Thread: Quiet Air compressor - Chicago or Rolair?

I am not familiar with those particular models but generally speaking the belt driven compressors were a lot quieter than direct drive ones.
These later generation models might be different though.
As a variation to Bobs permanent insulated housing you could make up a portable enclosure out of a big plastic tub or plastic dog kennel and just drop it over the compressor wherever you have it.
Pit would take the edge off the noise.

Originally Posted by Beardy

These later generation models might be different though.

People also keep on saying that oil-free are noisy, but apparently things must have changed. 68-69dB isn't loud at all, and you can't publish specs like that and get away with it for very long if they are not correct.

I can't find it now, but somewhere on the Sydney Tools site some guy compare a Chicago with something else of similar capacity, and the noise levels in the recording are very significantly different. Now the sceptic in me says that they could have adjusted sound levels in post-production, but I suspect that they couldn't be bothered really. In other words, check it out in person if at all possible, or take a personal recommendation from a forum member (which I received by PM).

Originally Posted by FenceFurniture

My Taurus is rated at 115psi (but that's never been tested) and that would be the minimum that I require for general duties (I don't run tools or sprayers). I find that the 30L tank requires frequent filling with some of the jobs I do, and it is often running continuously for a 2-4 minute job. That is a function of the tank size, but could also be from something else that I don't necessarily understand.

Chicago 30L Silenced with Alum tank. $549
2 HP, 69dB, 3.8 amp, 100 psi (low) 100psi because of the Al tank. But I don't think that is low. I've never needed over 100psi. It's the air delivery volume that is more important for most jobs.
18kg (don't care) This is the main reason for the Al tank. Easy to load into and out of the back of your ute.
59x31x55 cm

Rolair JC20WH 20L $579 TWIN TANK
2 HP, 68dB, 4.6 amp, 140 psi max, rated at 90 psi/140L per minute
28kg
51x43x58 cm

Rolair JC25WH 20L $679
2 HP, 68dB, 6.5 amp, 150 psi max, rated at 90 psi/155 Lpm For all of these compressors the flow figures given are for the regulator set at the psi rating. The pressure switch will be set to the max figure (cut out) with the cut in set around 20psi lower. With the regulator set at 90 psi this one will deliver 155 lpm.
35kg
70x55x35 cm

Rolair JC30WH 30L $599
2 HP, 68 dB, 4.6 amp, 150 psi max, rated at 90 psi/140 Lpm
30kg
67x28x60 cm



They are all oil free and the Chicago has the advantage of a rust free alum tank, and all are free delivery.

A couple of things I don't understand about the Rolair range.
The twin tank 20L is $100 cheaper than the single tank 20L (which has two outlets, significantly higher amps, slightly higher air ratings). What is the advantage of two tanks, and why would the single tank be more $? Higher delivery. May have slightly larger cylinder capacity.
Presumably there is some advantage to two tanks because the 30L single tank is only $20 more.

When they say 90 psi at 140 Lpm I presume that is for continuous running, and the "max" psi rating are when the tank is full and waiting for use? Is that right? Max psi is the recommended maximum working pressure of the tank and compressor combination . The tank will be rated significantly higher.


Interested to hear any experiences with these brands (I know some have the Rolair), or suggestions of other non-dental options

A longer hose doesn't mean less pressure. With no leaks the pressure is the same in the whole system but the hose acts as additional reservoir so your cycle time will be longer. A 30m 1/2" hose is around 3 litres in volume. I'll give you a call tomorrow.
I think I have a spare water trap/regulator here somewhere.

As the owner of a rolair jc20 plus, all I can say is that it's a ripper. I replaced a Diablo 20lt twin tank direct drive(now in the shed for casting).... Noise wise, I can't comment on numbers as I don't carry a dB reader around with me, but when older model (even belt driven compressors) start up on site everybody knows about it. With the new 'quiet' compressors I could easily start it at 7am on a Sunday and not be concerned waking the neighbours

The Chicago that a fellow workmate has isn't as quiet, though is significantly quieter than conventional compressors. Standing next to them, two people can have a conversation without having to scream over the noise.

I'd recommend asking for a demo before a purchase to back up what I'm saying as I really am impressed with them. And if your spending $800 on something, then I believe that a demo shouldn't be out of the question

Mate! What an excellent thread!

Ive one of these https://www.totaltools.com.au/air-to...t-drive-fb1750 and its an absolute ripper. I pound the hell out of it on spray days (this week it has worked until it glowed red. It was a very big spray week). It keeps up 100% with me running a HVLP setup, delivering 75psi regulated to the gun with zero drop. I can run it hard with continuous spraying and it doesn't bother it. I do change the oil in it when I remember (I do spot the level every month though). Usually every 3 months. Should be more, considering, but its not a motor, just a pump.

Oil wise, no consumption and it comes out clean with no gristly-bits in it

It is a noisy bastard though. Definitely not the 7am Sunday jobbie Gabriel brags of

Intriguingly, the neighbours (all 3) have never mentioned it. I've told them, repeatedly, to tell me if Im annoying them. The blow-off at the end of a cycle is loud, plus I've often forgotten to turn it off and it fires up at 3am!!!! Ooops!

