Adding a Dust Collection System

After cleaning up my shop (and a lot of dust), I decided to add dust collection. A dust collection system is composed of a motor and impeller that sucks sawdust into a collection bag. Each sawdust producing piece of equipment is connected to the impeller through pipes.

One of the big things I learned midway in this project is that if you're adding dust collection, chances are you will need to put it on a separate breaker. Since I was doing electrical work in the shop at that point anyway, it wasn't a major issue. The dust collector is on its own 20 amp breaker. Make sure the receptacle is rated at 20 amps as well. To determine if you have a 20 amp receptacle, they have a horizontal slot branching off one of the vertical slots. While my breaker box is labeled, I also wrote the circuit on the actual duplex receptacle box as well.

If you don't have any big pieces of equipment like a table saw you may not need a separate circuit, but if you are using handheld equipment it's unlikely you would be installing dust collection anyway.

I started with the 2 HP Harbor Freight dust collector. Many people upgrade to a Rikon 60-200 impeller, but I didn't want to spend the $110 for it. A mandatory upgrade is the filter.

General Requirements:
Harbor Freight 2 HP Dust Collector
Piping & connectors
Blast Gates
Thien Baffle
Galvanized Trash Can
Wynn Filter Upgrade
Cost $450

Piping List (Specific to My Set up/Equipment):
(3) sections of 10'-0" 4" PVC pipe
(10) 4" PVC wye
(2) 4" PVC end cap
(4) 45* PVC elbow
(11) blast gates - DIY
(10) pipe clamps - DIY
Cost $125

Materials for Blast Gates (x11):
4" PVC pipe cut to 2.5" sections (or a coupler depending on your setup)
1/2" MDF for the Gate Body and handles
1/4" MDF for the blades and spacers
1/2" wood screws
Cost- roughly $40 depending on how much scrap you have

Materials for Thien Baffle:
Plywood top and bottom (roughly 18"x18")
Plywood Pipe Port
PVC pipe
PVC Hub Coupling
(4) 6" lengths of 5/16" threaded rod
(16) 5/16" fender washers
(16) 5/16" nuts
6"x38" LVT plank
Caulk to seal joints, gaps, etc.
Cost - $20-50 depending on how much scrap you have

Materials for Equipment Hookups:
(2) 4"x10' Flex Pipe
(3) 4" Whyes
(5) 4" PVC Flanges
Styrene to box out table saw, band saw, router
(3) 2.25" to 4" reducer
(1) 2.5" flex pipe
(13) 4" Worm Gear clamps
Cost: $60

Total Cost: $600 range depending on various factors

Tool List:
table saw with crosscut sled
jig saw/band saw
router
drill
router circle cutting jig
round file
1" forstner bit
1/8" bit/drill
5/16" drill bit
1/4" router cutting bit
1/8" router cutting bit

I bought a Wynn filter for two hundred dollars. The out of the box HF filter woefully under performs. The Wynn filter drastically increases filter surface area and will stop much finer particles.

The pleated design increases surface area which increases flow. The Wynn filter is designed to retrofit to various dust collectors. I cut out a plywood flange as the dust collector body slopes. I caulked the flange in place. The filter has worm gear straps that attach from the dust collector body to the filter. It's a neat design. You drill a hole for a screw and the bracket. The worm gear has hooks that attach to the bracket and to the metal guard on the filter.

To reduce the amount of dust that reaches the filter and to reduce any wood chips that could hit the impeller, you need a chip separator.

I built a Thien baffle. It separates chips and dust before they reach the impeller and filter. A clean filter maximizes air flow. The baffle is placed inline before the impeller, with the baffle mounted to a trash can to collect chips/dust.

My 4" PVC pipe runs right into the Thien baffle, no turns. I wanted to maintain airflow. I remounted the HF impeller directly on top of the baffle in a top hat configuration. I used the supplied HF pipe to connect the impeller to the collector bag in a straight run that is ~4" long, avoiding the longer curve of the out of the box setup. The trash can is mounted on blocks to get it to the right height that matches my pipe which had to clear my nearby counter.

To make the baffle, I built a circle cutting jig out of scrap. The trash can has a 17" diameter. The baffle is roughly the same. With a 1.5" interior slot. The inside clear height is 4.75".

I considered a Thien baffle and a cyclone. Based on space and anecdotal evidence I went with the Thien.

