Quiet Air Compressors

[Joseph Connors]

Can anyone recommend a quiet air compressor in the 5-6 HP and 25-30 gal or more size range? Noise level is paramount. Thanks!

[JGS]

[Leon]

The quietest ones will normally be "ALL" Cast Iron and oil lubricated. When shopping take magnet with you to check the cylinder and head and if possible ask to listen to the unit running. Typically the lower rpm units will be quieter also.

[Phisherman]

No such thing. Compressors are noisy by their nature. You may want to consider running the compressor in an area where noise is not an issue and run a pipeline to where you need the air. The oiless compressors generally have more noise than the one's that have an oil reservoir.

[Bob]

That's a rather blunt assessment. There are drastic differences in noise levels between compressors. A cast iron oiled compressor might run in low to mid 80 db noise level. An oil free aluminum might run in the mid 90's. Given that every 3 db increase in sound level equals a

100% increase, that would mean that the the oil less compressor might be 16 times as loud as a cast iron. Many people would anecdotally say "its at least that much louder".

I agree that none of them would be considered quiet, but the cast irons are generally tolerable, while the oil less are intolerable.

Bob

[max]

I have a little compressor called a Jun Air. My boss gave it to me because I wanted one for my nail gun but didn't want one of those big loud things. This compressor is almost silent. It is the size of a pancake but you can hardly hear it and the output is fantastic. My boss says they cost almost $1000. The photographic and medical communities use them. max

[Mark Jerde]

Either you have an outstanding boss or photo negatives. ;-) Are they black and white or color?

-- Mark

max wrote:

[RonB]

What is your concern about noise? In that size of compressor I don't believe there are any 'quiet' ones.

If this is a neighbor concern, I doubt if it will be that big of a deal. I have a 6HP CH in my garage. When it starts while I am in the garage I am occasionally startled. Outside, with the door down, I can barely hear it. I can also hear it in the house but it is not disturbing. Beside that, unless you are spraying, running air sanders or doing other things that require constant flow, the compressor seldom runs for more than a minute or so at a time. For normal use (nailing, occasional impact wrench use, some other air tools, etc.) a larger tank will usually mean less startups.

As others say, oiled compressors are generally quieter. In addition to being noiser, the oil-less machines run at a frequency that makes my hair hurt.

[max]

I work in the photo industry repairing industrial and darkroom equipment. I get a lot of cool stuff as the industry slowly dies. I have all sorts of columns, motors, gears and other stuff that I build in to tools. Oh yeah, I have thousands and thousands of negs, B/w and color. max

[Ignoramus22980]

Search for "dental compressor". I recently bought a military surplus used $7,790 dental compressor for $400. It was very quiet indeed, and has air dryers and whatnot. I resold it for $1,250, as it was too big for me anyway. The buyer was a dentist. It required 220V to run though.

Check out "Air Techniques AirStar 50" at

i

[ted harris]

You can reduce about 75% of the noise if you take the motor and pump off the tank and mount it to another platform. Of course that would be a pump that uses oil. You will have to have someone hook up the tubing for you, unless you can fabricate it yourself.

[mac davis]

the quietest ones that I've heard about are the new generation of pancake compressors, which are usually smaller than you need..

I can't remember who had them, maybe PC, but they were oiled and low rpm for lower noise level.. about double the price of the normal ones, though..

[patrick conroy]

[ Not what you asked for - but, hey this is Usenet, where we excel at answering questions you didn't ask, but we're all damned sure that's what you meant: ]

One day to get my 2Gal oiless pancake out-of-the-way, I stuck it in the base of an all 3/4" MDF cabinet, and closed the door. Out of curiousity, I plugged it in, and was shocked by the amount of noise reduction. Actually muffled down to Small 1HP Dust Collector levels (dbs in high 70's, low

80's?),

I does get hot in there, so I don't run it long with the door closed, but it has made it a usable tool now at all hours rather than only during daylight hours.

[Larry Jaques]

On 10 Dec 2004 07:02:59 -0800, "Bob" calmly ranted:

I've found that in the better made compressors (oilers, cast iron pumps) that the main noise is the intake. Put a muffler on that and you barely notice the thing running.

============================================================== Like peace and quiet? Buy a phoneless cord. http://www/diversify.com/stees.html Hilarious T-shirts online ==============================================================

[jdownie]

This "3 dB = twice as loud" error is frequently made. Alexander Graham Bell was, among other things, an audiologist. He did empirical studies of loudness, and codified a relative loudness scale Bel(l)s. 1 Bel represents a doubling (or halving) of sound pressure level. A decibel is 1/10 of a bel, therefore 10 decibels is required for a doubling of a perceived sound pressure level (on average - these are based on empirical data). To generate a 3 dB increase in sound pressure level, on a stereo for example, requires a doubling of power. I believe it is this latter relationship that is often confused with the former.

Stepping off peeve-box....

A true 6hp compressor would draw approximately 4,500 watts, or 40 amps on a 115v circuit, so you are oviously in the realm of 220+ v units.

I would look at the Eaton compressors

for what appears to be a well-made unit.

[Joseph Connors]

Thanks everyone for the ideas. I think I am going to build an enclosure for my existing compressor (6HP 30 gal upright Sears - oilless) using plywood,

2x4's, soundboard, and insulation. Just a box with openings for access to controls and air and power (plus some ventilation as well). Thanks again!

[mac davis]

You might think of adding a cooling fan.. I'm in the planning stage for a sound enclosure for the compressor and DC and plan to incorporate (damn, I used a big word!) a small attic fan with a thermostat, venting towards the neighbor i like the least..

[Hank Gillette]

Serendipitously, I wandered onto this web site just the other night:

[Ba r r y]

Good description.

I'll add that distance can affect sound level in a huge way. Placing the irritant as far from the source of irritation as possible can also help.

Most compressors can easily be placed in a convenient spot and plumbed to the area where the air is needed. They don't need to be right next to the user, or right under the wife's TV room.

Barry

[Ba r r y]

A cooling fan could even be switched on and off with the pressure switch, so it's not running all the time.

Barry