I need help quieting vacuum motors.

[knight_toolworks]

After talking apart my melted fein to see how they reduce the noise it is pretty amazing to knock down a 100db motor to about 65db's with just a little foam and a plastic shell.
so the foam they use is a open cell foam a little stiffer then standard foam is. I can knock down about 6dbs by putting regular foam into the air inlet. another db wrapping the fein foam around the motor like it is done on the fein.
so any idea what foam to use? I have to order it so I need an idea what to buy.

[rcboats1]

Go to Home Depot and get the pink or blue insulation foam board. That is what I used for a generator box I made and it worked real good.

[knight_toolworks]

here are some pics. the fans are the cooling fans that lets these run in vac mode like they do. but most of the noise is from them. Just setting a piece of the foam that comes with the fein over them drops the noise from 100db to about 93db. or setting the top over them. another db or to if I cover the air inlet with foam. I tested normal foam and it did nto do anything. I can try a box of pink foam with the air intake covered and see.

[ken_rychlik]

Build a box and put a set of mufflers from central vac on the outlets. Major noise reduction.

[knight_toolworks]

Build a box and put a set of mufflers from central vac on the outlets. Major noise reduction.

that would be easy to do. even one would be enough as they don't suck a huge amount of air.

[gerryv]

Kenneth's idea has a lot of merit. A central vac muffler is claimed to knock sound levels down by up to 50% and you can get them for about 10 bucks. A couple of them with the right foam in the enclosure sounds like something that could nicely for our cyclone dust extractor as well. Thanks guys.

[knight_toolworks]

I will give it a try but it may not work. these are more to muffle the noise from airflow. the noise in my case is from that fan. just like a router. Of course that foam that fein uses may be engineered just for that use.

[bob_s]

Try putting a layer of Quiet Brace from Home Depot on the inside of the box - it is like homasote coated with tar, but only $8 per 4x8 1/2 inch thick and absorbs a lot of sound. I put it under my sheathing on the new shop and the sound level outside those walls is very different than the one wall that was standard construction.
I'm planning on using this for noise reduction on the two 220V vac motors I have, but they really scream making them awfully hard to use!
I am planning to make a muffler for my cyclone with denim cotton insulation from http://www.bondedlogic.com/ it is supposed to absorb a amazing amount of sound in the 3 1/2 inch thickness. I have the Cyclone mounted in a corner and the sound coming off the walls is terrible.

the muffler shown here http://billpentz.com/woodworking/cyclone/muffler.cfm is what I am planning on using, although some have written that an 8 foot piece of insulated HVAC duct works very well and is a lot easier.

I'll post some info as I do mine, but I'm still moving equipment into the shop so it may be a couple of weeks.

[knight_toolworks]

I tried foam rubber on the inside of the box and over the air output it did not knock the noise down by even 1db. I put soem of the foam from the fein around the motors like they are in the fein that knocked it down 1db or so. but most of the noise is from those fans in the top. I was thinking like a baffle maze to make the sound have to bounce around for awhile before it can get to the opening.
these 120 fein motors are 100dbs where the 220's I have are about 96db's

[gundog]

I had a small office in the corner of my shop that I never used so I moved both vac motors the air compressor & dust collector in that room I had to install a couple vents to return some air but it has made a huge difference in noise reduction. I bet if I put some of that egg carton foam on the walls it would cut it some more. I would worry about not keeping the motors cool so covering with foam may make your motors not last long.

This is my manifold for the Vac motors I have it ducted with ABS pipe back to the room with the Shopbot. This is so much better than when I had the motors at the table.

Mike