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Looking for recommendations for "quiet" air compressors

beckerkumm

Hot Rolled
Joined
Aug 5, 2014
Location
Wisconsin Rapids WI
I totally understand.

To me this is kind of like when someone is seeking advice on a new lathe and everyone says just get an old machine for all the normal reasons. While we'd all love to have Monarchs and ATWs finding one in acceptable condition, when you need it just isn't always an option.

Programmed via Mazatrol

Fair point. To buy smart with used and save money to accumulate wealth, purchases need to be anticipated early and bought when the opportunity occurs. When you need something soon you seldom have any ability to save money. Life is full of some of both. Dave
 

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
Fair point. To buy smart with used and save money to accumulate wealth, purchases need to be anticipated early and bought when the opportunity occurs. When you need something soon you seldom have any ability to save money. Life is full of some of both. Dave

Amen to that!

Programmed via Mazatrol
 

Mike Henry

Titanium
Joined
Aug 18, 2001
Location
Batavia, IL USA
No love for California Air Tools yet? They make pretty nice small quiet compressors.

Here's a 4.0 HP 60 gallon tank, looks about the biggest they offer. It's actually two dual-piston 2HP compressors on a 60 gallon tank, spinning at a modest 1680 RPM they rate the sound at 75 dBA.

I have one of the smaller models in my basement and can hear it a floor or two away when it is running. Mine tops out at 120 psig and they are quieter at lower pressures. According to California Air they are meant for only intermittent duty. I'd have to agree, having repaired parts on two of them so far in very light use.
 

newtonsapple

Cast Iron
Joined
May 16, 2017
Let's start with the basics.

What is the min pressure is required for highest pressure application?

What is the max CFM you need to provide for longer than 5 minutes? Short duration volume demand can often be met with storage, but longer demand requires compressor output.

How steady will that demand be over the course or a day? 30 minutes then off for 2 hours or 4+ hours straight?

It seems like you are anticipating intermittent use. This generally rules out oiled screw compressors as they like to run continuously and their benefits are reduced with highly fluctuating demand.

How quite do you need want to be?

I work in medical device manufacturing where oil lubed compressors are a problem. The upside of oil free compressors is that the only lube in them is the isolated air end bearings, which are grease lubed, and are not so picky about temperature. Everything I run are scroll compressors, which also have the benefit of being super quiet.

Most of my work is with small companies and the compressor sits in a closet outside a cleanroom, right near cubical land. Being 49-55 decibels is really nice*. The 63db of the Eastwood is notably louder.

I have run Powerex enclosed and Atlas Copco SF series compressors and have been fortunate to be able buy used compressors without issue. Medical operations are fickle enough, these can show up with low hours with reasonable frequency. They are VERY expensive new https://www.compressorworld.com/oilless-scroll-air-compressors/enclosed-scroll-compressors

Run hours are important on these. The seals require rebuild at 10K hours and will self destruct if run too far. The limit is 5K hours for the high pressure (115-145 psi swing) version. They also use some magic $400 grease at 10K hours or 10 years. https://www.compressorworld.com/new-style-grease-gun-kit-gun-grease-included-ip616201aj.html

If anyone knows how to get that magic grease cheaper, the 16 year old, 2500hr scroll in my home shop would thank you.

So keep an eye out for a used oilless scroll. My average purchase price is sub $1000. I just got in this 5hp single phase high pressure model. There is some mud and scratches on the banding on the near top edge, appears it was flipped in transit. How is beyond me, but I am not longer surprised. Appears to be okay, entire motor/pump is suspended on dampers and the only obvious concern is the end of the motor shaft dented the enclosure. I'll get it wired up in the next day or two. These don't appear to use Baldor motors anymore.
IMG_0462 (1).jpg
IMG_0464.jpg

*I am not sure their sound measurements account for the distinct gurgling noise these experience upon reaching pressure. The check valve on the ones I have are installed after the aftercooler and their is no unloading valve, so the scroll actually runs in reverse to unload the modest air volume on shutoff. I relocate the check valve to the upstream side of the aftercooler. The starting load will ramp a bit quicker and the check valve sees higher temps, but it is MUCH quieter.

I also think the 13 gallon tank these come with is silly. Buying used, I abandon the tank and run directly to the dryer (heatless desiccant or refrigerated) and then to an 80 gallon tank. I have never drained a drop of water from a tank, other than the water from the original tank. First one I bought had 12 gallons of rusty water in the 13 gallon tank with 900 hrs. Prior owner also never drained a drop of water from a tank. It has 2000hrs on it now a few years later.
 