As a beastie, it is excellent.

BobL has a mighty good thread of moisture removal, well worth the read. His implementation is fantastic. For my setup I use one of these: https://www.ebay.com.au/itm/BRAND-NE...-/122271167630 it is glorious!

Though, tell you what, FenceFurniture, I saw this while looking at alternatives from your #1 post: https://www.audel.com.au/rolair-jc50...ir-compressor/

3HP, 150psi, 70dB and a FAD of 290l/min @ 90 PSI. If I were to buy another compressor, I wouldn't even hesitate to buy this!!!!! This kicks ass ! ..... if, if, if..... I very well might


edit: maybe I would hesitate. The FAD is not as the sellers claim! In this doc from the manufacturer, page 10, the FAD is below..... also to note, is that the recommended duty cycle is 50% (p7) and an auto-shutoff for cooling if it hits 70% (p11)

I'll check my current loads tomorrow. I've 3 spray jobs on, so it will be a good test. Shame I don't have a digital in-line pressure gauge to keep a constant record. Sounds like a job for BobLs ingenuity

Sydney tools demo’d a Chicago hush vs a Belt driven for me and the Chicago one was quieter.

[QUOTE=NCArcher;2129247]A longer hose doesn't mean less pressure. With no leaks the pressure is the same in the whole system.QUOTE]

It took me a while to get my head around it because that is also what I believed until I did some actual measurements. It turns out that equal pressure across the hose only applies when there is no flow - as soon the air starts to flow there friction with the walls of the hose and the pressure at the end of the hose is always less than the compressor end. To see this a pressure gauge is placed at the compressor and the other near the outlet

In theory let us look at what happens to a 30m long hose, with a starting pressure of 120 psi, delivering 5 CFM at the outlet
Everything else remaining the same;
- a 1/2"/12.5mm ID hose drops ~2 psi
- a 3/8"/9.5 mm ID , ~7 psi
- an 5/16"/7.9 mm ID ~18 psi and
- a 1/4"/6.25 mm (1/4") ~78 psi!

You can calculate these yourself using the online pressure drop calculator at Pressure Drop Online-Calculator . The actual pressure loss will depend on how straight the hose is, the size of fittings used and the coefficient of friction of the air with the specific hose material. In the online calculator model above I used the value for new plastic drawn hose, but whatever they are, it shows the dramatic effect on pressure loss when using long lengths of narrow ID hose.

This is why those coiled 1/4" plastic hoses are such poor deliverers of air flow.

With 120 psi stating pressure delivering 5 cfm, those standard 7.5m long, 1/4" ID coiled hoses from Bunnings drop ~15 psi BUT remember this is for only 5 cfm,
at 8 CFM they drop about 40 psi,
at 10 CFM they drop ~65 psi and
at 11 CFM they drop nearly all of that original 120 psi.

They are fine for things like, pumping up the wheelbarrow tyre, brad nailers, and blowing things down but not so good or hopeless at driving air tools.
If you want to maximise your flow, it also won't help if you have large ID hoses but use small air fittings.
Start by looking at your tank outlet. If that is 1/4" then you won't get much of an advantage by going beyond 3/8" on the hose or fittings.

I've just been through a complete overhaul of my reticulated compressed air system which is now some 8 years old. It uses 1/2" galv (5/8" ID) pipe and was using a mix of no name brand Nitto style fittings of various sizes (mainly 1/4 and 3/8"). I noticed problems because I tend to leave the compressor on most of the time and found it was recharging more and more often. I thought at first the pipe was leaking because it was corroded as I could see some brown water coming out of a water drain (a tap) in a low point of the pipe work inside the shed, but when I had a closer look, the internal galv coating was still fine so the brown stuff must becoming from the tank.

When I did the old "paint detergent in water onto the joints and fittings" I found all the pipe joins were fine, it was the cheap fittings that were a problem. Some of the fittings just needed to be cleaned (tiny flecks of rust had lodged on the seals) but others had corroded and needed replacing. I replaced all the damaged 1/4 and 3/8" fittings with 1/2" and 2 of my 5 (3/8") hoses were replaced with 1/2".

I also fitted a 0.1 micron filter to reduce rust flakes from getting through from the tank and a desiccant based air filter to remove more water from the air.
The air filter and desiccant fit into the same filter housing which is just a HD SS mains water filter housing, and the filter is a 0.1 micron standard mains water filter.
This filter protect the fittings from both rust and reduce the water vapour in the line.
I could go on and on about this but if anyone is interested I can direct them to the appropriate threads where this is discussed

A couple of useful things I found out during this process.
Blackwoods sell genuine Nitto fittings at very reasonable prices. They are pushing the "One touch" (can connect and disconnect with one hand) fittings that are almost as cheap as the originals.
Pipeonline (HOSE AND FITTINGS - CLEAR BRAIDED HOSE - Pipe Online - Retic Fittings , Plumbing Fittings, Reticulation Supplies supplied Australia wide) sell braided compressor hose by the meter at very competitive prices. The fact that you don't have to buy a whole coil of hose is itself a saving.

