Dust Collector Enclosure

[Scott Bernstein]

I have read through some of the previous threads on dustcollector noise control and have decided to build a closet-type enclosure for anew ClearVue CV1800 (with the 16" impeller from the CVMax). I am ina garage shop, concrete floor, with the DC in the corner. The garage is located on the lower level, unfortunately right under he bedooms. Thecloset will be small, around 3x4. My plan is to screw some pressure-treated2x4s to the concrete floor, then regular 2x4 for the studs and top plates for the two walls(the garage walls will serve as the other two sides of the closet). I’ll use some foam sill plate gasket materialto help keep it air-tight. I plan to liberally useexpanding foam and green-glue acoustical sealant to seal any other potential sourcesof air and/or sound leak. I have only2-3” of clearance between the top of the motor and the ceiling so I will usesome mass-loaded acoustic vinyl sheet material on the ceiling, so the motor canstill ventilate. The previous ower had cellulose insulation blown into all the stud bays in the garage ceiling, so at least that's something. All of the other wallswill have two layers of 2.5” mineral wool sound-absorbing insulation. I’ll probably lay down some of the vinylsheet on the floor as well...maybe reduce the sound echoing in the enclosure. For the dust collector filter exhaust, I’ll use abaffled HVAC vent of sufficient size. Lastly, foam gasket material around the door jam will help keep itairtight. I will also use expanding foam and/or mass loaded vinyl where the electrical cords come in/out and for the intake pipe (6").


Remaining questions… Should I use drywall or ¾” plywood for the two stud walls (which wouldbe more quiet)? I also thought the ¾”ply would be useful for mounting some shelves or other tool storage. Should I construct a hinged door with adjustablelatches (to keep it shut tight)? Or should I have the entire wall attach with3/8” bolts (no hinge), which would allow me to make the door super tightagainst the seals? I was thinking of usingthe door for storage of clamps, which obviously I would not do If I designed itthe entire wall to be removed to empty the bin.

Should I also wrap parts of the unit with mass loaded vinyl? Other suggestions?

Scott B

[Ira Matheny]

Forget plywood/OSB and the like. They act as a drum head and pass sound, even enhancing the sound.
Two layers of 5/8" sheet rock on EACH side of the new wall plus and additional layer to the existing wall and ceiling will drop the noise significantly better than anything else you can do. To improve the sound transmission reduction further, use staggered stud on the new walls. [use double 2x4 studs and 2x6 top and base plates, with studs on either side of the 2x6, but interior and exterior studs not connected and not touching one another.] Use furring strips between the layers of sheet rock will even help further

Place bottom plate on isolation material, to reduce sound transmission into the concrete.

Do not forget sound transmission thru the attachment of the equipment to ANY surface. Including concrete. Use sound/vibration isolation mounts. You can find them on line for moderate cost

[Lee Schierer]

It sounds like you are aiming toward an air tight closet. You don't say where the exhaust filter is going to be located. If the plan is to have the exhaust inside the closet your DC system isn't going to work well.

[John K Jordan]

Also, consider a staggered stud wall: Instead of a 2x4 plate on the concrete and and above, use 2x6. Then frame with 2x4 studs and stagger them so there is nothing to transmit the sound directly from the inside "drum" to the outside. Wind your choice of insulation between the studs. Take care at any corners to prevent direct sound transmission by contact. I found info on staggered stud walls on the internet, apparently used sometimes in recording studios. The foam panels they sometimes use might be useful too.

This shot is of my wall before insulating. I spaced the studs so the 4' panels would line up inside and out. I paneled this closet and the entire shop with 1/2" plywood. The cyclone is quiet enough to hear a whisper outside the closet when it's running.

staggered_studs_IMG_2013071.jpg

If you fasten the cyclone directly to any wall it may transmit some vibration through the wall. I mounted my CV1800 to an exterior wall. Some people build a frame to make it self-supporting but that might take more room.

I used insulated steel double doors for access but they don't insulate as well as the walls so I had them open into a back room in the shop that I don't use when running the DC. If the doors had to open into the shop I'd probably make some or add insulating panels.

Not much sound comes from the motor but a lot apparently comes from the impeller and the exhaust. Some people run a longer exhaust and insulate that well, with a muffler or just a lot of insulation. I would use as much insulation as possible below the ceiling. If the joist are not exposed now, I'd consider tearing down any covering and insulate that space as much as possible.

