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Dust collection system Just an outline of the shop's dust collection system, I'll be expanding and updating as time goes on NOTE: Yes, I use PVC ducts. No, I don't ground them. No, I'm not worried about a static-induced dust explosion. Here's why ... Click on any picture to see a larger version. You can then use your arrow keys to move between all the images in that group.
Bandsaw Grizzly G0441 & isolation stand The core of the system is a Grizzly G0441 3HP cyclone separator. Although it can be mounted on the wall, that would transfer all the vibration to the walls and potentially act as an amplifier. Grizzly sells a stand for the unit, but I decided to build my own isolation stand. The hardest part was lifting the assembled uppper section onto the deck.
As you can see, the stand was designed so that it could be easily lifted and moved using a pallet jack. More on that later. The stand also incorporates a pair of hinged arms that attach to the collection bin lid. This allows me to lift the lid and hook it to a bungee cord, then roll the bin out.
One other "enhancement" I've made to the collection bin is a bag retainer. It's just a plywood ring with ten wooden dowel rods to hold a liner bag. Without something to hold the bag down, the cyclone will quickly suck the bag up into the cyclone. Any sort of ring or weight at the bottom will get buried, but rods hold the bag while being very easy to slide out when I'm ready to empty the bag.
A large cyclone is not a quiet beast. To keep it livable, I decided to sacrifice a corner of the shop and build a sound deadening closet. It's made from OSB, which (because of its random internal structure) dampens rather than transfers noise. It's also lined with accoustic ceiling tiles. Note the exit duct, placing the exit at the top forces air around the motor, keeping it cool. It also bends, preventing any straight sound path from the unit to the shop space.
The front wall is easily removed. If (God forbid) something on the unit fails, I just have to remove a few screws and unhook the intake and power, then I can wheel the entire thing back out into the shop.
The closet has proven to be quite effective. I measured the sound level near the filter (the loudest point) at 87 dB @ 5 feet away. Measuring from the same distance after the closet was in place, I got a reading of only 74 dB. To put that in perspective, 74 dB is just a little louder than a typical home vacuum cleaner, while 87 dB is more than twice as loud and can cause hearing damage with prolonged exposure. My ductwork is 6" PVC sewer & drain (S&D) and 6" flex hose. One of the challenges in building a ductwork system can be interfacing the main ducts and the flex hose. I've found that the 6" hose I got from McMaster-Carr fits perfectly inside S&D fittings and bell ends, as you can see in this connection between two sections.
I recommend including these small sections throughout your duct design, it allow you a little bit of room to disassemble small segments for rearrangment, insertion of new drops, etc. If you build the duct system solid and you want to add a new wye, you might find yourself disassembling entire runs to remove one small section of duct. Another problem can be getting the flex hose to stay in when the hose is hanging from the connector, the weight will slowly pull the hose out. However, a simple HVAC duct connector can be used to make a strong connection, as you can see here on the blast gate leading to my lathe. Just put a bit of caulk on the connector and slide it up into the PVC, then run a couple short screws through both, making sure you get all the way through the metal and at least 1/8" inside. Pre-drilling helps a lot.
Coming soon: more details on my shop-made blast gates and automatic starting system
So far, the most intricate collection setup I have is on the bandsaw. The cross sectional area of a 6" duct equals two 4" ducts plus a 2", which is what I've split into. One 4" goes to the standard dust port while the other is pointed up just below the lower guides. The two inch goes to a flexible duct above the table to suck in any free-floating fines pulled around by the blade. I'm capturing (I believe) all or nearly all the fine dust that used to coat the entire area around the bandsaw. I didn't want to spend $45 on another 6x6x4 wye plus the adapters to get the 2" outlet, so I made my own 2" inlet. I drilled an appropriately sized hole into the upper duct segement and inserted some 2" PVC. I then heated the 6" duct with a small heat gun to soften it while pulling down on the 2" part. In just a few minutes, I had an angled hole. After trimming the 2" piece to a proper angle, I attached it with two small screws (one inside). The edges of the hole leak a bit and someday I'll probably put some silicone caulk on it. This setup captures almost all the dust, I get a little bit escaping onto the table but I haven't puzzled out how it's happening yet. I may convert the above-table duct to a flexible hose positioned around the upper guides, my experiments so far show that this eliminates all but the occasional stray bit being thrown clear.
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