My love affair with compressed air started a number
of years ago when I got an entry level oil-less air
compressor for Christmas. Looking like a bloated red fire
hydrant lying on its side, it made a deafening noise while it crawled its
way to 125 PSI.
As the number of air tools in my shop increased, the demand for
stored compressed air followed. The tools drained air
from the tank faster than the littler compressor could
That noisy compressor was replaced with a quiet
brute; a 5 HP, vertical standing, two-stage pulley
driven reciprocating type unit sitting on top of an 80
Finally the *Custovation™ shop had serious
air pressure (PSI) with enough volume (CFM) to run any
tool attached short of a jack-hammer.
The compressor is the best shop investment ever.
keep the air supply at arm's reach, several hose connections
were added. In no time, it seemed the assortment of
hoses connected to the compressor was spinning a web of
their own. There had to be a better way.
The solution was a permanent hard-line connection
with terminations at various places in the shop and
second garage. With that in mind, the compressor unit
could be placed almost anywhere, keeping the noise away
from the work area.
It’s good practice to have at least one drop
connection fitted with a regulator / dryer. That way you
can adjust the tool pressure to spec.
One consideration is
corrosion; as the compressor builds up air pressure, it
squeezes out water vapor and that condenses inside the
line. Corrosion of the line is caused by water formed
from the compression process.
Copper is durable over time and ranks high for
cleanliness since it has no corrosion issues. However,
cost is high and takes a degree of skill to install. Later modification to the distribution lines is a bit
more difficult due to lack of tubing flexibility and
Black iron pipe is used in a lot of industrial
applications with high pressures. It’s likely to corrode
over time but has the lowest probability of tube
breakdown due to high internal pressure.
Pipe is costly
and requires a high degree of skill to install, namely
using a pipe threading outfit to cut threads on the pipe
ends. Later modification to the distribution lines is
PVC is the choice of most compressor do-it-yourselfers. Its main positives are low cost, easy to
assemble and modify and has no corrosion issues. Its
weakness is that it can fail if the pipe is hit smartly
while under pressure and the joints can fail if not
Failing means shattering and that
means plastic shrapnel, so don’t short-cut the assembly
technique and protect the tubing from impacts.
If you choose white PVC, be sure to use the heavy
wall tubing version. It is generally dated and marked
with 480 PSI maximum internal pressure. Use 1” diameter
tubing with nominal wall thickness of .118”.
Whether you have a compact portable compressor or a
400 pound V-twin behemoth, hard air-lines can clean up
your shop and add more enjoyment when using air tools. Besides, the sound of VRIPPPT, VRIPPT
will put a smile on your face!
is no advantage of one style over another, provided they
are quality made, the most popular style is the
industrial. Just make sure that the female coupler is
compatible with the male, an important factor in air
couplers and life as well.
Typical Compressed Air Hose Couplers
Ingersoll Rand "Simplair" Connectors.
Hose inside diameter plays a big role in proper air tool
operation. The smaller the hose inside diameter, less
air gets through the line.
Hose length is also a factor. As air is forced through the line, pressure decreases
the farther the air has to travel.
For example, a 3/8” internal diameter hose has over
two times the cross sectional area than a ¼” ID hose.
So a ¼” ID hose
will drop about 20 PSI in 20 ft at 15 CFM. The same
length with a 3/8” hose drops only 2.8 PSI.
Select a high grade 3/8” all-weather 300 PSI hose for
maximum air delivery and flexibility. PVC jacked hose is
very durable and abrasion resistant.
Use a ¼” hose only
for the shortest runs, like a short self-coiling hose
near the tank or 1’ main line.
Some Compressor Tips
Use a swivel whip-hose end on your main hose to add
maximum tool movement flexibility.
A ¼’ self-coiling air hose 25’ long, keeps the most
used portion of the hose out of the way but ready for
Add a drop of air tool oil each time you use the tool
to lube the internal turbine and more frequently if you
use the tool for long work periods.
If you are spray painting with an oil-less compressor
keep the unit away from the painting area. Oil-less
units are poorly filtered and overspray dust will ruin
the piston causing it to seize in the bore. Guess how I
When spray painting always use a disposable
water-separator attached to the gun air input to prevent
any water to enter the gun.
Place a piece of carpet under the compressor to keep
if from wandering off while running.
Nothing really dries the air in a compressor line.
It’s a matter of condensation so empty the tank water
drain, line drains and any filters often.
