product specifications, such as
horsepower, portability, and most important factor of them all – its intended
use.
budgetary considerations are important. In today’s challenging economy, they
are more important than ever. But budget
is just one of many considerations. In this article, I will review these
considerations, which include compressor type, product specifications, such as
horsepower, portability, and most important factor of them all – its intended
use.
How an Air Compressor Works
I liken the way an air compressor
works to the way I pack my clothes into my suitcase. Imagine taking eight cubic
feet of clothing and forcing it into four cubic feet of space. Somehow I manage
to compress the clothes and batten down the latches.
works to the way I pack my clothes into my suitcase. Imagine taking eight cubic
feet of clothing and forcing it into four cubic feet of space. Somehow I manage
to compress the clothes and batten down the latches.
An air compressor does about
the same thing – just more efficiently. It takes a given volume of air; let’s
say eight cubic feet of air; and then it packs or compresses it into a much
smaller space, about one cubic feet. By compacting or compressing the air, the
compressor puts the air under pressure. Forcing the air into a space eight
times smaller increases or multiplies
normal air pressure, which is about 15 psi at sea level, by a factor eight to 120psi.
the same thing – just more efficiently. It takes a given volume of air; let’s
say eight cubic feet of air; and then it packs or compresses it into a much
smaller space, about one cubic feet. By compacting or compressing the air, the
compressor puts the air under pressure. Forcing the air into a space eight
times smaller increases or multiplies
normal air pressure, which is about 15 psi at sea level, by a factor eight to 120psi.
Types of Air Compressors
The mechanical design of air
compressors differs from one model to another. The basic types or styles of
compressors are piston compressors, which are also called reciprocating
compressors, diaphragm compressors, rotary screw compressors and centrifugal
compressors.
compressors differs from one model to another. The basic types or styles of
compressors are piston compressors, which are also called reciprocating
compressors, diaphragm compressors, rotary screw compressors and centrifugal
compressors.
Regardless of the design,
air compressors have the same basic functions. I learned to describe the operation of a compressor as
“suck, squeeze and blow”. I apologize if
this description conjures up some unsavory connotations, and offends anyone.
For me, it was a good way to remember how the equipment works. The compressor
sucks in air which is the intake phase; it squeezes the air in the compression
phase; and it blows out the air in the exhaust phase.
air compressors have the same basic functions. I learned to describe the operation of a compressor as
“suck, squeeze and blow”. I apologize if
this description conjures up some unsavory connotations, and offends anyone.
For me, it was a good way to remember how the equipment works. The compressor
sucks in air which is the intake phase; it squeezes the air in the compression
phase; and it blows out the air in the exhaust phase.
Reciprocating Air Compressors
A reciprocating compressor
is just a fancy name for a system that uses a piston to operate. As the piston
of the compressor moves back and forth it forces outside air inside the air
tank, without letting any of that air escape. As more and more air is forced
into the tank the air pressure rises. While there are many different models of
reciprocating compressor, they all operate using this basic piston principle.
is just a fancy name for a system that uses a piston to operate. As the piston
of the compressor moves back and forth it forces outside air inside the air
tank, without letting any of that air escape. As more and more air is forced
into the tank the air pressure rises. While there are many different models of
reciprocating compressor, they all operate using this basic piston principle.
One difference between
single and two stage compressors is the amount of pressure that they can
deliver. The maximum output in pound per
square inch or psi for a single stage compressor is about 100 psi. Two stage compressors can deliver much higher pressures.
single and two stage compressors is the amount of pressure that they can
deliver. The maximum output in pound per
square inch or psi for a single stage compressor is about 100 psi. Two stage compressors can deliver much higher pressures.
Reciprocating compressors uses
pistons to compressors. Some of these
compressors have only one piston. These are called single stage compressors.
Other reciprocating compressors have two pistons and are referred to as two
stage compressors.
pistons to compressors. Some of these
compressors have only one piston. These are called single stage compressors.
Other reciprocating compressors have two pistons and are referred to as two
stage compressors.
DeWalt 60 gallon 5 hp Two
Stage Air Compressor Features
Stage Air Compressor Features
● Delivers 15.5 SCFM @ 90
PSI and 15.7 SCFM @ 40 PSI
PSI and 15.7 SCFM @ 40 PSI
● Produces up to 175 PSI
● 230 volt; Requires 30 amp
breaker
breaker
DeWalt 80-Gallon Two-Stage Cast Iron Industrial Air Compressor
● Delivers maximum 21.2 CFM
(Cubic Feet Per Minute) at 175-PSI (Pressure Per Square Inches).
(Cubic Feet Per Minute) at 175-PSI (Pressure Per Square Inches).
● Cast iron construction
provides reliable performance.
provides reliable performance.
● Piston design improves
compression efficiency.
compression efficiency.
● 7.5 HP engine for industrial
performance can handle big jobs.
performance can handle big jobs.
● Sufficient power to
operate more than one air tool or device at one time.
operate more than one air tool or device at one time.
Oil Filters
Nobody wants in oil in their
paint or sandblast medium. That’s an
advantage of an oil-less airbrush compressor.
No oil! No contamination! No problems with fish eyes.
paint or sandblast medium. That’s an
advantage of an oil-less airbrush compressor.