SteveM

Diamond
Joined
Sep 22, 2005
Location
Connecticut
My nephew put a large upright air compressor in a framed box with an access door on it.

Insulated it with soundproofing insulation (e.g. Roxul Safe and Sound, not R-value thermal insulation) and you can hardly hear it running.

For more sound reduction, make the top and bottom plates out of 2x6 instead of 2x4, put the interior studs lines up with the inside edge of the 2x6 and outside studs lines up with the outside edge of the 2x6 - that way the interior wall and exterior wall do not touch. A friend of mine built a recording studio like that and they can play at full tilt boogie inside and the neighbors can't hear it.

Steve
 

OTBox

Aluminum
Joined
Apr 15, 2005
Location
Pittsburgh, PA
So opinions on this topic are a bit like a rear end... we all got one.
I got really lucky and my local Quincy distributor told me where there was a QGS 7,5 rotary screw compressor that someone had taken meticulous care with maintenance (they were upgrading). I picked it up for $2500 (if I recall correctly) plus a UHaul rental! I got this in January of 2019.
I have a VF5XT and VF3 and two Flexarm tapping stations in my place. I am a custom machine builder and so work surges in my place. This thing is not anywhere near 100% duty cycle except during heavy tapping runs.
The screw compressor is about as loud as my air dryer. With no sound deadening. The autodrain is louder.
As far as noise goes, I should have purchased one of these much earlier in life. No more embarrassing compressor noise in the middle of phone calls. No more gritting my teeth as the IR T30 I have disturbs my pheng shui. And no more getting starved on air when running the flexarms.
I had an SMC air dryer already so this QGS was a perfect fit.
While making all these updates I also put in copper pipe air lines. I was able to mount and solder all the joints myself so it just cost me pipe and fittings. For my shop this worked out well. I considered the aluminum piping but one neighbor in my industrial "park" did aluminum and is now constantly fighting air leaks.
Quincy does oil/lubricant analysis which can tell you the state of a screw compressor - to a degree. They charge you for it, of course...
Working on the screw compressor isn't too bad. I replaced the two filters and replaced the oil and the hardest part was unscrewing the oil filters, but I don't normally futz with oil filters so for someone who isn't a newbie to that sort of thing it would be a piece of cake.
I admit I got lucky with this purchase but for once I made a portion of this luck!
 

chip-load

Plastic
Joined
Jul 12, 2019
Agree a screw is the ultimate. But initial cost can be a driver for many. But another, not talked about issue with a screw, is the cost of ongoing maintenance. Their "special" oil, purchased only from them if you want to keep the warranty, is ridiculously over priced and required once a year!
 

chip-load

Plastic
Joined
Jul 12, 2019
(edit . . . )So far in my search I've got a favorite top 3. I am looking in the 3-5 HP range and 60-80 gallons or so (although smaller tank would not be a bad thing)
-Eaton 80 gal 5 HP: Around $26-2700 delivered I believe

You got that right. By "Eaton" I assume you mean Polar Air. Its low RPM and you can add a silencer option!

Short story . . . I was leaving them a txt msg about 2 am my time (4 am their time) thinking I would get a call in a day or two. Within 2 minutes the owner texted me back. Can you believe that . . . I was blown out of the water!! I then called and talked at 4 am! With Polar Air you are dealing with either the owner or his sister. With Quincy you are dealing with a far removed distributor. After-sale support, oh sure!
 

52 Ford

Stainless
Joined
May 20, 2021
My nephew put a large upright air compressor in a framed box with an access door on it.

Insulated it with soundproofing insulation (e.g. Roxul Safe and Sound, not R-value thermal insulation) and you can hardly hear it running.

For more sound reduction, make the top and bottom plates out of 2x6 instead of 2x4, put the interior studs lines up with the inside edge of the 2x6 and outside studs lines up with the outside edge of the 2x6 - that way the interior wall and exterior wall do not touch. A friend of mine built a recording studio like that and they can play at full tilt boogie inside and the neighbors can't hear it.

Steve

There's a company that makes drywall hanging brackets that isolate the vibration from the framing for that exact reason.

Vibration dampening is the name of the game. I keep pancake compressors under my workbenches for little stuff (no central air right now) and found out that sitting them on fairly thick silicone pads makes a WORLD of difference in sound and vibration. Even with the compressor sitting on a wooden shelf, I can't feel any vibration in the shelf when it's running.
 