When making a transition from PVC to brass fittings
and quick connects, the PVC female fittings can crack
from over tightening, so tighten carefully. Use white
Teflon tape on the brass threads for a no-leak joint.
In a PCV system, close the tank ball valve when the
air system is not in use to take pressure off the lines.
Five Must-Have Air Tools
All these tools are extremely useful but they can be
dangerous if handled carelessly. Become familiar with
the tools operation and NEVER use these tools without
eye protection or when children are present.
I believe the guy who adapted the industrial air
compressor for the home mechanic is a marketing guru for
the air tool industry. He must have studied how the
razor blade companies marketed their products,
back-in-the-day. That marketing strategy was simple:
hook the customer on the handle design, give it away and
then charge for the replacement blades. GENIUS!
The point being, that after a motorhead
/ garage-mechanic / hobby dude buys a compressor, they will
always divert their path through the home improvement
store checking out the collection of air tools standing
proudly on display. Yup, when that happens, you’re
hooked. There’s no turning back. Once you’ve
had air you can’t go back!
3/8" Drive Butterfly Impact Wrench
The only tool that allows you to single handedly remove
nuts and bolts from rotating shafts and other parts like
fork leg sliders. The rapid high impact motion breaks
the fastener free without having to jam the piece to
High Speed Auto Body Saw
Makes cutting sheet metal, bolts and small metal stock a
breeze. Just remember to apply a bit of oil to the
¼” Straight-Line Die Grinder
Great for work needing abrasive bit, small wire or
synthetic wheel or polishing pad treatment.
Right Angle Die Grinder
When the guys at Orange County Choppers demonstrated the
versatility of this tool for grinding and sanding, the
market response was so strong, most places where sold
out for weeks. They were right.
3” Cut-off Tool With Blade Shield
Great for cutting through metal when a saw isn’t
practical and having a rough edge cut isn’t important. Throws off a lot of sparks so watch you don’t burn
After you spend your money on the above and have a few
bucks left, consider this tool. It’s a
production air tool suitable for repetitive tightening
operations, but it does come in handy. Makes a great sound but has limited use
since manual ratchets are a lot faster. It can be very
helpful though if you have arthritic hands.
*Custovation™ is a combination of customizing, and
renovation. Not a restoration, which means to bring back
to an original condition. Custovation has a more
specific meaning: CUSTOMIZE - to make or alter to
individual or personal specifications combined with
RENOVATION which is to restore to an earlier condition,
by repairing or remodeling.
PSI and CFM are two important terms that determine the
performance of a compressor.
Using the water hose analogy, PSI (Pounds per
Inch) is how strong the water comes out of the hose.
(Cubic Feet per Minute) is related to volume of water
coming out of the hose. So there can be high pressure at
low volume. A strong stream but it takes a long time to
fill a bucket because there is low water volume. The
opposite is high volume (large hose) and the bucket gets
filled quickly but there’s very low pressure.
In a compressor, high air pressure is desirable to
run the mini-turbines inside air tools but they are
voracious consumers of air, so the compressor must
deliver a lot of air (CFM) at the high pressure. Small
air tools need about 90 PSI at 6 CFM for the tool to be
Any compressor delivering 135 PSI at 9 CFM or
greater should be ok for most small air tools. When
shopping for air tools, note that some use air more efficiently
needing less CFM but they usually cost a bit more.
Want to Know More About Compressed Air?
Check out the
Sharpe Manufacturing, Inc. web site for
excellent information about compressed air systems
and shop air piping layouts.
Ingersoll Rand has many air compressors,
compressed air tools and more. Thanks also to
Ingersoll Rand for some of the photos used in this
Inexpensive air tools suitable for the home shop at
Compressors are available everywhere and big ones at
With This Link to the Motorcycle
Superstore and Support webBikeWorld
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From "R": "Very good
comprehensive article by Texas Joe.
After 27 years in the mills, mines,
& shipyards (all huge users of Compressed Air) I
have a slightly different take on the theory of the
design of Compressed Air (CA) piping & systems.
I am now working in a small shop with a large air
demand for big power hammers, air tools, plasma
cutters, paint booth, etc
I definitely agree with R.L. about PVC piping in
compressed gas service. One look at the 2/3
remainder of a 2" Schedule 80 PVC tee, (the other
1/3 was never found!) would convince anyone as to
it's dangers. I think PVC pipe in compressed
gas service should be treated as an explosion
waiting to happen!