No oil! No contamination! No problems with fish eyes.
If oil is such a bad thing,
why don’t they make all compressors oil-less?
Without oil, compressors run hotter. That contributes to the potential
water vapor problem in your air lines. It’s not the only problem, and certainly
not the most important one. Running a
compressor at higher temperatures shortens it useful life.
why don’t they make all compressors oil-less?
Without oil, compressors run hotter. That contributes to the potential
water vapor problem in your air lines. It’s not the only problem, and certainly
not the most important one. Running a
compressor at higher temperatures shortens it useful life.
If you buy a compressor that
is lubricated with oil, you will need an oil filter in addition to your water
filter. Just having a water film, just
won’t do. The oil filter traps any of
the oil that gets into your air line, before it gets to your airbrush or spray
gun.
is lubricated with oil, you will need an oil filter in addition to your water
filter. Just having a water film, just
won’t do. The oil filter traps any of
the oil that gets into your air line, before it gets to your airbrush or spray
gun.
PneumaticPlus Three Stage Air Drying System – Air Particulate Filter, 0.3 Micron Coalescing Filter & Air Pressure Regulator Modular Combo 3/8″ NPT – Manual Drain, Metal Bowl
● Removes dirt and foreign particles
and provides separation of moisture.
and provides separation of moisture.
● Filters 99.7 percentage of oil aerosols and microscopic
particles down to 0.3 micron.
particles down to 0.3 micron.
● High-performance regulator reduces primary pressure to a
desired pressure setting.
desired pressure setting.
● Manual Drain & Poly Bowl with Bowl Guard
● Includes 0-150 PSI Pressure Gauge & Bracket
● Max. Supply Pressure: 250 PSI, Max Operating Pressure: 150
PSI
PSI
Piston compressors come in
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
Two stage compressors are
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
For a small shop or a do-it-yourselfer
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
Reciprocating or piston-type
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
Piston compressors come in
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
Two stage compressors are
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
For a small shop or a do-it-yourselfer
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
Reciprocating or piston-type
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
Piston compressors come in
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
two varieties: those with just one piston, called single stage compressors; and
those with two pistons, called two stage compressors. Both types of compressors have air storage
tanks. Here’s how they work. The piston compresses the air and pushes it
into the storage tank. When the air pressure
attains a specified level, the compressor motor shuts off. This gives the motor a period of respite, so
it doesn’t overheat. After the pressure
drops below the specified level, the motor kicks in again and the piston pumps
up the air pressure in tank.
Two stage compressors are
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
typically more expensive. This type of equipment is designed for heavy-duty
commercial applications. If you need to
use a compressor continually, you need to seriously consider this type of unit.
For a small shop or a do-it-yourselfer
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
spraying in his garage, a reciprocating system is the most affordable and the
most common type of compressor. The key
questions, though, are: (1) will this style of compressor will provide you with
the capacity you need? (2) Will it provide you with the useful life that you
expect? (3) What will it cost to operate and maintain this type of compressor?
Reciprocating or piston-type
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
of compressors are not the only type on the market. If you will be using a compressed air on a
continuous basis, you will need a heavy-duty industrial unit, such as a rotary screw or centrifugal compressor.
Diaphragm compressors.
Diaphragm compressors work
similarly to reciprocating or piston compressors. Instead of a piston pumping back and forth
inside of a cylinder to compress the air, a diaphragm compressor uses a
membrane that pulses back and forth. Among airbrush artists, diaphragm
compressors are a popular choice, especially among novices, because they are
relatively inexpensive. In physical size, these compressors are very compact
and lightweight, which makes them very portable. This is perfect for the artist on the move,
who must go to the job site versus doing the work in the comfort of his shop.
similarly to reciprocating or piston compressors. Instead of a piston pumping back and forth
inside of a cylinder to compress the air, a diaphragm compressor uses a
membrane that pulses back and forth. Among airbrush artists, diaphragm
compressors are a popular choice, especially among novices, because they are
relatively inexpensive. In physical size, these compressors are very compact
and lightweight, which makes them very portable. This is perfect for the artist on the move,
who must go to the job site versus doing the work in the comfort of his shop.
You get what you pay for,
though. Diaphragm compressors are noisy. They usually don’t have an air storage
tank, which means they are running all of the time. Not only are you subjected to constant
noise, but because they are working all of the time, they run hot. The hot air that they pump is loaded with moisture
vapor that can make its way to your airbrush. The length of time that you can
use this type of compressor is limited, because it can overheat, which will
also shorten the unit’s lifetime use.
Diaphragm compressors also have insufficient power to deliver the volume
of air at the air pressure required to operate anything more than a single
airbrush.
though. Diaphragm compressors are noisy. They usually don’t have an air storage
tank, which means they are running all of the time. Not only are you subjected to constant
noise, but because they are working all of the time, they run hot. The hot air that they pump is loaded with moisture
vapor that can make its way to your airbrush. The length of time that you can
use this type of compressor is limited, because it can overheat, which will
also shorten the unit’s lifetime use.
Diaphragm compressors also have insufficient power to deliver the volume
of air at the air pressure required to operate anything more than a single
airbrush.
Rotary Screw Compressors.
Instead of using a piston to
compress air, a rotary screw compressor uses a rotor inside of a casing. The mechanism of a rotary compressors is
encased or surrounded by oil.
