Quiet Air Compressor for Wide Belt Sander, How many CFM do I need?

[Alan Lightstone]

OK, my workshop construction, outside of needing more cabinets, is mostly done. Woohoo!!!! Only took a year.

I've gone to great lengths soundproofing it from the house (Double 5/8" drywall, Rockwool Mineral Wood Batt insulation, and Green Glue between layers of drywall). The elephant in the room, is the old Sears Craftsman (>30yo) air compressor that I mostly use for the Grizzly G0445 24" wide belt sander, spraying away dust, etc... I very rarely use air tools. The compressor is extremely loud. Easily loudest tool in the workshop. More than the 5HP cyclone.

The specs on the Grizzly only state the compressor has to provide 75psi. Nothing about CFM.

I know California Air Tools makes quiet compressors, but will their compressors provide enough CFM for the wide belt sander? If not, which other compressors that are relatively quiet that can meet the Wide-belt's requirements?

[jack duren]

Can you put the compressor outside?

[Alan Lightstone]

Yes, but really don't want to disturb the neighbors. I went to pretty great lengths to make my workshop which is in my home quiet to both neighbors, and SWMBO.

[Bill Dufour]

Reduce max pressure to 100 PSi. reduce motor pulley diameter by 1/4? Put a muffler on the intake. Some folks use a new motorcycle muffler. I used a old oil bath air cleaner.
Bill D

I bet a used two cylinder diesel engine, water cooled, would be the start of a quieter compressor. I understand they stop running below 400PSI or so. So a worn out one would be good enough pressure for a air pump. Of course you would have to remove the cam shaft and add valves into the head or even make a simple new head. I think the radiator and water pump do not need to be used. Yanmar is a common boat and compact tractor engine maker.

[Carl Beckett]

I have had a variety of compressors, they can have considerable differences in noise.

Stay away from some of the big box designs that have relatively high rotating speeds.

Commercial designs will have a common compressor head, then change pulleys to change speed to match to a motor size. This is what you want, but you want to run at relatively lower speeds.

I rebuilt an older compressor head (Ingersoll Rand 242) and put it on a relatively small tank (60gal) with a 5hp motor. Lots of air. The quietest I have had was something similar, but with a 3hp motor (true 3hp, 1750 compressor motor) which was the same pump head but just turned slower. The slower compressor speed meant it was quiet.

You can piece all this together off craigslist. For a widebelt I would guess you would not need more than a 3hp (a real 3 hp).

Alternatively if you dont need air for other equipment, I have a small Dewalt/emglo wheelbarrow type that runs at a lower speed and is a nice little unit. It can run on 110 (2hp) but I almost always run on 220.

My widebelt took more air than I expected, but I cannot tell you the CFM (my 3hp ran it. my 5hp runs it)

[Mike Goetzke]

Three years back I purchased a California Air Tools 100020C and couldn't be happier. 6.4 CFM @ 40 PSI and 5.3 CFM @ 90 PSI. I can run a ROS for my wood lathe with it with no issues.

[Jim Becker]

Knowing what the required CFM is is kinda critical for choosing an air source...you probably want to ask the tool manufacturer to clarify that since it seems to not be in your documentation. That's the only way you can answer the question about the specific compressor you mention and whether or not it will work for your needs. If the purpose of the air for the sander is merely for things like balancing cylinders or tensioning, it's probably not an "air user" and the key is just maintaining pressure in a closed system. My CNC has a requirement like that for the air cylinder that counterbalances the heavy spindle and reduces the load on the Z axis motor, for example. Almost "no" CFM is required for that task...I just need to maintain 45 PSI.

"Loud" support tools like compressors and dust collectors can have that sound mitigated substantially by isolation. The best solution is usually a sound-reduced enclosure...I have both of those things in a sound reduced closet and ambient noise from both doesn't interfere with normal speech or even listening to the radio in my shop.

[Pete Staehling]

What is the belt sander using the air for? At a glance it looks like just for pneumatic activation and controls. I'd guess it needs very little in the way of cfm. I assume if that were not the case they would have specified a cfm requirement.

FWIW I too and a happy California Air Tools 100020C owner. It is pretty quiet as air compressors go, not as loud as my DC or table saw, but still not really quiet though.

