noise control

[cwearing]

Health considerations of others in my home require attention to noise control. Any suggestions to reduce the decible level of a Husky pancake air compressor in the shop would be appreciated.


Someone suggests an oil lube compressor. How great is the risk of oil in the air stream depositing on my sanded projects (using the air to remove dust)

 

[woodwish]

Get some of the thickest foam insulation you can find, usually 2" or 3" in "blueboard" if you look around. Build a box without a bottom that tightly fits around it, glue together with "Liquid Nails" for foam insulation. Cut a small notch in the bottom for the power cord and another for air hose. Cut a hole on the top or back for air to get in, doesn' really need to be all that big. Cover the hole with some air filter material, the thicker the filter the quieter it will be. Place over the compressor and add something on top to hold the cover down tightly. It will make a tremendous difference in noise level, and cost only a few bucks plus will go together in minutes. Only nuisance is picking it up everytime you need to make and adjustment, or turn on and off.

 

[Bill Boehme]

Get some of the thickest foam insulation you can find, usually 2" or 3" in "blueboard" if you look around. Build a box without a bottom that tightly fits around it, glue together with "Liquid Nails" for foam insulation. Cut a small notch in the bottom for the power cord and another for air hose. Cut a hole on the top or back for air to get in, doesn' really need to be all that big. Cover the hole with some air filter material, the thicker the filter the quieter it will be. Place over the compressor and add something on top to hold the cover down tightly. It will make a tremendous difference in noise level, and cost only a few bucks plus will go together in minutes. Only nuisance is picking it up everytime you need to make and adjustment, or turn on and off.

If your pancake compressor does not have good soft rubber feet, then get some -- it could be transmitting the sound through the floor. Before installing the thick foam insulation, which is definitely is good, I would suggest putting Hardiboard (best) or cement board (good) on the inside of the box and then spray automobile undercoating on that (you can find it in aerosol cans at auto parts stores and at WalMart). Finally, apply the rubber onto the undercoating before it sets up -- old rubber floor mats are good for this).

I guess that you already know this -- pancake compressors are the worst for noise -- they are loud enough to wake the dead -- when it craps out, get the oil type compressor that has a belt drive and one or two cylinders in an iron block or an aluminum block with a steel sleeve.

One other small item: Check the air intake filter on the compressor -- it may have fallen out or may just be a small bit of reticulated foam -- a more substantial filter can make a world of difference in noise. I second the suggestion from woodwish to put a good filter over the air intake hole on the box. This may be getting out of hand, but if you set two or three cinder blocks on top the muffler box, it will help even more.

Bill

 

[TurningDog]

I put my compressor and DC outside my shop to my deck and built a shed around them to both give me some extra space and reduce the noise inside the shop. I also added a few 2" sheets of styrofoam insulation on the inside to act as insulation but it also does a greazt job of muffling the noise.

BTW the two compressors which I run in tandem are 21 gal HF models that have a decent enough air supply and pressure to not need running very often and are much quieter than a pancake compressor and my portable unit is the double tank model which is also much quieter than my old PC pancake unit.

 

[john lucas]

It's going to be another year or so before I can put my compressor outside so I am also thining about making an insulating box. Wouldn't it need to be cooled in some way. I'm worried about heat build up in the compressor motor. I thought I would install some sort of fan but I'm worried that will defeat much of the noise supression if I cut a hole in the box and put a fan in it.

 

[Mark Mandell]

It's going to be another year or so before I can put my compressor outside so I am also thining about making an insulating box. Wouldn't it need to be cooled in some way. I'm worried about heat build up in the compressor motor. I thought I would install some sort of fan but I'm worried that will defeat much of the noise supression if I cut a hole in the box and put a fan in it.

You are absolutely correct, John. These oil-free pancake jobs are air cooled and if enclosed without sufficient airflow to cool the compressor and motor, will burn out in rather short order. This is getting to be a project, but you can solve the problem with a $10 muffin fan from Radio Shack like those used to cool stereo cabinetes.

