What to do with my old 97dB compressor

[Hohn]

I can't much complain about it otherwise, but my CH "ironforce" is measuring 97dB sound level standing near at about a yard away.

How loud is it? Well, it sounds exactly like this oil free Craftsman compared to this Quincy:

So it's much louder than even a traditional oil lube compressor compressor that's indirect drive.

For the most part, my compressor does all I need it to do. The flow is generally sufficient to meet my needs. But doggone it's loud. Can I upgrade fiddle with the intake and such to try and get it quieter?
Is the inlet the primary source of noise?
I suppose I could remount the motor and pump and use some rubber isolators, but most of the noise is just vibration from being unbalanced in a large single cylinder.

 

[Citation]

Is this the sort of compressor you have?

Air Compressors | Fergusonhome.com

Shop Top Brand Air Compressors on Ferguson Home

www.aircompressorsdirect.com

A better air intake can help but with that compressor you might be hearing a lot of noise from the open crank on that compressor. I have a belt drive CH based compressor and made an intake that looks like what this guy did minus the PVC parts on the end. Basically just the same air filter housing + the rubber hose. It works surprisingly well. If you can attach that type of air intake it might help in your case. If nothing else, if you can use your hands to block off the intake you will get an idea how much noise you could reduce with an intake muffler.

 

[WWheeler]

My compressor is in a small closet I built pretty much just for it in the corner that I lined the walls/door nearest it with acoustic soundproofing foam panels which greatly cut back on the noise.

 

[Hohn]

Is this the sort of compressor you have?

Air Compressors | Fergusonhome.com

Shop Top Brand Air Compressors on Ferguson Home

www.aircompressorsdirect.com

A better air intake can help but with that compressor you might be hearing a lot of noise from the open crank on that compressor. I have a belt drive CH based compressor and made an intake that looks like what this guy did minus the PVC parts on the end. Basically just the same air filter housing + the rubber hose. It works surprisingly well. If you can attach that type of air intake it might help in your case. If nothing else, if you can use your hands to block off the intake you will get an idea how much noise you could reduce with an intake muffler.

That's my compressor precisely in your link.

Noise is caused by vibration, and this thing vibrates like CRAZY. I haven't dove deep, but even just completely covering the intake does very little to reduce noise. It helps, but the main noise level is still present. The design is inherently noisy due to having such a tiny lightweight pump spinning fast to make up for displacement. Because it's so light, it moves around a lot in response to compression work. The handle vibrates so much it will make your hand numb very quickly if you grab it while the pump is running.

Heavy pumps are quieter pumps. This is the lightest pump I've ever seen on a compressor of this flow class.
Other than the noise, I have to say I've been rather surprised this thing has lasted so long. I've run it to where it was REALLY hot-- like you could feel the heat radiating off the pump and motor just standing near it. I've even thought maybe I could burn it up to justify an upgrade. That stupid thing just won't die.

The air output is sufficient for what I do as well, at least with the tank size this came with.

 

[Citation]

Hohn,
Could you separate the pump from the rest of the compressor and perhaps but the pump in a noise reducing box? You would have to add air flow for cooling etc but that might help. I'm thinking of a wooden box with foam or acoustic tile lining + a fan to provide cool air when the pump is running. Some people build boxes for the full compressor but you could pull the head off and then leave the tank in the open. The result is a smaller box to build.

Putting your pump on isolators would probably help a good bit. I have a CAT 5.5 gallon compressor and you can tell several places where they worked to reduce noise. The first is obviously the lower RPM, larger displacement pump. The air intakes are designed to reduce noise as well including that stupid looking but effective bit of "fish aquarium tube" sticking out of the air filter housing. I got my idea to try the tube on my CH when I saw the little tube on the CAT compressor really makes a difference. Anyway, they also use vibration mounts between the pump and tank and a flexible hose between the pump head and tank.

Putting rubber mounts between the pump and tank as well as using a more flexible (but high temperature rated!) line between the head and tank would probably help a good bit.

 

[Hohn]

I'm toying with how to relocate that compressor head anyway because I'd like to add an aftercooler to condense out most of the water before it hits the tank.