[David Kumm]

As others have said, look at the WB design. Pneumatic tracking needs much more cfm than electric eye tracking and pneumatic tensioning. If it turns out you need a larger compressor, look for one that runs at 600-700 rpm rather than the normal 1000+ for cheap aluminum head units. I can run my electric eye WB on a small Jun Aire dental compressor so that type of WB doesn't need much air. I've rehabbed old Quincy QR compressors and they are quiet and much better than anything new for cheap money. Dave

[Alan Lightstone]

I just got off the phone with Grizzly. They don't know the answer from the specs. They are going to contact the factory. So still in the dark. It's my impression that it doesn't use much air. It's rare that my present compressor has to recharge its tank while using it, though there is a 30 gal tank on my compressor. I don't think it's an electric eye machine.

[Robert L Stewart]

I have a 1975 Sanding Master that has air tracking. This style is like a leak in ones system. Looking forward to converting it to electric eye or better one day.

[Carl Beckett]

Mine takes more than I thought it would.

A quick google I see some posts suggesting 50 to 75psi and 7 CFM. This seems realistic from my experience. You would want to account for line losses.

[David Kumm]

5-7 cfm seems about right for pneumatic tracking. You can tell by looking in the machine or running it with the door open and the kill switch disabled. Dave

[jack duren]

I believe it's stating it needs 75psi continuous. So if your compressor can't keep up its going to cost you a lot belts.. when you start looking into quiet compressors your looking at cost.

[Bert McMahan]

I have a Kobalt Quiet Tech air compressor and it uses the same design as my California Air Tools quiet compressor (which got stolen, dangit!)

Quiet doesn't have to be expensive unless you need a whole lot of CFM.

How often does your old one turn on? And what kind of power does it draw? If it's a 220V unit that kicks on every few minutes, you're using a ton of air. If it's a 120V unit that kicks on once an hour, you're not using much air at all.

[Steven Cooper2]

Bert makes a good point. If your compressor is something like an 8 scfm machine and it is on 50% of the time, you are using about 4 scfm. If its on 10% of the time you are using .8 scfm etc...

you could run the machine for a whole time from the start of the compressor to the stop and then to start again and figure out the duty cycle.

[Ben Grefe]

So you have an oil-less air compressor. I probably had the same or a similar one. I upgraded to a slightly older oiled compressor and the sound has been cut in half if not more. There’s no comparison. I also have a California Air Tools mini-compressor for installing trim in my house and sure - it’s quiet, but it’s not needed in the shop.

Just go out and buy a used oiled compressor and you’ll forget those things make so much noise.

[Chuck Saunders]

The newer Grizzly widebelts are all electric sensor so you only need the static pressure to tension the belt. The older ones had an air sensor for tracking and used more.
Chuck

[Brian Holcombe]

I run the Maka and my vacuum press on a Jun-Air that I bought after David Kumm suggested it to me. It's fantastic, so quiet that I really don't know its running.

It replaced a craftsman that was unnecessarily loud.

[Alan Lightstone]

Grizzly called back and said 3-4 CFM. So even using David's 5-7 CFM estimate above to be conservative, it looks like almost any compressor will provide that at 75psi.

Anyone have a small compressor that's quite quiet in that range that they recommend?

Bert: It turns on rarely when being used for the wide-belt. The initial fill is very loud and long as it fills the 30gal drum.
Much more when doing other activities (the occasional air tool, filling a tire, etc...)

[Jim Becker]

Alan, that backs up my feeling that it's "static air pressure" that counts with that machine rather than it being a "consumer" of air like a nailer or other pneumatic tool. An auto drain would allow you to keep the compressor pressurized and avoid the long run to fill the tank. That's how my shop compressor is setup and I have it in a closet as previously mentioned so when it does run, it's in the background.

[Alan Lightstone]

Alan, that backs up my feeling that it's "static air pressure" that counts with that machine rather than it being a "consumer" of air like a nailer or other pneumatic tool. An auto drain would allow you to keep the compressor pressurized and avoid the long run to fill the tank. That's how my shop compressor is setup and I have it in a closet as previously mentioned so when it does run, it's in the background.

Hmmm... So you keep it pressurized all the time? Doesn't that mean that randomly at all hours it will run for short periods of time to refill the tank (mine does, as I'm sure there is always some fitting in one of the hoses that's not perfectly tight, so it's leaking a little air.) How doe's the auto drain effect that?

I thought an auto drain is just there to drain out condensation from the air being compressed so as not to corrode the tank.

[Jim Becker]

The auto-drain is absolutely to get water out of the tank, but since it lets a little air out each time, unless the system remains pressurized, it's not doing anything for you. Yes, a compressor will occasionally run if there is any leakage or use of an auto drain, but those run times are short compared to filling up from scratch. I do de-pressurize my little portable compressor that I use outside of the shop, but not the shop system, unless I'm going to be away. But then again, I'm in my shop nearly daily at this point and have a 60 gallon setup. It would get old really fast having to refill that thing every morning...