For a home or small shop, I like
copper the best. Minor corrosion problems,
good heat radiating qualities & it's recyclable.
By that I mean it's frequently available from
residential house demolition contractors, usually
for about 1/10 to 1/2 of the price of new.
Type M is not as common around here, as it's only
used for LP heating water & LP gas connections.
Domestic water systems generally use Type L Copper
Pipe so it is the most plentiful. Pipe that's
straight is easier to install & certainly looks
better hanging on the shop wall. Plastic
domestic piping (all the different kinds) are not
rated for CA pressures.
Black iron pipe (not galvanized) may
be cheaper to buy but rusting both inside & outside
has to be kept in mind always. It is commonly
used for industrial CA systems due to cost in the
larger sizes. Keep installation time & costs
---(Refer to the drawing
"Basic Air Line
Layout" above for details) -- think of a CA
system as a water network, air cooling radiator, &
condensation removal machine. The air will
always be there but most of the long term operating
problems come from the water that gradually
condenses out from the hot compressed air as it
cools. So I design the whole system for both
air cooling & water drainage.
1. Lots & lots of water traps (drain
legs or boots) with drain cocks. The full pressure
working valve on every vertical drop should always
come horizontally off the leg (or side) of a tee in
the drop rather than just from a vertical coupling
at the bottom pointing down. The bottom
vertical run of the tee should have a short length
of pipe (maybe 6") below it to hold any condensate
(see the regulator/filter/dryers in the drawing
A (small) drain cock on the bottom
allows for (frequent) draining (blowing down).
The fittings called "full pressure" as shown above
will pass on any condensate to your tools.
2. Drops should come off the header
with a tee with leg vertical up so air can be picked
up leaving the water behind. They should never
come vertically downward from off the header. (see
the "Basic Air Line Layout drawing above for
3. Make the condensate drain lines
from the main receiver tank very easy & very
convenient to blow down. A lot of the heat of
compression is given up in here, generating lots of
condensate. Even take the blow down valve over
to the back door so it can be done at the same time
as the shop is locked up at the end of the day. 3/8"
pipe or larger should do the job (1/4" will do but
it just takes longer). Even hose will work.
Perhaps an exhaust muffler will be needed to stay
friends with the neighbours!
4. The drawing above calls for 1"
drop per 10' of run. Don't be afraid to make
it more than that.
5. In order to cool the air sooner &
reduce system condensate, the drop from the flex
hose/compressor up to the header could be made from
several runs of small pipe rather than one large
one. For instance, a 1" header could be fed
from 3 or 4 runs of 1/2" copper pipe. Water traps at
the bottom please. More heat can be removed quicker,
knocking out the condensate.
It's not rocket science but planning
ahead will make Compresses Air just a fact of life,
not an occasional pain in the butt!"
From "R.L.": "This article
includes a lot of good information, however I’d
strongly recommend against using PVC pipe for a
compressed air supply. I’m not alone in that
PVC was banned by OSHA in 1988 for
use in above-ground gas delivery systems, unless
it’s encased in a shatter-proof container (i.e.
another, larger pipe over it). Its
characteristics under pressure (and not) vary quite
widely depending on the temperature. For a
demonstration, place a length in a freezer overnight
and then hit it with a hammer.
See this citation (there are lots
from OSHA on PVC pipes and a
great discussion by various engineers.
The pressure rating of 480 PSI is
for non-compressible contents, such as water.
Compressible contents use a different rating system.
The problem isn’t the pressure rating, per se; it’s
the failure mode, which you allude to in the
article. PVC shatters instead of tearing like
copper, rubber or iron does. Plastic chunks
really suck to remove from beneath ones skin, or,
God forbid, eyes.
Yes, many people have used it, and
many people have never had a problem. But
then, many people ride without a helmet, too.
Copper (Type L is good and what I
have, M is too thin for this, K is great but
expensive and hard to find) and iron pipe are
excellent choices. There are air-pressure
rated nylon piping on the market, too, but they’re
kind of expensive. Quick-connect aluminum
systems are out there, too. Awesome, but
If cost is a big factor (when is it
not? :), the truly poor-mans method is to use rubber
or synthetic air compressor hose between drops,
attached to the wall with plastic conduit clamps.
Ugly and prone to water-pooling in the low spots,
but very functional and safe, as long as it’s
fastened at many points. Just make sure you
inspect it regularly for wear.
Personally, I’d save up and do it