(Water-cooled units are also available.) The oil serves two
functions. First, it cools the air. This
cooling significantly reduces the problems associated with water vapor.
Secondly, cooling compresses the air.
compress air, a rotary screw compressor uses a rotor inside of a casing. The mechanism of a rotary compressors is
encased or surrounded by oil.
(Water-cooled units are also available.) The oil serves two
functions. First, it cools the air. This
cooling significantly reduces the problems associated with water vapor.
Secondly, cooling compresses the air.
Because rotary screw
compressors do not have a pumping mechanism
like a piston type of compressor, the air pressure is constant rather
than pulsing.
compressors do not have a pumping mechanism
like a piston type of compressor, the air pressure is constant rather
than pulsing.
Although this type of
compressor is often used for industrial applications, the physical size of the
unit is not necessarily massive. Instead, these compressors are typically
compact and can deliver a high volume of air at high pressure. If maintained
properly, these units will provide years of service.
compressor is often used for industrial applications, the physical size of the
unit is not necessarily massive. Instead, these compressors are typically
compact and can deliver a high volume of air at high pressure. If maintained
properly, these units will provide years of service.
Centrifugal Compressors.
Centrifugal compressors use
a centrifuge to compress air. A spinning blade rotates on a shaft to suck air
into the compressor, where it is compressed and discharged. Unlike a reciprocating compressor, which uses
the pulsing motion of a piston, a centrifugal compressor delivers a steady
stream of air. This high capacity
equipment is designed for industrial applications, rather than for shop
use.
a centrifuge to compress air. A spinning blade rotates on a shaft to suck air
into the compressor, where it is compressed and discharged. Unlike a reciprocating compressor, which uses
the pulsing motion of a piston, a centrifugal compressor delivers a steady
stream of air. This high capacity
equipment is designed for industrial applications, rather than for shop
use.
Other Parts Of The System.
In addition to the
compressor, the other elements of the air supply system that you will need to
consider and in some cases budget for include the storage tank, air hoses and
piping, air regulators and gauges, and filters. Many shops use some type of
piston compressor. In the plumbing for
the system, you will need to allow for an air pressure regulator at each drop,
a moisture filter, an oil filter and shut off valves.
compressor, the other elements of the air supply system that you will need to
consider and in some cases budget for include the storage tank, air hoses and
piping, air regulators and gauges, and filters. Many shops use some type of
piston compressor. In the plumbing for
the system, you will need to allow for an air pressure regulator at each drop,
a moisture filter, an oil filter and shut off valves.
Air Compressor Storage Tank.
If you buy a reciprocating
or piston type of compressor, it will probably have an air storage tank. This
storage or receiver tank provides a number of different functions. Storing
pressurized air is the key function. By
doing this, the storage tank is similar to a capacitor in an electrical system.
The stored air provides a constant flow of air, eliminating fluctuations in air
pressure.
or piston type of compressor, it will probably have an air storage tank. This
storage or receiver tank provides a number of different functions. Storing
pressurized air is the key function. By
doing this, the storage tank is similar to a capacitor in an electrical system.
The stored air provides a constant flow of air, eliminating fluctuations in air
pressure.
“If you invest in a
compressor, buy one with a storage tank,” says Julian Braet of Mr. J’s Sign
Service in Paterson, NJ. “Without a
tank, you can’t regulate the air pressure,” he says. “The pressure ebbs and
flows with the pulsing of the piston.”
compressor, buy one with a storage tank,” says Julian Braet of Mr. J’s Sign
Service in Paterson, NJ. “Without a
tank, you can’t regulate the air pressure,” he says. “The pressure ebbs and
flows with the pulsing of the piston.”
In purchasing a system,
bigger the storage tank, the better, because the bigger the tank is, the more
compressed air it can store at higher air pressures. The size of storage tanks is rated in
gallons.
bigger the storage tank, the better, because the bigger the tank is, the more
compressed air it can store at higher air pressures. The size of storage tanks is rated in
gallons.
Just so you’re not confused,
the air tank of a compressor is also referred to as a reservoir or a receiver.
In selecting a compressor, pay attention to the size of the air tank. As the
horsepower and the CFM of the compressor
increases, so will the air tank increase correspondingly or at least it should. Generally, for every CFM of output capacity,
you will need a gallon of air tank space.
the air tank of a compressor is also referred to as a reservoir or a receiver.
In selecting a compressor, pay attention to the size of the air tank. As the
horsepower and the CFM of the compressor
increases, so will the air tank increase correspondingly or at least it should. Generally, for every CFM of output capacity,
you will need a gallon of air tank space.
The purpose of a storage
tank is to supply you with an uninterrupted supply of air at a constant air
pressure. If you are spray painting, the air stored in the tank prevents any
peaks and valleys in the amount of air that your spray gun is supplied, so it
functions properly.
tank is to supply you with an uninterrupted supply of air at a constant air
pressure. If you are spray painting, the air stored in the tank prevents any
peaks and valleys in the amount of air that your spray gun is supplied, so it
functions properly.