The easy button for remote mounting would be just cutting the welds at the tank where the upper bracket holds the whole top assembly. But that's very permanent and I think would be ill-advised. I think keeping that bracket welded to the tank is smarter, as I can use that as the base for mounting the aftercooler setup.

I think I'd be better served by making a new skid from angle to mount the motor and pump to. Then I can enclose/cool/plumb that as I saw fit. The pump outlet is just a standard inverted flare.

I might be able to kill off a lot of the vibration just by putting a beefy mount under the pump and motor. 3/8" plate ought to do nicely.

 

[tak1313]

Download a simple audio analyzer app like Audio Tool (the basic one is still free I think). Use the app to see what frequency(ies) are causing the biggest problem(s). From there, it might make it easier to determine what type of noise reduction can/should be used.

 

[MacMcMacmac]

I'm sad that this even has to be asked on GJ.......

 

[Hohn]

Download a simple audio analyzer app like Audio Tool (the basic one is still free I think). Use the app to see what frequency(ies) are causing the biggest problem(s). From there, it might make it easier to determine what type of noise reduction can/should be used.

I thought about that but it's pretty obvious that a 3400 rpm motor is going to be giving you a fundamental of 56.67hz and then you'll have harmonics multiplying off that. Kill the fundamental and all the harmonics die down with it.

I also noticed early today that the motor is already rubber mounted. So it's almost entirely the exposed pump that is making all this noise.

 

[Citation]

I'm toying with how to relocate that compressor head anyway because I'd like to add an aftercooler to condense out most of the water before it hits the tank.

The easy button for remote mounting would be just cutting the welds at the tank where the upper bracket holds the whole top assembly. But that's very permanent and I think would be ill-advised. I think keeping that bracket welded to the tank is smarter, as I can use that as the base for mounting the aftercooler setup.

I think I'd be better served by making a new skid from angle to mount the motor and pump to. Then I can enclose/cool/plumb that as I saw fit. The pump outlet is just a standard inverted flare.

I might be able to kill off a lot of the vibration just by putting a beefy mount under the pump and motor. 3/8" plate ought to do nicely.

That's an all in one pump motor. Just unbolt it from the tank and bolt it, via isolation parts, to a plywood plank. You would leave the pressure switch etc on the tank and just run longer wires from the switch to the pump head. Ideally I would put a blow off valve near the head and on the tank but that's probably being overly cautions.

 

[Hohn]

Well well, it turns out this all in one is already mounted with rubber to the tank bracket.
I like your idea about moving it to a plywood plank. This would be easy to do. I could build a small cart that would have the pump/motor and after cooler setup, then take the aftercooler outlet to the tank via soft hose. But if plywood is good here, perhaps a heavy steel base is even better. Like a 1/2" plate deck on a 2x frame...


I'm looking at compressor upgrades while staying at 120V. I'm willing to put in 240V drops since my main panel is right next to the compressor location and it would be easy to do-- I have several open spots a double pole could go. The problem is that I really don't have the budget or justification for a large, immobile compressor. We're on the threshold of empty nest, and while I'm willing to leave some compressor plumbing behind if we should want to relocate, I'm not willing to mess with a 60gal or 80gal compressor cost and inconvenience when I can truly say that this compressor has delivered enough air to do all I want to do.

I'm loathe to go any smaller in air delivery, but I can say that the 6CFM range seems sufficient for my needs.

Right now, I think my best bet is probably to buy a Rolair VT25 Big, which is ironically a relatively small compressor at only 10gallons. But it has three critical features: 1) It's 100% duty cycle rated, 2) it's oil lube and much quieter at 85db (still loud, but tolerably so and a lot better than 97dB!), and 3) the air delivery is a stout 6.5 SCFM while still only drawing 13.5amps. That last part is critical because the current 20a circuit is shared with a chest freezer and some other stuff. I can't be tripping those breakers by going up to a compressor that wants a 20a breaker to itself. And if we move, having a compressor that still works on 15a if for some reason the new place doesn't have 20a will be important.

I don't keep my air system pressurized. And while it's nice to have 30 gallons of buffer tank to work with, it means waiting too long for quick air up jobs like filling tires and such that just need 40-80-psi.