Cut List:
(2) 18"x19" blanks for the top and bottom
(1) 4.75"x2"
(1) 4.75"x5.75"
(1) 4.75"x9.25"
(1) 37" long x 6" hardboard panel for the sides

I started with a galvanized trash can, this dictates the size of the baffle. This trash can has a 17" inner clear diameter. I chose this trash can as I'm putting my dust collection in a corner, and I have to maintain a certain width.

While you can buy trash can tops that mimic the design and some designs have the baffle completely inside the trash can, I wanted the PVC pipe to run straight into the baffle with no 90* turns. The baffle will sit on top of the trash can with a plywood lip to ensure good fitment.

I rough cut 18"x19" blanks for the top and bottom of the baffle. Both have a 2"x5.75"x10" extension for the pipe inlet. I made the rough cuts a bit wider than necessary to leave room for the router to trim.

The top has a 5" hole for the dust collector motor. The motor outlet will feed directly to the filter bag.

The interior bottom of the baffle has a 240* 1.5" wide slot. Both top and bottom have a 1/8" wide x 1/4" channel for the vinyl sides. That channel runs right into the bottom slot.

The circle cutting jig made cutting the curves very easy while ensuring the top and bottom were exactly the same size. I cut each slot with two passes as trying to cut through .75" in one pass was too much strain on the router. The jig ensures each pass is aligned.

A 4.25" diameter hole was cut out of the 4.75"x5.75" cut. This is for the inlet.

While I used (4) threaded rods to space the top and bottom, doing this again I might have just used wood posts around the perimeter. I was reusing rods, so I had to re-thread them to clean them. The top and bottom are sandwiched with washers and nuts.

I sketched up a few iterations and while the first few didn't have space around the perimeter, the final version did as I needed a ledge for the baffle to sit on a trash can. The LVT floor plank sides are 6" deep along the slot, but 5.25" everywhere else. A quarter of an inch is inside the channel on the top and bottom plate. I didn't want to create any kind of ledge to catch dust so the sides extend the depth of the slot. Originally I was going to use hardboard, but it just doesn't flex enough to fit the diameter. It snapped trying to fit it to a 17" diameter.

A ring with a 17" outer diameter was glued to the bottom. It's 1" wide and the face is flush with the slot. This ring helps mount the baffle to the trash can.

I glued the inlet together and to the bottom first. I glued it to the top at the same time I caulked the channels for the side and tightened the nuts down for a tight fit.

I measured the nut/washer height to exactly 4.75". I tightened the bottom nuts down and then prepped to caulk the sidewall in place on the top and bottom. I wanted to be sure it was air tight. With the sides being in a channel, caulk fills any potential air gaps.

I added weather stripping to the trash can. I want a air tight fit between the baffle and can. I added a tab on one of the back corners to prevent the baffle from wanting to turn. The bottom plate needed to be about an inch wider to sit on the trash can properly.

I considered attaching springs to hold the baffle to the trash can, hooking to the can's handles and drilling a hole into the bottom plate. With the motor mounted to the wall and the way my trash can is mounted, I didn't need the springs. The trash can sits on a plywood sheet bolted to a scissor jack. The scissor jack lifts the trash can tight against the baffle which is hung from the motor. The motor is mounted to the wall. Lowering the scissor jack lowers the trash can and allows for removal.

I did a lot of research in how to set up the piping. You want to maximize air flow which means as many straight runs and as few curves as possible. Any branches need to be wyes, not tees. I have a straight run of pipe running down the wall with a branch that goes up the wall and across the ceiling. At any 90* turns you want to use two 45s and a straight run of pipe instead of a 90* elbow. You want to minimize the use of flex pipe and use tapered reducers to equipment ports if possible. My pipe height was dictated by counters. It's roughly at 42" above the floor.

The inlet of the HF collector is 5", so there is no reason to exceed that size pipe. There is debate as to whether the HF collector can provide sufficient air flow for 5". I selected 4" PVC pipe due to cost and availability. Use PVC sewer and drain pipe instead of the heavier, more expensive schedule 40 PVC. You want to maintain the 4" up to and including the machines if possible, though many machines simply can't fit a 4" line. Enlarge the ports of machines when possible. When you have to install a reducer, a tapered reducer is preferred to help airflow.

At a few machines, band saw, router, table saw, I wanted two pickups. You want to use as little flex pipe as possible, but at the machine it's unavoidable. You need enough flex pipe to move the machine as well.

At each branch/Wye, you need a blast gate to close loops and maximize air flow suction. I made my own gates. They are better as there is no track for dust to fill up and are much cheaper.

I also made my own pipe wall brackets out of 2x4s. It's recommended to fasten joints with screws rather than glue so you can open the system easily to dislodge jams. With my pipe brackets, everything stays in place. The only thing I might do is to caulk a joint if it appears to not be sealed well.