The air tank functions as a
holding tank of compressed air. It also performs another function. In this
storage tank, the moisture-laden air cools down. As it does, the moisture
condenses and water forms at the bottom of the tank. For this reason, you should periodically
drain the air tank, which will help keep water out of the air lines.
holding tank of compressed air. It also performs another function. In this
storage tank, the moisture-laden air cools down. As it does, the moisture
condenses and water forms at the bottom of the tank. For this reason, you should periodically
drain the air tank, which will help keep water out of the air lines.
Air regulator.
The purpose of the air
regulator is to reduce the air pressure from the compressor to a specified
amount. A good quality air regulator
with a pressure gauge on the outlet side is a must. Just so there is no mistake, there is an
inlet side for unregulated air and an outlet side after the air pressure has
been regulated. These ports are not
interchangeable. So that you don’t install the regulator the wrong way in the
line, they usually have an air on the body of the unit indicating the direction
of air flow.
regulator is to reduce the air pressure from the compressor to a specified
amount. A good quality air regulator
with a pressure gauge on the outlet side is a must. Just so there is no mistake, there is an
inlet side for unregulated air and an outlet side after the air pressure has
been regulated. These ports are not
interchangeable. So that you don’t install the regulator the wrong way in the
line, they usually have an air on the body of the unit indicating the direction
of air flow.
Air Filters.
The air compressor isn’t just
compressing air; it’s also compressing and condensing the moisture in the air.
On a humid day, that’s a lot of water. If you’re sweating bullets in your shop,
just think about what’s happening inside your compressor. When the ambient temperature is hot and the
humidity is high, your compressor can produce gallons of moisture. The hot air
exhausted from the compressor is also saturated with water vapor. As the air
travels through an air line or , the hot air cools, condenses and forms droplets of moisture inside the
pipe.
compressing air; it’s also compressing and condensing the moisture in the air.
On a humid day, that’s a lot of water. If you’re sweating bullets in your shop,
just think about what’s happening inside your compressor. When the ambient temperature is hot and the
humidity is high, your compressor can produce gallons of moisture. The hot air
exhausted from the compressor is also saturated with water vapor. As the air
travels through an air line or , the hot air cools, condenses and forms droplets of moisture inside the
pipe.
Along with water, the compressed
air may also have picked up other contaminants, such as particles of rust and
dirt. All of these contaminants can clog your spray gun or screw up your paint
job. To prevent contaminant-related problems your compressed air system needs
filters. Here’s how filters work. The air enters the inlet; it goes ‘round and
‘round, bouncing up against the walls of the filter, causing the water and
other contaminants to flow to the bottom of the filter bowl. The purified air
is then expelled through the outlet.
air may also have picked up other contaminants, such as particles of rust and
dirt. All of these contaminants can clog your spray gun or screw up your paint
job. To prevent contaminant-related problems your compressed air system needs
filters. Here’s how filters work. The air enters the inlet; it goes ‘round and
‘round, bouncing up against the walls of the filter, causing the water and
other contaminants to flow to the bottom of the filter bowl. The purified air
is then expelled through the outlet.
Green Side Up.
You have probably heard the
joke about the dumb landscapers that needed to be reminded when laying sod:
“green side up”. When installing an air
filter there’s only one way to do it right. Pay attention to the arrow, usually
marked on the cap of the filter or on the body of the unit. The arrow indicates
the direction of the air flow. If you install the filter backwards, it will not
work properly.
joke about the dumb landscapers that needed to be reminded when laying sod:
“green side up”. When installing an air
filter there’s only one way to do it right. Pay attention to the arrow, usually
marked on the cap of the filter or on the body of the unit. The arrow indicates
the direction of the air flow. If you install the filter backwards, it will not
work properly.
Air filters comes in various
sizes. Here’s another rule about air
filters: “size matters”. In selecting an air filter for your system, make sure
that you install one that is big enough to handle the volume of air that your
compressor can generate. If you don’t you will restrict the flow of air, decreasing its volume and pressure downstream
after the filter. Don’t worry about installing an air filter larger than what
you really need. It won’t hurt anything.
sizes. Here’s another rule about air
filters: “size matters”. In selecting an air filter for your system, make sure
that you install one that is big enough to handle the volume of air that your
compressor can generate. If you don’t you will restrict the flow of air, decreasing its volume and pressure downstream
after the filter. Don’t worry about installing an air filter larger than what
you really need. It won’t hurt anything.
As the filter element inside
the filter separates the contaminants from the air stream, it gradually fills
up with waste matter at the bottom of the bowl.
the filter separates the contaminants from the air stream, it gradually fills
up with waste matter at the bottom of the bowl.
This debris must be drained
regularly or it will become clogged with contaminants. The drain for the filter is a little valve at
the base of the bowl. Periodically the filter will need to be replaced.
regularly or it will become clogged with contaminants. The drain for the filter is a little valve at
the base of the bowl. Periodically the filter will need to be replaced.
Just as the filters in your
car can become clogged with contaminants, the same can happen with the filter
element in your air filter. Maintenance of air filters includes replacing
filter elements.
car can become clogged with contaminants, the same can happen with the filter
element in your air filter. Maintenance of air filters includes replacing
filter elements.