Lock

Aluminum
Joined
Oct 7, 2019
Eaton and Emax are the same and I’m pretty sure flexzilla is rebadged Eaton aswell. Had a long convo with a reputable compressor dealer last month and the topic of Eaton being imported and not made in USA like they claim came up. This alone makes them loose serious cred to me.

If I had to buy a piston and noise was a major concern Puma makes an enclosed compressor thats on casters and is quite, don’t know the model but saw them at. Shop locally and were quite impressive.

Also those Eastwood scrolls have some serious moisture buildup issues, do some serious reading before going that route… there beta testing on customers and I’m not sure if they got there poop together yet.
 

surplusjohn

Diamond
Joined
Apr 11, 2002
Location
Syracuse, NY USA
I know you said you cant put it out doors but are you sure? A long airline doesnt hurt so if you had to put the compresser in a garage or shed 100 feet away it is easy to run an underground air line. My partner owns a frame shop and has a little jun air compressor and you can hardly hear it run. Pretty small capacity but maybe you can run more than one and switch them on as needed. Just an idea.
 

teemfan93

Cast Iron
Joined
Dec 5, 2015
I figured I would provide an update as to where I landed.

After consideration between used vs. Eastwood vs. Silent Piston (Polar Air, Emax, Flexzilla) I went with the Eastwood compressor. Some of my reasoning:
-3 year warranty on the new compressor
-My shop is small and packed full (about 2 car garage size). The smaller footprint of the Eastwood was an advantage to me, and with it being more horizontal orientation it allows me to build a platform up high to mount it on
-The eastwood is quieter than all the piston ones
-Even though the CFM is slightly lower, with my CFM requirements and my supplemental dental compressor I am more than covered.

Hopefully this helps someone out in the future when they are looking for something similar. I appreciate all the discussion and recommendations
 

toolmaniac63

Plastic
Joined
Dec 12, 2008
Location
Missouri
Posting after the fact. Experience from buying a compressor when mine went down in the middle of a job I had to get out the door.

Compressor that went down was IR and did not have rebuild kit.
Make sure output of compressor is close to or more than consumption of machines on air system- pressure and flow.
Piston compressor should not cycle more than six times per hour. Not sure if this applies to pressure lube machines and doesn't apply to screw machines. Screw compressors are expensive and expensive to maintain- big advantage is no oil in condensate.
Can add additional air tank to keep compressor from cycling more than six times per hour. Faster rpm compressors are louder. Try to listen to actual compressor before buying if noise is a concern. I agree with recommendations on sound reduction but enclosed, insulated box may cause compressor to run hot. Most noise generated from air intake. If you need dry air have this built into system up front- piping to cool air with drain or aftercooler, etc. Will need method to drain water from tank- manual or automatic. If oil in condensate should dispose of properly.

Bought an American made compressor out of MI and 1st machine had pin hole leak in weld on tank. Had to return 180 miles (none in area to replace downed compressor) which was a mild hassle. Second compressor had leak in intercooler casting (just my luck). Sent me a replacement intercooler and no further problems. Customer service was great but just caused some time and mileage.

My two cents
 

rklopp

Diamond
Joined
Feb 27, 2001
Location
Redwood City, CA USA
How’s your Eastwood scroll doing? Do you run it on a 20-amp breaker? I ask because the local high school robotics shop needs a new compressor that will run on a 20-amp 240-V breaker. The existing piston unit is a cheapie 14 CFM piston unit that the circuit can’t handle reliably. It sucks when the Haas TM-1 errors out due to low air. I like the idea of a quiet scroll in the school. There is a snowball’s chance in hekk of upgrading the circuit.
 

Cole2534

Diamond
Joined
Sep 10, 2010
Location
Oklahoma City, OK
How’s your Eastwood scroll doing? Do you run it on a 20-amp breaker? I ask because the local high school robotics shop needs a new compressor that will run on a 20-amp 240-V breaker. The existing piston unit is a cheapie 14 CFM piston unit that the circuit can’t handle reliably. It sucks when the Haas TM-1 errors out due to low air. I like the idea of a quiet scroll in the school. There is a snowball’s chance in hekk of upgrading the circuit.
I still like mine. It keeps up with my Fadal 4020 with no issue and I've had no issues. I've still not changed the original oil....oops.
 








 
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