Subject: Compressor Size/Type

From: Joe McSheffery <[email-masked]>
Date: Sun, 30 Mar 1997 20:36:38 -0600

Hi there!

  I am thinking about buying an Air Compressor and want to get some
ideas from people who have some experience.

  I plan to use the Compressor to power;
   * Finish Nailers/Tackers in the Workshop,
   * Impact Wrench and other Automotive Tools, and
   * Framing Nailer and Roofing Nailer when I put an addition on our
house.

What is the Minimum recommended Horsepower I will require ?

Which is better, the Newer Oilless type or the "OLDER" Oil in the sump
style?

THNX in advance Joe McSh

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From: [email-masked] (Paul Baker)
Date: Mon, 31 Mar 1997 15:47:23 -0500

Joe,
Forget horsepower.  Pay attention to cfm.  Heres how I suggest you decide
on the compressor you need:  Find the tool you want to use that has the
highest cfm requirement.  Multiply that requirement by 1.5 and find a
compressor capable of producing that much cfm at 100psi.  

Nothing you've listed requires alot of air, unless automotive tools
include sandblasters or dual action sanders.  If you want to use these
things regularily, your best bet is a 2 stage compressor 18+cfm at 100psi
with an 80 gal tank (roughly $800+).  Economically, you could probably get
by with a single stage 12-14 cfm on a 60 gal tank ($350+).  If you want a
compressor to last, stay away from aluminum pump components and get the
"older" oil sump style.  Easy way to identify compressor stage: 2 stage
pressure is regulated at 175psi, single stage is 125psi.

If you don't need the type of automotive tools I've described above, you
can get by with a portable unit.  But, you can have a stationary 60gal
upright single stage for roughly the same cost as a portable if you shop
around.  IMO the best buy, if you buy enough airhose to reach the roof.

Oh, and when shopping air hose for larger tools - you gotta buy large ID. 
On the order of 3/8 to 1/2 inch.  And, most manufacturers suggest running
at least 25 feet of pipe before your separator, in the configuration of a
sloping trunk (away from compressor) with top taps.

Hope this helps,
Paul

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From: [email-masked] (Garrett Lambert)
Date: Tue, 01 Apr 1997 11:21:58 GMT

I didn't see the original request for info, but I want to thank you
for it. I, too, have been wondering how to size a compressor for my
shop this summer. Your approach is very practical.

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From: Robert Krecak <[email-masked]>
Date: Tue, 01 Apr 1997 23:01:59 +0000

> Which is better, the Newer Oilless type or the "OLDER" Oil in the sump
Joe,
The kind and quantity of tools you will be using will determine the size
of compressor needed. The key indicator of performance is cubic feet of
air per minute at a certain pressure. Typically compressors are rated at
90 psi and 45 psi cubic foot quantities. Your problem may be with the
range of tools that you listed in your post. A nail gun uses very little
air but an automotive disk sander can really eat up the CFM's in a
hurry. If you spray paint with a good gun a very large compressor will
be required. For carpentry and furniture building it is pretty hard to
beat the Rolaire. They are made in Wisconsin and are the choice of many
contractors here. They come in all different range of sizes but the 1.5
hp pancake model is portable while providing 4.5 CFM at 90 PSI. Very
adequate for carpentry tools. It is an oil lubricated model with a
pleated paper air filter. The oiless models are not as heavy duty and
will not stand up to daily use. I have the Rolaire and a large
stationary compressor to power my shop. I would say that a minimum of 15
CFM at 90 PSI is needed for automotive use. Any less and you will run
out of air with certain tools. I hope this helps.

Bob Krecak