So I'm thinking a system like this:

Rolair VT25---> shop air plumbing--> Receiver tank(s) at air drops, with ball valve shutoffs to disable or enable the tank capacity. I have a little Hitachi 10gal air tank as well as I'd have the old Ironforce compressor to use as a tank.

So if I laid out my garage this way, I could have a variable/selectable air storage capacity of 10gal (plus piping) 20 gal (plus piping), 38gallon (plus piping), or 58 gallons plus piping. Granted, at 6.5 SCFM, that full 58 gallons will take awhile to fill. But in the rare event I'm doing something that needs a long period of time of air use, then that's the tradeoff. (it's rare for me and tank storage and time are cost effective bandaids vs going bigger on compressor.)

The duty cycle rating of the Rolair means it can handle this kind of use, and I can even pad things by setting the cut in slightly higher (120 or so vs the 110 I think it comes set to).

 

[slowtwitch73]

I ditched air tools long ago due to noise. Have a small compressor I plug in for tires etc once in awhile.

Electron hose all the way.... Zeus juice baby.

 

[Hohn]

I have corded, cordless and air. They each have their place.

 

[Citation]

How often do you need the 6cfm? Is it most of the time you need air or just occasionally? I picked up my 2.3 cfm 5.5gal CAT compressor when the wiring in my garage was not sufficient for my bigger belt drive compressor. So for a year or so that little compressor was all I had. It actually worked well and if I didn't already have the bigger compressor I probably would have just stick with the small one. The difference in output only matters when I use my air drill or cut off wheel. I guess it also is helpful when using the blue gun. But for airing tires, or bursts with the impact wrench the difference is minor.

So could you just get a second compressor? The quiet Goodyear at Walmart for $180 is really quite nice (and delivers on the quiet part). I picked one up for a friend. Under $200 for a quiet compressor then use the noisy one (or both tied together) when you need more air.

 

[Firebrick43]

I'm sad that this even has to be asked on GJ.......

You think the op should do metal work in flip flops and shorts like the imbeciles in the video?

 

[MacMcMacmac]

Tongue was firmly in cheek.

 

[Hohn]

How often do you need the 6cfm? Is it most of the time you need air or just occasionally? I picked up my 2.3 cfm 5.5gal CAT compressor when the wiring in my garage was not sufficient for my bigger belt drive compressor. So for a year or so that little compressor was all I had. It actually worked well and if I didn't already have the bigger compressor I probably would have just stick with the small one. The difference in output only matters when I use my air drill or cut off wheel. I guess it also is helpful when using the blue gun. But for airing tires, or bursts with the impact wrench the difference is minor.

So could you just get a second compressor? The quiet Goodyear at Walmart for $180 is really quite nice (and delivers on the quiet part). I picked one up for a friend. Under $200 for a quiet compressor then use the noisy one (or both tied together) when you need more air.

Honestly, I’m not sure what I really “need”. The portion of the time when I’m turning it on to power actual tools (vs inflation) is about 75%. And it seems lately I can’t avoid having to use my big air hammer— it’s always something that needs whacking and massive abuse. That could change, but so far, I’m pretty close to needing that 6 CFM.

You might have seen my previous digression/diatribe on air tool CFM vs compressor CFM and all that baloney. So fed up with the ratings and such, I attempted to measure and get some empirical data. Alas, the flowmeter I bought wouldn’t survive full air tool pressure, but before it blew, I got a fleeting glimpse at 8 CFM draw for my biggest air gun and 5 or so with the die grinder. I never got to measure it, but my Chief air hammer is likely the biggest spender. Though it will get out ahead of my compressor, I often need a rest as much as the compressor does on a marathon session, so there’s that.

At this point, I’m thinking a smaller tank would be a *good* thing. My loud oilless takes 7 minutes to fill 28 gallons from empty and it takes over two minutes to recover. The tank is a bit too big for this small pump. So I’m simultaneously thinking this isn’t really a 6CFM compressor (my own calculations based on time to fill would put it at more like 5.5) and yet it seems to be mostly enough.

What I’d really like is a bit more pump and a bit less tank.

Rolair has a nice 20gallon 1.5hp unit that’s rated over 7CFM. It would be perfect I think. But dang that Rolair quality is pricey.