Make your enclosure out of Homesote. Line it with R-12 (4") fiberglass BAT insulation. Cut a hole in one end of the box and install a 6 or 8" fan backed with a screen. At the other end of the box cut a 6" hole. Both holes are in the Homesote BUT NOT IN THE INSULATION. The fan is then wired to the pressure switch on the compressor so that it runs whenever the compressor does. Even better is to wire it to a delay circuit such that it will run for several minutes after the compressor stops. The fan thus provides cooling air for the compressor.

The cheaper alternative is to put the thing outside and pipe the air into the shop with 1/2" type L copper.

M

 

[Ed Weingarden]

You can always use soft foam ear plugs.

 

[john lucas]

Or you could go all out and buy the Bose noise suppression headphones. I tried a set out in the mall this weekend. What and incredible difference it makes. Unfortunately they cost $350 but If I ever have money to blow I'm getting a set.

 

[Mr. Don]

Air Noise

NAW.... All ya gotta do is get yourself an old bicycle tire pump, stick an air gun on the end of the hose, and give that smart-*** little kid down at the end of the block a buck an hour to pump REALLY fast!!!! (thanks 4 the edit, Moderator....got carried away with the spirit of the moment)

 

[MichaelMouse]

I'm not so sure I'd put something that sucks air and relies on a close piston or diaphragm fit into a box lined with fiberglass. Sounds more like fine "friable" abrasive than insulation. I'd stick with isolation methods like shock mounts, and box-in-a-box enclosures with intakes vaned away from the need for silence to make sure the sound has to double back on itself a little before coming out.

Open-cell foam is pretty good at insulation and absorption if you need it. Can also be part of your isolation between boxes.

 

[pyrocasto]

For foam why not use the matress eggfoam material? The only soundproof room I've been in was lined with the stuff.

 

[john lucas]

Our soundproof room has a special cone shaped foam that is really expensive. It's really erie being in that room there aren't any echos at all.
I would think that eggshell foam and that sort of foam would be bad for this sort of thing. The stuff gets old fast and starts to rot. It also doesn't stand up well to heat.
The main thing with this insulation procedure would be to isolate the motor vibration and noise from whatever you put around it. This might mean setting the tank on rubber pads and then using some form of insulation between the tank and walls of the box. I would probably use the blue foam just to keep the size down.

 

[woodwish]

I think we need to go back and look at the objective here, how to take an inexpensive compressor quiet without spending a lot of $$$$. The easiest way to make this quieter would be to jack it up and put a quiet design old fashioned oiled compressor, but far from the cheap way to do it. I'd still make the box out of blueboard foam or that cheaper (but not as strong) white styrofoam. It would help to line it with something to absorb sound but I sure would avoid fiberglass. Cheap foam designed as a mattres cover would be easy to use but also requires the box to be bigger, kind of a trade off here. Yeah, it'll break down in a few years but I had a feeling this was not a permanant solution. Heat from limited use is not that big of a deal but continued use would decrease the life of the compressor, I would think about one of those cheap pancake fans that someone else suggested. I would also rather use some sort of baffle design in the box to hold down the noise leaking out, but again it increases the size of the enclosure.

Probably a good DIY article for a magazine in here somewhere, make some different designs getting bigger and/or most costly materials comparing the actual sound level.

 

[pencheff]

Our soundproof room has a special cone shaped foam that is really expensive. It's really erie being in that room there aren't any echos at all.

Not trying to split hairs here but the special cone shaped foam makes the room anechoic, not sound proofed. The odd shaped foam on the walls merely removes any reverberance from the room. Foam does very little to block sound transmission. Real soundproofing material is dense, not porous.

http://www.uhfmag.com/Issue63/soundproofing.html

Just my $0.00002 worth (in 1972 dollars)

 

[woodsmanplus]

For what it is worth,Get rid of the pancake as you will never really quite them down.I have two sears 4hp and they are old,but you can barely here them from the basement.

 

[eaton9999]

It's difficult to deal with the noise. Abating it obviously is best but for an alternate I have Radio Headphones that lets me listen to FM Radio while blocking 22dB of noise. Not great but works OK. Better yet, because commercials are not what I like to listen to, nor gabby DJ's, I have an MP3 player hooked up to a RF transmitter which sends my own music to a set of wireless headphones.