The brackets are made from 2x4s with a bracket roughly every 48". I sketched a shape across (2) 2x4s and then cut them out on a band saw. I then sanded them to smooth out the cuts and smoothed them with spackle. I drilled a hole dead center to mount to the wall and two more to attach the clamp to the base. Then I painted them. Make sure that if you use masonry anchors, the screws are long enough to fully engage the anchor. That either requires longer screws or the screw to be recessed in the bracket.

I had a few restrictions. I wanted the collector in a corner that was only 18" wide and had a garage door swing arm in the space. This meant the filter/bag could not fit in the corner. To make this work I needed the trash can to fit in the corner. I opted for a galvanized trash can with concerns a plastic one could collapse under pressure.

My pipe ran attached to the wall, which meant the Thien baffle inlet had to be against the wall. The pipe had to be higher than 36" to clear my counter, which meant the Thien baffle had to be above 36". That dictated the trash can height which would needed a 10.5" riser. The motor mounted to the top of the baffle dictated a riser for the bag/filter body so that the impeller housing outlet lined up with the bag/filter inlet. I used masonry anchors to attached 3/4" plywood to the wall to mount the motor. I bought longer screws as the ones that came with the anchors weren't long enough to go through the plywood and fully engage the anchor.

The Thien baffle hangs from the motor, I used scrap metal channel and threaded rod to create a clamp.

I had to raise the filter/bag bracket to make all this work. I added 2x6 blocks with a 1" deck board topper between the stock base and casters. I did have to drill out for bolts and bracing on the existing platform.

To dump the trash can, I bolted 3/4" plywood to the smallest scissor jack I had on hand. Lowering the jack lowers the trash can from the Thien baffle, allowing me to dump it. The plywood is cut round with a 1/4" channel for the trash can bottom edge to sit into for stability.

I put the trash can and impeller in place, a mock up to start cutting pipe. I went one piece at a time, figuring out the best place for the wye. The process went quickly. I did not caulk any joints yet, I want to make sure everything is in the right spot. That will be the last step, if necessary.

You can get cheap blast gates, but they're not great. Nicer ones are more expensive, but you can build your own that work well and don't break the bank. While I could get rather simple ones for a few bucks, I don't want a gate with a track that will eventually fill with sawdust and impede operation. The nicer gates are $12 each so I'm going to make my own.

Blast gates restrict air flow to one tool, otherwise you wouldn't get enough suction. Gates are made from 1/2" MDF for the body and 1/4" MDF for the blade as it's cheap and smooth. I need 11 for my set up.

I've got a blast gate at each piece of equipment and where my piping branches from wall up to the ceiling. I located blast gates as close to the main run as possible. My goal is always to reduce line length or effective line length when possible.

Once the gates are in place, caulk all the joints. You want to stop any air leakage to maximize efficiency. I have a ~2.5" piece of 4" PVC on each side of the gate. At a few gates I have a 4" to 2.25" adapter caulked into the gate. You want to caulk last in case you need to move/change/undo the layout. You could get away without caulking the joints unless you notice suction.

Cut List (each):
(2) 6.75"x6" 1/2" MDF Gate Body - 4 3/16" hole for the pvc pipe or 4.5" hole for coupler
(2) 6"x0.5" 1/4" MDF spacers/sides
(2) 4" PVC pipe cut to 2.5" or coupler cut in half
(1) 5.75"x11.75" 1/4" MDF blade
(2) 5.75"x1" 1/2" MDF for blade handle on each end

Initially I planned to cut couplers in half for each side of the gate, but that would just add an extra joint between the wye and the gate since I will install the gate right off the wye. Using 4" PVC removes the coupler joint. also, the other side of the gate will connect to the 4" flex hose or a 4" to 2.25" adapter. The 4" flex hose will not fit over 4" PVC pipe. I added an adapter which was 4" PVC with 5/8" cut out of it. This allows the flex pipe to fit over it and it fits inside the 4" PVC out on the blast gate. I added duct tape where the tension fit was loose.

The blade has a hole cut into it, which does make it longer, but it removes a track that could fill with sawdust. It's frequently called a self-cleaning gate. With a track, it will eventually fill with sawdust and won't completely shut, reducing air flow. My gates don't have a track, but I do need space on each side of the gate for open and closed orientation.

I created a circle cutting jig for the holes.Half of my gates had too much resistance to slide smoothly after glue up of the body. I sanded them lightly with a sander until the fit was better. It won't take much sanding, only a couple of passes.