In the bowl surrounding the
filter elements, debris consisting of water and oil, will collect at the bottom
of the filter. As this waste material collects, it should be drained using the
valve at the bottom of the bowl. This
gunk is considered “hazardous waste”. You should dispose of it according to
local regulations.
filter elements, debris consisting of water and oil, will collect at the bottom
of the filter. As this waste material collects, it should be drained using the
valve at the bottom of the bowl. This
gunk is considered “hazardous waste”. You should dispose of it according to
local regulations.
Pipes and hoses.
Air from the compressor is
hot and quite often is laden with lots of water vapor. A water filter is designed to trap water in a
liquid state. It won’t, however, trap
water vapor. This moisture can pass through the filter and end up in your
paint, causing problems.
hot and quite often is laden with lots of water vapor. A water filter is designed to trap water in a
liquid state. It won’t, however, trap
water vapor. This moisture can pass through the filter and end up in your
paint, causing problems.
So how do you solve this
dilemma? To trap the moisture, the hot
air needs to chill out and condense as droplets. One way to do that is to use at least 25 feet
of hose from your compressor to your
water and oil filter. As an alternative to hosing, some people prefer to use
metal piping for a neater installation.
To further trap any moisture in the line, you can also include a riser
and drain valve in the plumbing before the water separator.
dilemma? To trap the moisture, the hot
air needs to chill out and condense as droplets. One way to do that is to use at least 25 feet
of hose from your compressor to your
water and oil filter. As an alternative to hosing, some people prefer to use
metal piping for a neater installation.
To further trap any moisture in the line, you can also include a riser
and drain valve in the plumbing before the water separator.
Purchasing Considerations.
How do you select the right
for your shop? You certainly don’t want
to buy more compressor than you need. But then again, you don’t want to buy too
little of one either and put yourself in a position of having to upgrade a year
from now.
for your shop? You certainly don’t want
to buy more compressor than you need. But then again, you don’t want to buy too
little of one either and put yourself in a position of having to upgrade a year
from now.
In selecting a compressor
the primary consideration is having sufficient equipment capacity to satisfy
your shop requirements. What capacity
amounts to the ability of the compressor to supply the amount of air
that you need at the required pressure.
the primary consideration is having sufficient equipment capacity to satisfy
your shop requirements. What capacity
amounts to the ability of the compressor to supply the amount of air
that you need at the required pressure.
If you are shopping for a
compressor, bigger is better. Even if you don’t need maximum capacity that an
industrial compressor can produce, you can always dial down the air pressure.
compressor, bigger is better. Even if you don’t need maximum capacity that an
industrial compressor can produce, you can always dial down the air pressure.
Any other considerations,
while they may be important, are secondary. Some of these other considerations
include equipment cost, operating expenses, maintenance requirements, physical
size and noise level.
while they may be important, are secondary. Some of these other considerations
include equipment cost, operating expenses, maintenance requirements, physical
size and noise level.
When you compare the specs
for one compressor with another, be sure that you are comparing apples to
apples. Here are some factors to consider:
for one compressor with another, be sure that you are comparing apples to
apples. Here are some factors to consider:
Horsepower (hp). We rate the power of our car engines based
on horsepower, so why not rate compressors on the same standard? Don’t buy a
compressor solely based on its horsepower rating. In the grand scheme of things, the horsepower
of a compressor is not quite as important as you may think. It just refers to the power of the electric
motor. What is much more important is the output of the compressor in cubic
feet per minute or CFM at a specified pressure per square inch or psi.
on horsepower, so why not rate compressors on the same standard? Don’t buy a
compressor solely based on its horsepower rating. In the grand scheme of things, the horsepower
of a compressor is not quite as important as you may think. It just refers to the power of the electric
motor. What is much more important is the output of the compressor in cubic
feet per minute or CFM at a specified pressure per square inch or psi.
If you are running a
commercial sign shop, 10hp is ideal. You might be able to get by with a 5hp
unit, but if you can afford it, go with the bigger model. As a general rule of thumb, compressors with
a higher horsepower (hp) rating usually deliver higher psi. Another rule of
thumb is that 1 hp will deliver 4 cfm at 90 psi.
commercial sign shop, 10hp is ideal. You might be able to get by with a 5hp
unit, but if you can afford it, go with the bigger model. As a general rule of thumb, compressors with
a higher horsepower (hp) rating usually deliver higher psi. Another rule of
thumb is that 1 hp will deliver 4 cfm at 90 psi.
Pressure Per Square Inch
(psi). Air pressure is measured in pounds per square inch. It is critical, because the more viscous or
thicker a paint is, the more pressure is required for airbrushing. Thin or low
viscosity paints, can be sprayed at low pressures, such as 30 psi. Other paints, such as some water based
paints, require pressures as high as 50 to 60 psi.
(psi). Air pressure is measured in pounds per square inch. It is critical, because the more viscous or
thicker a paint is, the more pressure is required for airbrushing. Thin or low
viscosity paints, can be sprayed at low pressures, such as 30 psi. Other paints, such as some water based
paints, require pressures as high as 50 to 60 psi.
Cubic Feet Per Minute (CFM).
The amount of air pressure that an air compressor produces is just one way to
compare or rate a system. But it’s not
the only way and certainly not the best.
The amount of air pressure that an air compressor produces is just one way to
compare or rate a system. But it’s not
the only way and certainly not the best.
