Air compressor sound enclosure?

[RallyJon]

I have a cheapo Sears 25 gal upright oil-less compressor. Works OK except for continuous stuff like sanding or blasting.

The big problem is--it's unbearably loud. It's right in my workshop, so I'm working <10 feet from it most of the time. I measured 87dba at five feet away using a handheld sound meter.

So, I'm thinking of trying to build some sort of enclosure for it to cut down on the noise. After searching the web, I found one pretty decent example:

http://www.cianperez.com/Photo/Exposed/album_WoodWerx/Projects/Compressor_Enclosure/Pages/Compressor_Enclosure.htm

...but not a lot of information otherwise. Has anyone here done this? Are there better materials (other than flakeboard) that will absorb more sound? What type of airflow is needed to keep a compressor from overheating?

Thanks for any info, -Jon

[Emission]

I built one at the office I used to work at.

It was made of 1/2" pressboard, 2x4's, and lined with thick convoluted foam (sp?) - the foam that has all the little hills and valleys in it.

It muffled the noise to a dull humming - still loud, but much less obnoxious. It was worth the effort.

Compressors do get hot, so you want to make sure they are getting fresh cool air. We ducted a fan to ours.

[TerryH]

While this compressor is very quiet already, it resides outside mostly for space and convienence. Lid is open when used and doors opened when warm outside.

[VincentVega]

My neighbors would love that.

Good link Jon, I was planning on a similar setup myself. A buddy installed his vertical compressor in a closet he built in the garage, works great. My plan was to frame and drywall around the compressor and then install some sound deadening insulation on the inside.

[coloradoporsche]

We had a room in engineering school that was lined with this stuff......

http://www.foambymail.com/Pyramid.html

It was quiet in a freaky science lab kind of way... but it was a 10x10 room. Might help with the small enclosure, but not sure.

[dweymer]

Jon, I am planning on the same sort of thing when my compresser arrives. There is a product for marine use to insulate boat engine rooms for sound, it is avail through west marine I believe. Overheating the motor would be an issue without powered venting to outside.

Don

[Grady Clay]

The best and easiest solution is to get the compressor out of the house. The garden shed works great. You can have an additional storage tank in your garage rafters.

There are some winter issues by not having the compressor in a heated space. There needs to be a heater and automatic drain to prevent condensate from freezing in the tank. Some compressors have a low temperature limit without a crankcase heater. This is regular industrial stuff and is inexpensive and easy to find.

In warm weather it needs good air flow.

Best,
Grady

[RickM]

My relatively new CH compressor uses Mobil 1. Perhaps less of an issue in cold weather. The auto drain for the tank is a good suggestion. However, could the automatic valve freeze up as well?

[NoLift911]

Ear plugs. $1.99

Get a ten pack for the neighbors...

-Jeff

[RickM]

A note Widebody911/Thom...

" I have a 5hp 90g 2-stage compressor, in a little shed of it's own outside of the garage. This makes for a fairly tolerable work environment inside the garage, as most of the noise is eliminated. For warm days, I run the line coming out of the tank into a bucket of cold water to cool down the air and condense the water out of it. From there it goes into a Sharpe water trap."

I think he may have buried the line to eqaulize temps between the compressor and outlet.

[RallyJon]

Unfortunately a shed is out of the question--it has to be in the cellar/workshop.

I've read that oil compressors are quieter than oil-less. Is the difference significant?

[Jared at Pelican Parts]

there's always the old garage band solution, egg carton material and or fiberglass insulation..

I've had success using bituthene as a sound deadening material....

a friend of mine runs a recording studio, I'll ask him what they use and where you can get it....

[RickM]

Originally posted by RallyJon
Unfortunately a shed is out of the question--it has to be in the cellar/workshop.

I've read that oil compressors are quieter than oil-less. Is the difference significant?

Yes. Oil-less compressor emit a very loud BRAP noise. The oil crank type are a quieter Brup type sound. Like a lawn mower engine being cranked quickly but not starting.

[randywebb]

get the thing up off the concrete and isolated from it -- rubber pads/feet or even hang it on a rope...

then you have to address the wall transmission but w/o getting it overheated!!

see if you can figure out the frequencies that are being emitted -- that will affect the sapcing of absorbtion elements and types of materials used.

a cheap way to estimate this will be to switch your dB meter from A to C and then compare the characteristic curves to see which it matches... also just use your ears.

You might try searching OSHA's web site to see if they have any tips.

Outside will be best for you - but if I was your neighbor I'd kill you for doing that....

[randywebb]

oh yeh - get it as far away from you as possible -- is there an attic in your shop?

you could vent it out the roof for cooling and have more space for sound attentuation material + it will be farther away from you

[Paulporsche]

As randywebb says, decouple it from the floor by suspending it on cables or at least isolating it w/ rubber pads. If you are building a stud wall around it you can fill the stud cavities w/ sound attenuation batts, which are like fiberglas insulation. Using 2 layers of drywall (or even better, 2 layers on each side of the wall ) will help. Stagger and mud and tape the joints. Caulk any other joints (say between the floor and the wall) w/ acoustical caulk. If you need to have this thing be air cooled, can you open up a vent to the outside?

[RickM]

Originally posted by randywebb
oh yeh - get it as far away from you as possible -- is there an attic in your shop?

you could vent it out the roof for cooling and have more space for sound attentuation material + it will be farther away from you

I'm thinking the attic is the wrong place to have a compressor during the summer.

[masraum]

I've always wondered what lining something like that with the foam pads made for beds would do to the sound.



I think that might add an extra layer.

I know a guy with a band that lined a room in his house with the starbucks multi-cup holder. You know, the cardboard holder with a spot for 4 cups. He seemed to think they really cut down on the sound in the room.

[Emission]

Originally posted by masraum
I've always wondered what lining something like that with the foam pads made for beds would do to the sound.

That's the stuff I used. You can buy it commercially (look up FOAM in the yellow pages) in big sheets. Mine was gray/black in color and a bit thicker. It worked well.

[masraum]

Hmm, seems I missed the same thing in a couple of posts.

Must focus...