The body of the gate is 1/2" MDF with (2) 1/4" MDF spacers on two sides. The blades are 1/4" with 1/2" MDF handle glued on one side and 1/2" MDF handle screwed on the other side.I screwed it on one side in case I ever need to remove the gate or if the fit becomes an issue and I need to sand it down, I have that option.

I used a round file to smooth out any rough cuts from the circle jig. I oriented the gate in the closed position before gluing the handle, and I did the same when screwing the other handle in. This ensures full close or full open when the handle is flush with the body.

I cut a half circle out of the handles with a forstner bit to make pulling the blade easier. I painted just the body of the gates and the handles. I was concerned that painting the blades could cause them to swell slightly and I didn't want to have to re-sand them. I also like the contrast between the white body and brown gate.

I cut 2.5" long PVC pipe to caulk into each side of the gate. I caulked the opening before inserting the PVC and the joint after the PVC pipe was in place. Have the gate closed while doing this so you don't encroach upon the blade path. After inserting the PVC pipe, ensure the blade operates and wipe away any excess caulk.

Each piece of equipment has a different size port, or none at all. I boxed in the table saw with plastic and added a PVC floor flange to one side.

I also boxed in my router table and added a PVC flange. I was going to split the pipe to collect from the base and top of the router table, but didn't have the space. I also created a port on the band saw. I didn't box out the band saw as the pipe runs almost all the way to the blade. I boxed out the other equipment to increase suction at the blade.

I measured how much 4" flex pipe I needed. After coming up short, it seems a 1.5 or even 2x multiplier for how much you need is a good rule. Since the flex pipe is exactly 4" it won't fit over the 4" PVC. I cut 4" lengths of PVC and split them along the length removing 5/8". This proved an effective adapter. I used duct tape to increase the tension fit as needed. I used a hobby knife to cut through the vinyl of the flex pipe, make sure my start and end of the cut ended on the same wire support. I then used a wire cutter to cut through the wire.

I ended up using 4" to 2.25" reducers from harbor freight. They don't taper which is preferred, but the price is right. I had considered making homemade PVC tapers, but didn't.

I got 2.5" flex pipe, not realizing the mismatch in size. I used EVA foam to fill the gaps from the 2.25" reducer to the 2.5" flex pipe and from the flex pipe to equipment. I used contact cement to glue the ends of EVA foam together. The EVA tension fits inside the pipe.

While I want my flex pipe runs as short as possible, I need some slack to disconnect equipment. Duct tape at one end of the flex pipe to compress the pipe is the solution to reduce slack.

At the belt sander I used a 45* elbow that directs right at the top. An adapter didn't seem necessary.

I also have an open flex pipe to the work bench with a PVC flange at the end. The flange provides an object to clamp. I did a few tests to see how much splitting the pick up at the table saw and band saw would affect suction. Suction is better with only one pickup, but ultimately I decided to employ two pickups. Even with a split, suction from both pipes wasn't cut in half. Also two pickups is the best way to reduce sawdust.

The following is based on my research. I haven't installed any grounding yet. Whether I do depends on whether/how much I get shocked. I'm not worried about a fire with my setup. A static ground for non-conductive duct work can prevent static-charge buildup. At a home shop it's more for comfort and to avoid small shocks. It's unlikely static build up will start a fire. To install one, simply run a wire along or around the pipe. Insulated or un-insulated 18- or 20-gauge copper wire, either solid or stranded, works fine. At pipe joints, leave slack in the wire or install bayonet connectors to facilitate opening the system in case of a clog.

Run a ground wire along each branch, and splice each into the main wire. Connect the ground wire's conductor to the dust collector's metal frame or housing. The other end should extend to the outlet port on the tool, but it doesn't need to connect to anything, except to keep it in place. The wire acts as an antenna rather than a conductor in a circuit.

If you use coarse screws for PVC connections, this also allows for tying in grounding.

The system provides great suction. The first piece of equipment I connected was the belt sander. I sanded foam as a test and it got everything.The next tool was a scroll saw. I wasn't able to box out the scroll saw well, but suction was still impressive, eliminating some of the sawdust covering the top. If I could box it out it would perform even better.

I had planned for double pickups at a few tools. I was unable to do this at the router due to space, but I don't think just one pick up will suffice since it's difficult to get a port right at the sawdust producing portion of tools.

The dust collector is loud, though I already wear ear protection when using any tools with a motor. It's also one extra step before I cut anything. I have to switch it on and make sure the correct gates are open.