Here’s one reason. When
spray painting or sandblasting, air pressure is not enough, if your air compressor
cannot produce the required volume of air required. A more useful standard for
gauging the performance of a compressor is cubic feet per minute or CFM. CFM is
a measurement of how much air, in cubic
feet, that the compressor displaces or discharges per minute.
spray painting or sandblasting, air pressure is not enough, if your air compressor
cannot produce the required volume of air required. A more useful standard for
gauging the performance of a compressor is cubic feet per minute or CFM. CFM is
a measurement of how much air, in cubic
feet, that the compressor displaces or discharges per minute.
For the large industrial
compressors, 10HP and larger, you can figure that 1HP will produce 4CFM @
90PSI. That’s a great rule of thumb, but
it doesn’t do you much good if you are buying a smaller compressor. In these
cases, the rule of thumb is forget the rule of thumb and study the specs.
compressors, 10HP and larger, you can figure that 1HP will produce 4CFM @
90PSI. That’s a great rule of thumb, but
it doesn’t do you much good if you are buying a smaller compressor. In these
cases, the rule of thumb is forget the rule of thumb and study the specs.
Noise. Most compressors are
noisy. Really noisy. Thirty years ago I
built a studio adjacent to a large compressor. Even though the walls were
soundproofed, I could still heard the muffled sound of the compressor every
time it kicked in. This is especially
distracting for some airbrush artists, when they are trying to concentrate on
their work.
noisy. Really noisy. Thirty years ago I
built a studio adjacent to a large compressor. Even though the walls were
soundproofed, I could still heard the muffled sound of the compressor every
time it kicked in. This is especially
distracting for some airbrush artists, when they are trying to concentrate on
their work.
For Airbrush Artists:
Iwata-Medea Studio Series Power Jet Pro Double Piston Air Compressor
●
Powerful twin-pump, 1/6 HP motor.
Powerful twin-pump, 1/6 HP motor.
●
Produces full-capacity air on demand.
Produces full-capacity air on demand.
●
Two air pressure regulators for precise adjustment of airflow at two individual
workstations.
Two air pressure regulators for precise adjustment of airflow at two individual
workstations.
●
Automatically shuts off when not in use.
Automatically shuts off when not in use.
●
Economically priced.
Economically priced.
●
2 liter tank air storage tank.
2 liter tank air storage tank.
●
Less heat-relatezd moisture build-up.
Less heat-relatezd moisture build-up.
●
Features quieter operation.
Features quieter operation.
For those who cherish peace
and quiet, especially those that work out of their homes, you have a few
options. You can buy a quiet airbrush compressor, such as those sold by
Silentaire. Or you can decide not to use
a compressor and instead use cylinders
of CO2.
and quiet, especially those that work out of their homes, you have a few
options. You can buy a quiet airbrush compressor, such as those sold by
Silentaire. Or you can decide not to use
a compressor and instead use cylinders
of CO2.
“You don’t have to buy the
CO2 tank,” says Julian “Mr. J” Braet.
“You just lease the tank and pay for the refills.” Tanks come in different sizes, such as 20lb.
and 40lb.
CO2 tank,” says Julian “Mr. J” Braet.
“You just lease the tank and pay for the refills.” Tanks come in different sizes, such as 20lb.
and 40lb.
Finally, you could locate the
compressor in a room some distance from the one where you work. Each of these
options is viable. The one that is best for you, depends on your own
requirements.
compressor in a room some distance from the one where you work. Each of these
options is viable. The one that is best for you, depends on your own
requirements.
Mr. J has his compressor in
another building. That way he isn’t
distracted when the compressor kicks in.
In running air lines, he recommends running ½” pipe.
another building. That way he isn’t
distracted when the compressor kicks in.
In running air lines, he recommends running ½” pipe.
Portability.
If the job won’t come to
you, and you must go to the job, you will need a portable unit that you can
throw in the back of your truck.
you, and you must go to the job, you will need a portable unit that you can
throw in the back of your truck.
Future Air Compressor
Needs.
Before you make an
investment in equipment, remember to gaze into your crystal ball and envision
what the future may bring. If your
business grows according to your plans, make sure that the compressor that you
buy today, satisfies your needs three years from now or five years from now.
investment in equipment, remember to gaze into your crystal ball and envision
what the future may bring. If your
business grows according to your plans, make sure that the compressor that you
buy today, satisfies your needs three years from now or five years from now.
In deciding on the size of
compressor that you will need for your shop, you need to consider your
requirements today and in the near future. Operating a single spray gun is not
a very demanding application, because typical requirements are only 5 to
10CFM. If you need to operate several
spray guns, your requirements have multiplied.
compressor that you will need for your shop, you need to consider your
requirements today and in the near future. Operating a single spray gun is not
a very demanding application, because typical requirements are only 5 to
10CFM. If you need to operate several
spray guns, your requirements have multiplied.
In determining the right
size of compressor for your shop, make a list of the tools that you will run
with compressed air. Next to each tool,
write down how much CFM the tool will require. Then tally up the numbers. In
determining air consumption for a specific tool, you may need to get the
information from the manufacturer, because air consumption can vary from one
model to another.
size of compressor for your shop, make a list of the tools that you will run
with compressed air. Next to each tool,
write down how much CFM the tool will require. Then tally up the numbers. In
determining air consumption for a specific tool, you may need to get the
information from the manufacturer, because air consumption can vary from one
model to another.
