Ventilation/Dust Control/Sound

antipodeansam · October 31, 2018, 9:27am

Kia Ora guys, have looked through the archives on this and have a few questions for my simple mind to try and get around, hopefully with your guys help.

Im extending my bay from 12” L x 8” W x 7” H with sloping roof to add another 7 ft in length, sadly width and height are what they are.

I can’t extend any further in any direction so the plan is to still have one working room at the back with a clean room with dust collection cabinet at the front. I have read all the articles I can find on dust collection and had some further questions. I plan to put an intake fan at one end of the bay, the consensus seems to be to place this just above board height. So questions…

How much power fanwise do I need/want to move the shaping and sanding dust towards opposite end of the bay? (The bay is surrounded by high fences so not much natural airflow) can I add a dimmer type switch to vary speed?
Is it possible to get a single phase fan that can be installed into the external wall to supply fresh air and is there an option for a shutter system so I can close this when it’s cold and I’m glassing. If so please point me in the right direction? I’m in NZ but at least if I know what to look for or have a US example I’ll know where to start. I have no idea about the world of ventilation.
I have a 650mm exhaust fan with variable speed to be placed at floor level at opposite end, what’s best way to utilise this to collect the dust in adjoining clean room? I was thinking a box around fan opening with a woodworking dust collector ducted to suck out of it via a HEPA filter. Shop vac will sit next to this set up and is connected to my planer and sander (via a cyclone in the bay) all of this sitting in a sound dampened cabinet.
finally on the sound dampening point any tips? I’m working out of a steel roofed shack with plasterboard walls directly on an aluminium exterior, concrete pad floor and no insulation, at 8ft don’t have much room to start framing up walls within walls?! So bit stuck… main noise is from planer, sander, air compressor and shop vac.

sorry lots of info, but the devil is in the detail, especially with so much info on archives…

thanks as as always in advance

Sam

lemat · November 1, 2018, 8:13am

like you i’m really concerned by dust collection (one room for all process) and noise (the room is in my garden). my roto orbital sander is connected to a shop vac that i’ll put in a sound box. for ventilation i use a centrifuge fan with a 500x500x90mm G4 filter before and baffle silencer after and before, ended with 600m3/h effective exhaust filter in charge. it’s really noiseless. i made those baffle with rockwool panels and géotextile glue over to prévent rockwool fibre to fly away. for intake air i use a furnace with an axial fan at the opposit top. i’ll do a celling air distributor so new air will come from a large surface at low speed right over i work to push particle and gaz more effectively (piston effect) to exhaust near soil. my work space is 4m length, 2m width and 2m high (16m3) i change all air off work space every 1,6 minutes. if you want to filter particle before outside exhaust (G4 filter is right for that) and use air silencers and keep flow, you need centrifuge fans because of working pressure.

antipodeansam · November 1, 2018, 9:31pm

Thanks Lemat, I’m working in much the same space so I am pretty much going to copy the above set up, I have a powerful 30 inch axial fan that has been donated to me so I may try and make that work before forking out for a centrifugal exhaust. So does the filter catch all the hadn sand/shaping dust? Is it worth having an air filtration unit to catch the tiny stuff that blows up into the bay and isnt canught by the vac and air flow, I mean like the sub 1 micron stuff?

flounder · November 2, 2018, 1:50am

Bonjour Lemat…Could you post a picture of your baffle silencer. Also, it’s always a pleasure seeing your work/boards.

lemat · November 2, 2018, 7:35am

I will take photo… G4 filter take near all “visible” particle it’s not a “fine particle filter as you can find” but it’s what is mostly use for polen filtering in ventilation units. Still “cheap”. I use a finer hepa one’s in my shopvac cost an arm !. So my G4 pli filter take more and more particle, when it’s full i clean it with shop vac. I need to work for my intake air no filter know but i will add one soon, a G4 one too. Axial fan flow decrease quickly with pressure so you need use high surface filters and let air free circulation wich is not effective for sound reduction…

lemat · November 2, 2018, 9:58am

the room, the intake furnace+axial fan, the outake closed then open, you can see flat baffle make with rockwool and polyseter veil over and pli filter, at this stage need to be vac clean.

flounder · November 3, 2018, 6:48am

Thanks…I’ve tried a configeration based on a car muffler, the idea and fabrication were brilliant (IMHO), but the sound was still a problem.

antipodeansam · November 21, 2018, 8:08am

Right guys, so I’m finalising plans for the refurbishment of the bay. I’m not very handy so hoping to tap into your wealth of knowledge and you can critique my plans. The room is 20 feet by 6.5 feet.

Ventilation

I plan to have a 12 inch axial fan blowing air in (1200 cfm) from the outside at about board height with a variable speed controller, baffle box on the outside to protect from rain and to dampen sound.

Now here is where it gets tricky, I have been donated a 24 inch single phase exhaust fan, now all the details have eroded off the plate, I have found the details for it by measuring bits of the fan and matching it to fan pictured below at the manufactures website, what I need to know is can I hook this fan up to a variable speed controller as well, it’s a beast, I wired it to a plug to test and it goes good, but will suck me against the wall unless I can slow it down! The exhaust fan will go floor level, I then have a reducer grill to 150mm diameter ducting outlet, I plan to duct to outside using 3m of acoustic ducting into a box with a trash can in and some filters to let out the expelled air, it will have to go up from floor level to about waist high box. My concerns are if the fan is too powerful will the shaping dust just fly around the box not settling in the trash can and quickly block the exit filters or blow back into the room.

I have a shop vac hooked up to my planer which I plan to place in a sound dampened cabinet with my stupidly noisey air compressor in the corner of the room, cyclone catching worst of it next to cabinet and hooked up via pvc pipes and flex hose.

Racks

one of my fellow teachers welded me up some racks, they will be screwed down into the concrete floor, there is a little sideways play where the top part of the adjustable racks move slightly in the sleeve (few mm), any ideas for securing this up without losing the ability to adjust height on the racks?

Sound dampening

I will be framing out the walls and ceiling with noiseline gib, silencer batts and a small gap to create a vacuum. The noisey vac and compressor will be in a box, somehow vented to let air flow but least amount of noise out. The fans will be speed controlled (hopefully) and the intake will be baffled. The floor will be covered in a roll of rubber I got hold of but my biggest problem is the door, how do I make a relatively sound proofed door without spending a fortune? One I currently have is a terrible stable door, good for ventilation but useless for everything else.

Glassing

I have to do this in same room, so I plan to make some pvc stands that will fit over the fixed metal bases. I will put glass rolls in a cabinet above the fan and all my pigments and epoxy in some sealed drawers in the corner.

Ok guys, tear it apart for me, Im not blessed with tradesman knowledge and I’m a relatively young shaper compared to many of the wise owls in here. So all advice will be gratefully received.

Kia Ora