Window Fan (to get dust out of the shop in the first place)
Whenever I am generating a lot of dust I open a window or door on the opposite side of the shop and turn on a window fan. You can pick these up for around $5 at thrift shops. I have two, and use them in a push/pull configuration to cool the shop in the summer.
I use my compressor to blow off equipment from time to time and to blow out the filters in the dust filtration unit and shop vac. This is a cheap oil-less unit; if I had it to do over I would purchase a more expensive, but less noisy, oil lubricated unit.
Here is a tip that I discovered quite by accident. To blow out my shop vac filters, I take them outside and put them over the end of a rake with a small nail in the end to center the filter. When the compressed air hits the pleated filter it begins to spin very rapidly. The combination of centrifugal force and the compressed air cleans the filter very effectively.
Dust Collection (gets the big stuff)
The majority of dust, at least volume wise, can be removed with a dust collector. I use a Jet DC-650 which is connected to one tool at a time with friction fittings. A short piece of 4" flexible hose with a flared friction connector is attached to the dust port of each machine. The dust collector hose terminates with a tapered male connector which I made from a standard union turned down to fit the friction fittings. From its normal location in the corner of the shop, the dust collector will easily reach my table saws, radial arm saw, router tables, sanding table, and the floor sweep station where it is usually parked. A low micron rated bag is used for the top filter.
All of my tools either came with dust ports or I have installed them. The two exceptions are the lathe and drill press. I use an old shoe lace to tie the dust collector hose near the piece being sanded or in close proximity to the wood being worked.
When I use the dust collector with my jointer or thickness planer, both of which generate a lot of shavings, I move it to the front of the shop and connect it to a garbage can fitted with a cyclone lid. The shavings collect in the garbage can and are easily dumped. A bead of silicone caulk around the hose where it screws into the lid will keep it from turning and seals the connection nicely.
Some tools, such as my belt/disc sander and bandsaw, are equipped with 2 1/2" dust ports, so I use a 4" to 2 1/2" reduction fitting. If I am only going to use the tool for a short period, I usually just connect them to my shop vac. This old Craftsman uses the oversize green stripe filters and really has a lot of suction. It is, however, one of the noisiest shop vacs ever made. A used tool shop that I visit often had this used Makita industrial vacuum for sale and I bought it for general clean up chores. Although quite powerful, it is very quiet. I have a collection of hoses and adapters to connect to other tools, such as my random orbit sanders and plate jointer. Every tool manufacturer uses their own proprietary hose connections, but with some sleeves and duct tape I get by.
Dust Filtration (to remove smaller airborne particles)
You can buy commercial dust filtration units and no doubt they work very well. It is easy to build your own using a squirrel cage blower from an old furnace. You can get these from a HVAC contractor at little or no cost. Most people hang these from the ceiling, or even put them between the ceiling joists if they are open. I put mine in the base of my router table. This puts it in a good location in the shop, near the table saws, radial arm saw, and sanding station where most of the fine dust is generated. My blower has 4 speeds and all are pretty quiet so I can leave it running in the background without much annoyance.
I use three 20" by 20" filters in my unit. A cheap furnace filter in the front, backed up by a 3M Filtrete pleated filter. These are removed for cleaning or replacement by removing a cover plate on the side of the unit to expose the slots into which these filters slide. The same 3M pleated filter is also used on the exhaust side of the unit, giving me a total of 3 filters.
I get a lot of questions and requests for plans for this filtration unit. I have no plans, but here is a description of the box:
My blower is a used Lennox furnace blower. I don't know what the CFM is, but it is a good sized unit. The HVAC contractor who gave it to me said that it came out of a large ranch style home. A smaller unit would work fine. This 4-speed motor is wired to a 4 position rotary switch which I got from a Grainger industrial supply outlet. This switch routes the hot lead (black) from the supply cord to one of four colored leads on the motor. Common (white) and ground (green) are wired straight across to the motor's connections.
The blower is mounted to a vertical baffle plate made from 3/4" plywood. The blower is bolted to this plywood member with cork gasket material to cut down on sound transmission. The baffle plate is likewise mounted with rubber insulation strips on each edge to help cut down on vibration. This baffle plate has a rectangular shaped cut out to match the exhaust port of the blower. This hole consumes roughly 1/2 of the area of the baffle plate and is located on the bottom half.
The baffle plate is mounted such that there is approximately 1/3 of the internal volume of the box on the exhaust side and 2/3 of the volume on the intake side. The blower is in the intake side, and the motor which is integral to the squirrel cage blower is located such that most of the motor is inside the blower.
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