After you determine what you
will need, factor in a little extra. You will need at least another 10%
additional capacity to compensate for pressure drop and air leaks.
will need, factor in a little extra. You will need at least another 10%
additional capacity to compensate for pressure drop and air leaks.
Budget.
When buying a compressor,
you need to look beyond the price tags. Resign yourself to the reality that you
are going to have to spend at the very least more than $750. For that amount of money, you can buy a 5 to
6 HP compressor, producing about 12CFM at 100psi, with a 60 gallon storage
tank. A compressor such as this will provide you with the minimum amount of
capacity to run a spray gun.
you need to look beyond the price tags. Resign yourself to the reality that you
are going to have to spend at the very least more than $750. For that amount of money, you can buy a 5 to
6 HP compressor, producing about 12CFM at 100psi, with a 60 gallon storage
tank. A compressor such as this will provide you with the minimum amount of
capacity to run a spray gun.
If your needs exceed this,
you will have to take the next step up. A compressor that can deliver 15CFM at
100psi with a storage capacity of 80 gallons will cost at least $1,200 to
$1,500. This should be enough compressor
for a small shop. Anything less and you are asking for trouble. Either the
compressor won’t have capacity you need or it will wear out or burn up within a
year or two. In the end, if you buy a cheap, you will get what you pay for and
you will probably need to buy another compressor. By that time, maybe you will
buy the unit that you should have bought in the first place.
you will have to take the next step up. A compressor that can deliver 15CFM at
100psi with a storage capacity of 80 gallons will cost at least $1,200 to
$1,500. This should be enough compressor
for a small shop. Anything less and you are asking for trouble. Either the
compressor won’t have capacity you need or it will wear out or burn up within a
year or two. In the end, if you buy a cheap, you will get what you pay for and
you will probably need to buy another compressor. By that time, maybe you will
buy the unit that you should have bought in the first place.
Airbrushing And Spray
Painting.
If you are a novice airbrush
artist, there’s nothing wrong with a small compressor. You can buy a 1/5 hp or
1/8 hp oil-less unit for about $250.
artist, there’s nothing wrong with a small compressor. You can buy a 1/5 hp or
1/8 hp oil-less unit for about $250.
Don’t get the idea that
you’ll can also spray paint cars with a small compressor. Spray guns and air tools require more
capacity, which is measured not just in air pressure, but more importantly is
rated in terms of how many cubic feet per minute (CFM) a compressor can crank
out.
you’ll can also spray paint cars with a small compressor. Spray guns and air tools require more
capacity, which is measured not just in air pressure, but more importantly is
rated in terms of how many cubic feet per minute (CFM) a compressor can crank
out.
Special Requirements for
Sandblasting.
In selecting a compressor
for sandblasting equipment, always buy a compressor that exceeds equipment
requirements by 25% to 30%. For etching
and carving glass or wood, you will typically need a compressor that can
deliver 5 to 10 CFM @ 30 psi. Frugality
does not pay off in this area. Pricking
an underpowered compressor can result in two problems. The first is that you may not reach the blast
pressure required. And the second
problem is that you overwork the compressor and it prematurely fails.
for sandblasting equipment, always buy a compressor that exceeds equipment
requirements by 25% to 30%. For etching
and carving glass or wood, you will typically need a compressor that can
deliver 5 to 10 CFM @ 30 psi. Frugality
does not pay off in this area. Pricking
an underpowered compressor can result in two problems. The first is that you may not reach the blast
pressure required. And the second
problem is that you overwork the compressor and it prematurely fails.
In selecting the compressor,
you will need to consider to key factors: pressure (measured in pound per
square foot or psi) and volume (measured in cubic feet per minute or cfm). In
buying a compressor, also consider all of the different possible uses for this
equipment, such as spray painting, sandblasting and air powered tools.
you will need to consider to key factors: pressure (measured in pound per
square foot or psi) and volume (measured in cubic feet per minute or cfm). In
buying a compressor, also consider all of the different possible uses for this
equipment, such as spray painting, sandblasting and air powered tools.
For a standard pressure
blaster, you will need a compressor with an output of at least 5 cfm at 40 psi.
Pressure blasters aren’t the only type of sandblast equipment on the
market. A much cheaper option is to buy
a siphon blaster. If you buy a siphon
blaster, you will need a compressor with a higher capacity. What you save in the cost of the blaster,
will require a more costly investment in a compressor.
blaster, you will need a compressor with an output of at least 5 cfm at 40 psi.
Pressure blasters aren’t the only type of sandblast equipment on the
market. A much cheaper option is to buy
a siphon blaster. If you buy a siphon
blaster, you will need a compressor with a higher capacity. What you save in the cost of the blaster,
will require a more costly investment in a compressor.
To operate a pressure
blaster you will need at least a 5 hp compressor; a siphon compressor requires
a 10 hp compressor with an output of 38cfm @ 80psi.
blaster you will need at least a 5 hp compressor; a siphon compressor requires
a 10 hp compressor with an output of 38cfm @ 80psi.
Sandblast specialist, Linda
Roederer (also known as “that blasted glass girl”) believes that investing in a
pressure pot blaster as well as the big compressor is the way to go. “Don’t skimp on the compressor,” she says.