[Brian Holcombe]

Grizzly called back and said 3-4 CFM. So even using David's 5-7 CFM estimate above to be conservative, it looks like almost any compressor will provide that at 75psi.

Anyone have a small compressor that's quite quiet in that range that they recommend?

Bert: It turns on rarely when being used for the wide-belt. The initial fill is very loud and long as it fills the 30gal drum.
Much more when doing other activities (the occasional air tool, filling a tire, etc...)

Jan-Air, they have a ton of models.

The one I bought has auto-drain and desiccant for drying the air. I put a lubricator in-line where needed and a regulator at each tool.

[Carl Beckett]

Overkill, but I would look around and try to find something like this:

https://boston.craigslist.org/nwb/tls/d/groton-kellogg-american-commercial-air/7017684411.html

Once you drop to the smaller units, they seem to come up regularly on CL for short money (many people are upgrading to larger units)

[Pete Staehling]

One other thing I'll mention. Timing of when you run it is a factor for many of us in how offensive the noise is. Also there is a risk of meltdown or even a fire if a compressor has a leak and winds up running continuously.

For both those reasons I'd consider either putting the compressor on a timer, turning it off when not in the shop, or having it tied to the lighting circuit in some way. either electrically or by habit. I chose to set mine up so it runs it only runs when lights are turned on. That can be done in a number of ways. In a small enough shop with a small enough compressor the light switch might possibly directly control both lights and compressor (possibly a double pole switch?). Two switches that you habitually flip at the same time are another answer as would be using a relay.

[Darcy Warner]

My 200 gallon quincy 390 never gets turned off.

Not filling that tank and 500 feet of hard lines all the time.

Fuses in the disconnect and heaters in the starter protect the motor.

[Jim Becker]

For both those reasons I'd consider either putting the compressor on a timer, turning it off when not in the shop, or having it tied to the lighting circuit in some way. either electrically or by habit. I chose to set mine up so it runs it only runs when lights are turned on. That can be done in a number of ways. In a small enough shop with a small enough compressor the light switch might possibly directly control both lights and compressor (possibly a double pole switch?). Two switches that you habitually flip at the same time are another answer as would be using a relay.

I would use a contactor for this kind of arrangement...the draw on the "lighting" circuit would be nil and the circuit powering the compressor can be anything it needs to be. The contactor just has to be matched accordingly.

[David Kumm]

I wired a toggle switch on the coil of my contactor so I can disable the pressure switch when I don't need to run the big compressor. Dave

[Alan Lightstone]

My 200 gallon quincy 390 never gets turned off.

Not filling that tank and 500 feet of hard lines all the time.

Fuses in the disconnect and heaters in the starter protect the motor.

I can't imagine. Wow!! What do you do that needs a 200 gallon tank? I've never seen one remotely that big.

[Jim Becker]

Alan, Darcy has a VERY large shop operation...it's not a hobbyist situation.

[Darcy Warner]

I can't imagine. Wow!! What do you do that needs a 200 gallon tank? I've never seen one remotely that big.

Like Jim said, I have a big shop. I did luck out and the entire thing was hard piped for air. Main line is 2" and probably 200 feet long.

When I get everything hooked to air, I may not have enough air storage.

My compressor kicks on about 4 times a day, 45 second refill.

[Darcy Warner]

The best, small quiet compressor I ever owned is my 12 year old makita. It has been beat to death, never changed oil, great compressor.

[Alan Lightstone]

I just looked at my present Craftsman compressor, FWIW. It's rated at 6.0HP max (yeah, right :rolleyes:), 2.0 HP running (probably the real number). 33 gal tank, 8.6cfm at 40psi, 6.4cfm at 90psi. 120V, 15A, 1 PH.

Clearly that's sufficient for my wide-belt, and most other things I have used it for. It was meh the few times I used air wrenches.

I'm not sure how much I can trust the CFM ratings of compressors (maybe I can, but I'm always skeptical with tools). Do I need to get a compressor with a little overkill in CFM, or can I trust the ratings?

I was thinking of a 2HP, 110V unit.

[mreza Salav]

I have a Rolair VT25BIG which is rated at 6.5CFM at 90psi. Small and can be wheeled around. Very happy with it. It's identical to a similar Makita model.

[Derek Arita]

I'll chime in late. I recently got a Kobalt 60 gal., 3 HP, 2 stage, V twin, that's rated at 11 cfm, which is good enough for everything I do, including blasting in a cabinet. I am really pleased with how quiet it is, compared with other, smaller compressors I've owned. Also, you can't beat that price!