I had space to built a 4'x8' closet which comfortably houses both the cyclone and a 5hp air compressor. I'm so glad I did. I brought all controls for both through the wall into the main shop. My air return from the filters is a baffled plywood duct in the trusses but that might be a sound path to the room above in your case. Some people run the return in a cavity in the wall but that would prevent using insulation in that column.

Your installation sounds tight but doable, especially if you won't feel the need to collect dust and operate power tools while someone is sleeping above!

You will LOVE that cyclone. I have the 5hp CV1800 with the 15" impeller and it works better than I ever imagined. If you like to watch the dust swirl around the cone just don't do what I did and vacuum up some kitty litter I used to soak up a spill - it gently frosted the inside of the cone. But I can still see what's going on inside and it is kind of aesthetically pleasing!

JKJ

[Scott Bernstein]

Airtight is the idea... From an acoustic perspective I think I want control where the air flows so that I can control where the sounds travels. Any little air leaks here or there will degrade the sound attenuation. The filter stack will be inside the closet and I will have a baffled low-resistance path for exhaust air to travel outside the closet; I believe this will be satisfactory (if the baffled exhaust vent is of sufficient/appropriate size). The staggered studs are a great idea, and if I add a second layer of drywall I will definitely due to green glue acoustical isolation compound between the layers. If I have extra mass loaded vinyl I could apply that to the blower. The motor unit does hang from rubber isolation mounts - kinda too late to do anything more with that. I primarily work in the shop on weekend late nights,so hopefully all this will help.

The unit is assembled, and I will be turning it on the first time tonight - I think it will eat my Rigid shop vac for dinner.

Lastly, I purchased the bin level sensor with the unit - I figured that would be helpful with this thing in a closer.

SB

[Frank Pratt]

My collector room is in the basement adjacent to the shop/garage. the room is constructed:
- 5/8" drywall
- GreenGlue
- 5/8" drywall
- wall framing: 6" steel track with 2.5" steel studs so there is a 1" gap between the inside & outside studs
- 2 layers of Roxul 3" Safe-n'-Sound mineral wool.
- 5/8" drywall
- GreenGlue
- 5/8" drywall
I used 2 exterior prehung insulated steel doors back to back with a .5" gap between the jambs, sealed with closed cell foam. Each door has an additional layer of .75" MDF & GreenGlue secured to it, along with a second set of weatherstrip.

The floor is concrete & I did nothing special to isolate it, other than the rubber feet that the collector sits on, and acoustic sealant where the wall meets the floor. The ceiling is framed separately from the floor structure above. It is a room within a room.

Return air is via an 8" x 32" duct with a 90* bend and a dogleg, lined with fabric backed fiberglass duct liner.

I have a 5 HP collector. When I stand 3' from the closed door & start the blower, I cannot hear it. At All. If I have my ear about an inch from the door I can just tell it's running. In the office above, it can't be heard.

Mass loaded vinyl is effective, but a very expensive solution compared to just 5/8" fire rated drywall. Plywood or OSB will do very little to attenuate the sound. Expanding foam does very little to block sound. Just build it & seal with acoustic sealant.

You mention electrical cords running into the room. Don't do that. It is a code violation to run portable cords through a wall or ceiling. Run conduit or armored cable into the room & seal around with acoustic sealant. Forget using the mass loaded vinyl there.

GreenGlue makes an acoustic sealant that you use to seal gaps and they have a noise proofing compound that is applied between the layers of drywall. They are not interchangeable & perform different tasks. Other brands of acoustic sealant are available at home centers & are probably cheaper there, but the GreenGlue sound proofing compound is the real deal & I'm not aware of a comparable product.

A layer of vinyl on the floor isn't going to do anything for you. The return air must be lined with some kind of acoustic insulation & should have at least a 90* bend in it to effectively cut down the noise.

If the cyclone is noisy, that self adhering ice shield that roofers use works very well to dampen vibrations and is relatively cheap.

I probably went a little overboard with my room, but better too good than not good enough.

[Jim Becker]

Air return to the shop needs to be the same as or preferably a larger effective area than the outlet from the cyclone and should be an indirect path.