“It’s really exasperating to have to wait on air when you’re working on a
larger piece.”
Roederer (also known as “that blasted glass girl”) believes that investing in a
pressure pot blaster as well as the big compressor is the way to go. “Don’t skimp on the compressor,” she says.
“It’s really exasperating to have to wait on air when you’re working on a
larger piece.”
“When I am carving large
pieces of glass, I need lots of pressure,” Roederer says. “In many cases, I am
using 80 psi to frost a large architectural piece.”
pieces of glass, I need lots of pressure,” Roederer says. “In many cases, I am
using 80 psi to frost a large architectural piece.”
After you decide on a
compressor, you will also need a good filtering system, so the air supplied to
the blaster is clean and dry. Why is that important? Moisture in your air will
cause the dust to clog filters.
compressor, you will also need a good filtering system, so the air supplied to
the blaster is clean and dry. Why is that important? Moisture in your air will
cause the dust to clog filters.
“I have a moisture separator
at the tank and at the pressure pot to ensure that I don’t end up blasting with
wet abrasive,” says Roederer.
at the tank and at the pressure pot to ensure that I don’t end up blasting with
wet abrasive,” says Roederer.
Compressor Maintenance.
Do you remember the TV
commercial in which an auto mechanic proclaims, “you can pay me now, or pay me
later.” Just as regular maintenance is
critical for your car, it is equally important for your compressor. Failure to
follow the manufacturer’s preventative maintenance schedule can result in
equipment failure.
commercial in which an auto mechanic proclaims, “you can pay me now, or pay me
later.” Just as regular maintenance is
critical for your car, it is equally important for your compressor. Failure to
follow the manufacturer’s preventative maintenance schedule can result in
equipment failure.
Oil-free compressors, which
have sealed bearings, are virtually maintenance free. For most commercial applications, these compressors
are underpowered. To operate an
airbrush, though, this type of unit provides sufficient air.
have sealed bearings, are virtually maintenance free. For most commercial applications, these compressors
are underpowered. To operate an
airbrush, though, this type of unit provides sufficient air.
Compressors that are oil
lubricated require periodic maintenance. Like it or not, you need to study the
owner’s manual and religiously follow the manufacturer’s recommendations,
before you use the compressor and screw things up.
lubricated require periodic maintenance. Like it or not, you need to study the
owner’s manual and religiously follow the manufacturer’s recommendations,
before you use the compressor and screw things up.
Just as you need to
regularly change the oil in your car, you will have to do the same with an air
compressor. Running your compressor when the oil is low can result in the engine
overheating. This can damage the motor. Some compressor motors also have
filters, which should also be changed according to the manufacturer’s
instructions.
regularly change the oil in your car, you will have to do the same with an air
compressor. Running your compressor when the oil is low can result in the engine
overheating. This can damage the motor. Some compressor motors also have
filters, which should also be changed according to the manufacturer’s
instructions.
Conclusion.
The key to making the right
decision in buying an air compressor is to do your homework. Determine the needs of your business,
anticipate future needs, collect all of the appropriate technical information
and then analyze the specifications. Avoid the temptation to buy a lower price
used compressors. Compressors have a
life expectancy, which is determined by hours of use and how the unit was
maintained. Rather than buying the
previous owner’s problems, it’s usually better to invest in new equipment. A new compressor comes with fewer surprises
and a warranty in case of problems. Finally, if you have questions when making
your purchasing decision, don’t be afraid to ask your friends in the business
for advice.
decision in buying an air compressor is to do your homework. Determine the needs of your business,
anticipate future needs, collect all of the appropriate technical information
and then analyze the specifications. Avoid the temptation to buy a lower price
used compressors. Compressors have a
life expectancy, which is determined by hours of use and how the unit was
maintained. Rather than buying the
previous owner’s problems, it’s usually better to invest in new equipment. A new compressor comes with fewer surprises
and a warranty in case of problems. Finally, if you have questions when making
your purchasing decision, don’t be afraid to ask your friends in the business
for advice.
About Jim Hingst: Sign business authority on vehicle wraps, vinyl graphics, screen printing, marketing, sales, gold leaf, woodcarving and painting.
After fourteen years as Business Development Manager at RTape, Jim Hingst retired. He was involved in many facets of the company’s business, including marketing, sales, product development and technical service.
Hingst began his career 42 years ago in the graphic arts field creating and producing advertising and promotional materials for a large test equipment manufacturer. Working for offset printers, large format screen printers, vinyl film manufacturers, and application tape companies, his experience included estimating, production planning, purchasing and production art, as well as sales and marketing. In his capacity as a salesman, Hingst was recognized with numerous sales achievement awards.
Drawing on his experience in production and as graphics installation subcontractor, Hingst provided the industry with practical advice, publishing more than 150 articles for publications, such as Signs Canada, SignCraft, Signs of the Times, Screen Printing, Sign and Digital Graphics and Sign Builder Illustrated. He also posted more than 500 stories on his blog (hingstssignpost.blogspot.com). In 2007 Hingst’s book, Vinyl Sign Techniques, was published. Vinyl Sign Techniques is available at sign supply distributors and at Amazon.
© Jim Hingst 2018