[Alan Lightstone]

Anyone have any experience with Eagle Silent Series Compressors?

The Eagle 2-HP, 20 gallon compressor (EA-6500) states 53dB at 25 feet, while the 2-HP, 10 gallon California Air Tools (10020CAD) states 70 dB at 20 feet, which is a significant difference.

What I like about the California Air Tools model is the already installed automatic drain valve, but the tank is only 10 gallons. But the specs on the Eagle are even quieter (if they can be believed. 53dB is amazingly quiet, especially for a compressor) The folks at Air Compressors Direct, who I asked about both of them, state that they are both very quiet.

[Bill Dufour]

I seldom use air so I have a ball valve on the output of the tank. I had to replace the check valve so it holds air for weeks at a time. It will lose pressure even with no leaks as the air cools down. But this is under a 10 PSI pressure drop. The highest output temperature I have seen was under 150 F with ambient around 85F.
Bil lD.

[Ross Manning]

If you want reasonable air volume and a quiet workshop, you need a rotary screw compressor.

Rand have some info here. Chinese versions will be cheaper.
https://www.ingersollrandproducts.com/en-ap/news/2018/eliminate-shop-noise-with-rotary-screw-compressor-solutions.html

[Alan Lightstone]

If you want reasonable air volume and a quiet workshop, you need a rotary screw compressor.

Rand have some info here. Chinese versions will be cheaper.
https://www.ingersollrandproducts.com/en-ap/news/2018/eliminate-shop-noise-with-rotary-screw-compressor-solutions.html

The rotary screw compressors look great. But are roughly 4 times the price I want to spend. Oh well.

Any info on that Eagle Silent Series? Anyone have one?

[Brian Holcombe]

This machine is nearly silent, has on-board fans and is rated for continuous duty. These are made to be used. I decided on this machine rather than the current crop of quiet compressors from the box store because of the reviews that many of them get, seemed like for every happy customer there was someone else complaining that their compressor was dead after a year.

I hunted this down on eBay for what I felt was a reasonable price, replaced a few minor parts and she purrs. Runs the Maka, runs small air tools, vacuum press, etc.

Beautifully built, well made, neatly planned interior, quality parts. My coffee machine is louder.

https://brianholcombewoodworker.com/wp-content/uploads/2019/04/img_3144.jpg

[Ross Manning]

From the specs, your Grizzly sander only uses air for tracking & tension, so air volume consumption will be minimal, and one of those Eagle compressors should easily cope. (If it has pneumatic cooling & belt cleaning you would need a large volume industrial compressor)

Here is a discussion you may be interested to read: https://www.woodworkforums.com/f155/air-compressor-wide-belt-sander-211404

I have an Australian equivalent to the Eagle EA-4000 "silent" compressor - while its significantly quieter than my old belt driven compressor, it's not silent!!

[Jim Becker]

Beautifully built, well made, neatly planned interior, quality parts. My coffee machine is louder.


And it provides a nice flat surface to put your coffee maker and steaming cup of joe while you're working. :) :D

[Alan Lightstone]

From the specs, your Grizzly sander only uses air for tracking & tension, so air volume consumption will be minimal, and one of those Eagle compressors should easily cope. (If it has pneumatic cooling & belt cleaning you would need a large volume industrial compressor)

Here is a discussion you may be interested to read: https://www.woodworkforums.com/f155/air-compressor-wide-belt-sander-211404

I have an Australian equivalent to the Eagle EA-4000 "silent" compressor - while its significantly quieter than my old belt driven compressor, it's not silent!!

Thanks for the link, Ross. And now I learned what "Bugger-all" means.

[Alan Lightstone]

And it provides a nice flat surface to put your coffee maker and steaming cup of joe while you're working. :) :D

Ooooohh!!!!! Now we're talking.

[Alan Lightstone]

So, I bit the bullet and bought the California Air Tools 10020CAD. I'm going to put an sound meter on it when I get it in place, and compare it with the old Craftsman. Should be interesting.

Hopefully its specs are real, as are the requirements of the Grizzly wide-belt sander, and it will work great.

[Tom Bender]

As Bill mentions, a tight system will hold air a long time. If you want to be sure it doesn't run at night, switch it off when you leave the shop. When you switch it back on it should not run until you use air.

[Alan Lightstone]

As Bill mentions, a tight system will hold air a long time. If you want to be sure it doesn't run at night, switch it off when you leave the shop. When you switch it back on it should not run until you use air.

My old Craftsman compressor was anything but tight. It would definitely run all night, if I didn't turn it off.