Originally Posted by woodPixel

BobL has a mighty good thread of moisture removal, well worth the read. His implementation is fantastic.

Thanks WP.

I have found the thread - I didn't start the thread but my filter experimentation and implementation starts here Compressed Air Feedline For Workshop?

Since the last post in that thread the filter setup has morphed a bit and now looks like this.
Apart from the standard SS HD mains water filter, the ancillary gear, hoses, taps, gauges and fittings are for calibration, testing and monitoring purposes and for ease of complete removal of the filter from the system via quit fit fittings. The panel meter on the LHS displays the relative and absolute humidity of the air in the compressor enclosure outside the shed, inside the shed, and inside the compressed air line. Super nerdy I know but that's just me.

final2.jpg

I've just had a chat with the chap from Audel Tools about Rolair compressors. He says that dust blowing nozzles are the biggest consumers of air and will empty the tank very quickly - and this is exactly what is happening to me with my 30L Taurus. That means on longer jobs (and I seem to have a few of them for one reason or another) the compressor ends up running continuously which is very bad for the pump. He says that it can be determined when people bring them in for warranty repair that they have been running them too hard because the pistons and rings are worn out.

For the same reason he strongly advises against using the old tank as a reserve (because as I observed yesterday, the pump will run for much longer but less often).

He says I need a bigger tank to do what I want it to, something like a 50L. That way the unit has a motor that is matched to the tank size and so will not be overworked. Everything he said made good sense, but dammit that's a lot more dosh!

Rolair 50L JC50WH $1099 plus $27 delivery
3hp, 70dB, 9 amp, 150 psi max, 90 psi @ 290Lpm
65kg (!!)
61x36x71 cm

Originally Posted by FenceFurniture

. . . . . That means on longer jobs (and I seem to have a few of them for one reason or another) the compressor ends up running continuously which is very bad for the pump. He says that it can be determined when people bring them in for warranty repair that they have been running them too hard because the pistons and rings are worn out.

For the same reason he strongly advises against using the old tank as a reserve (because as I observed yesterday, the pump will run for much longer but less often).
He says I need a bigger tank to do what I want it to, something like a 50L. That way the unit has a motor that is matched to the tank size and so will not be overworked.

Sounds kinda familiar

RE: blowing down nozzles:
It depends what you are blowing down - if it's small stuff then you could use an air gun with a smaller/finer nozzle which makes the air last a lot longer.
OTOH if there's a lot of sticky stuff to clean (like a "feelthee oilee" chainsaw mill) then trying to do that will a small air gun is going consume more air
A couple of years ago I bought a "long air blow" Teng Tools air gun. The "long blow" means they don't have a long nozzle but put out a lot of air in a narrower than usual air column/stream. They are not that expensive (~$15) and I found it so good I bought another , however they do use up a lot of air so I have a 3rd hose and a air gun with a fine nozzle air gun for small mechanical stuff like getting the swarf and lube out of thread cutting taps.

He says that it can be determined when people bring them in for warranty repair that they have been running them too hard because the pistons and rings are worn out.

Without trying to take your excellent thread of course to much Brett.
Why don’t they use better rings then in compressor pumps.
Auto engines run for hundreds of thousands of hours with piston rings exposed to a lot harsher environment.
Am I missing something $$

Cheers Matt.

NCArcher and I were just discussing this. He points out that the 30L ($600, free del) is only a little over half the cost of the 50L ($1100, $27 del) so in the unlikely event that I blew the 30L up I could by another and only be $73 behind. Problem with that Tony is there is a small flaw in the logic - I'd be repurchasing the machine that obviously wasn't big enough for my needs......however, given that I haven't blown up the Taurus 30L in 8 years I think the Rolair 30L is the way to go.

It's not like I'm doing those long blow jobs several times a day or even every day so I think the risk is worth it. I should also be able to rig up the old tank with a tap system so that on occasion I can run the two tanks and have a 30L x2 source. By switching the tap to the reserve 30L tank off I would only be running the pump for longer periods (to supply two tanks) every now and then, rather than permanently having two tanks to fill It would mean having to change the hose to another outlet, but that's no big deal for an occasional job.

Originally Posted by Simplicity

He says that it can be determined when people bring them in for warranty repair that they have been running them too hard because the pistons and rings are worn out.
Why don’t they use better rings then in compressor pumps.

Dunno Matt, but I guess it all comes back to price. Make the components just capable of doing what they are designed to do, but it seems to me that very few people, particularly DIY, go through this exhaustive research when buying a compressor, and that many of those units get run for long periods a reasonable amount of the time.

In other words they should be designed and built to handle a bit of continuous running without worrying about wearing them out in a year or so.

Then again.....he may have just wanted to up the ante to the $1100 jobbie

Originally Posted by woodPixel

Ive one of these https://www.totaltools.com.au/air-to...t-drive-fb1750 and its an absolute ripper.

+1 to this, I've got the exact same model and it is a great all rounder. It's quieter than a direct drive but noisier than the Rolairs and Chicagos.