A dust collector should be one of the first major purchases for any woodworking shop. Not only do they help keep things clean and tidy, they also protect your lungs from harmful airborne dust. A dust collector is only as good as it's filter, and as filters fill up with dust it reduces airflow and efficiency. One way to reduce this is to create a chip separating baffle, which collects most of the debris in a trash can before it reaches the filter. This instructable will show how I created a chip separator for my dust collector.
Step 1: The dust collector
Being on a tight budget, I chose the 2hp model from Harbor Freight. I waited until it was on sale, and then used a 20% off coupon making the total price around $165 with tax. I think the 2hp rating is a little overly generous, but it still can't be beat for the money. The filter that comes with it only filters down to 5 microns, which means it won't collect the dust that is most harmful to your lungs. Rather than spend a bunch of money on an aftermarket filter, I decided to vent my system outside, eliminating the filter completely. I highly reccomend this approach if you're able to.
Step 2: The recepticle
Step 3: Taking apart the dust collector
When I first bought the dust collector, I assembled it in the standard configuration so that I could test it, and compare the results to my finished product. I then of course had to take it all apart. The only pieces we'll need are the motor and fan assembly, the center ring, the hose, and the fittings. You can skip this step if you're buying a new un-assembled unit. Most of the excess parts went into the scrap pile, but the casters were actually pretty nice quality, so I think they will go under a new rolling tool cart I plan to make in the near future. The center ring has 6 holes in it where the supports bolt on. I simply used the bolts to plug these holes.
Step 4: The baffle concept
His design puts the baffle under the lid, and it fits down into the recepticle. This would be a little tricky for my plastic barrel trash can, as the sides are convex. I thought that the center ring of the dust collector would make a great housing for the baffle, especially since it already has a lateral inlet. It also has a cone inside that is intended to keep chips down in the bag with the stock set-up, which should only help with keeping the cyclonic action going. The other advantage this has is that it allows me to use the full capacity of my trash barrel.
My idea was to create a disc that would fit on top of the trash barrel, and that the center ring would then fit on top of. There would be a channel cut out of the disc near the perimeter of the barrel 2/3 of the way around, emmulating the Phil Thien design. A second disc would then be fitted on top of the center ring, and the blower could then be mounted on top.
Step 5: Making the bottom disc
With the grooves cut, and everything test fit sastisfactorily, I then marked out the channel. The Thien design uses a 1 1/8" wide slot that runs 2/3 of the way around, but it is designed for use with a shop vac, and a smaller diameter trash can. I wasn't sure how the lower static lift and higher airflow of a dust collector would effect the design. I had a suspicion that mine would need to be larger, but I decided to use 1 1/8" to start with, so that I could enlarge it slightly later if I felt it needed it. I drilled 1 1/8" holes at each end of the channel, and then used a jigsaw to cut the rest out. I could have use my circle cutting jig again to make a perfect arc, but I would have had to make several passes to cut the full 1" depth, and the jigsaw just seemed quicker and easier at the time. Since I want the chips and dust to fall into the barrel, but not come back out, I used some sandpaper by hand to slightly round over the top edges of the channel.
Step 6: Making the top disc
Step 7: Creating the gaskets
Being that the barrel and center ring aren't perfectly round, and it needs to be close to an airtight seal, I wanted to form some sort of gasket where everything fit together. I decided to lay a bead of silicone caulk in each of the three grooves I had routed, and then used my finger to smooth them into a convex shape that would help contour to the mating parts. This creates a flexible and airtight seal. The silicone takes 24 hours to fully cure.
Step 8: Assembly
Then I mounted the top disc with the fan and motor assembly. I used the short length of flexible hose that came with the dust collector as a vent. I wasn't comfortable installing it permanently just yet, so I just ran the vent hose out the nearby window for now. I plan on using a dryer vent for the final permanent installation.
Step 9: Flipping the switch
Step 10: Testing it out
After a minor adjustment to the inlet alignment, and enlarging the slot to 1 1/4", I was able to improve the performance even more. During most normal operations there is so little dust being exhausted that it can't be seen with the naked eye. Sucking up a large pile of dust, or taking heavy passes with the jointer or router table will create enough fines that the exhaust is visible, but just barely. So far I've filled the barrel just over 3/4 full, and there doesn't seem to be any scrubbing or loss of airflow so far.
I currently have most of my equipment on wheels, and they are all set up at the same height in order to use the same outfeed table behind my tablesaw for everything. This makes it practical to install the dust collector near the outfeed table, and just use one 10' flex hose for everything. I may install permanent ducts sometime in the future if I ever expand my shop, but this set-up seems to work well for now. The only machine the hose doesn't reach is my bandsaw, but it doesn't create much dust, and I think the higher static lift of my shop vac works better for my bandsaws dust hood set-up.
I made a few modifications to my contractor style tablesaw in order to get more efficient dust collection with the new set-up. I used a piece of hardboard with magnets to form an enclosure for the back of the saw. I also used some magnetic sheet material (old car magnets) to reduce the gaps between the frame and the table top, as well as the slot on the front of the saw. These can all be easily moved for making bevel cuts. The last modification was to drill a hole in the ZCI just behind the blade to help reduce above the table dust. This has reduced above table dust by about half.