My Thien Dust Collector

I wanted to upgrade my dust collection system.  I have a Jet DC-650 dust collector that I bought in 2003, with a good pleated filter on top, and a plastic bag on the bottom.  The filter is stock, and according to the particle counter I borrowed, it does a very good job of catching all the finest sub-micron dust.  However, I really hate emptying the bag, because it attaches with this sleek-looking but fiddly internal spring ring.  It takes a lot of bandsaw or table saw use to fill it up, but the planer especially will generate large amounts of big shavings.  I'd also like to have something between the blower and the intake because what happens if I accidentally suck up a larger chunk of wood or a nail?  Whang!  Into the impeller, and then it gets flung into the bag where it pokes a hole.

There are trash can lid separators, but they don't work well.  I made one of my own several years ago and ditched it pretty quick.  A cyclone separator would be good, but they're expensive and take up a lot of room.  Fortunately, a guy named J. Phil Thien came up with a pretty slick and simple dust separator that combines the functionality of a cyclone with the compact form of a trash can lid separator, and he put the idea up on the web for people to build for themselves.  What a guy!  I printed out a couple of pages from his website, and they've been sitting in my pile of shop papers for a few years.  Last week, I finally got around to building one.  I made it in a "top hat" style so that the separation happens in a separate unit above the trash can, and all of the volume in the can is available for debris.

I bought a quality 10 gallon metal trash can first, about 18" tall x 14" diameter at the top.  I had a couple of 16" x 15" pieces of 3/4" melamine particleboard left over from a shelving project, so those became the top and bottom plates, and I got a piece of 1/16" clear polycarbonate 8" x 48" custom cut from TAP plastics for $10.  Polycarbonate is flexible, and will stand up to impact a lot better than acrylic, so I chose it for the walls of the separator.  It's also nice to be able to watch the thing in action.  You could also use sheet metal, which would definitely be more abrasion resistant, but I don't think it will be a problem.  The inlet is a 4" plastic dust collection elbow, and the outlet is a 4" angled coupler.

I used a circle jig and router to do almost all of the shaping.  First I used a 1/2" bit to cut a dado in the bottom plate the same 14" diameter as the trash can, about 3/8" deep.  This fits over the rim of the can and holds the separator in place.  Then I used a 1/4" bit to cut slightly smaller diameter dadoes in both the top and bottom plates, about 1/4" deep.  This will hold the polycarbonate sheet I used for the sides.  Then I used the same 1/4" bit to plunge all the way through and cut the drop slot.  This slot is 1-1/4" wide, and goes 2/3 of the way around the circle of the lid.  I set the circumference so that the outer edge of the slot is about 1/16" inside the 1/4" groove for the sides so that the inside of the walls is flush with the outer edge of the slot.  I hope all that makes sense because I didn't stop to take photos.

Here is the groove to fit the trash can rim.  I've marked the ends of the drop slot.
I couldn't find my angle gauge, so I resorted to some late night trigonometry to figure out 120˚.
Too bad I didn't remember this trick.

Then I used a 4" hole saw to put a hole in the center of the top for the outlet, and another 4" hole in outer portion for the inlet.  I used three pieces of #10-24 threaded rod with nuts and washers to clamp the polycarbonate sheet in the grooves between the top and bottom plates, after putting a bead of caulk into the bottom groove.  I fastened the overlapping ends of the sheet by drilling holes and putting some #4x1/2" pan head screws through and into a strip of plywood.  I added a strip of self-adhesive rubber weatherstripping to the dado that mates the top to the trash can, because any little leak into the space below the drop slot plate is a big problem for this type of separator.

I hooked it up and the first thing I tried was cleaning out under my table saw.  I have a panel installed in the bottom of my contractor's type saw as part of the dust collection setup.  It accumulates a lot of dust and chips, and I stuck the hose in there and vacuumed it all up.  Just like a cyclone separator, it swirled against the clear sides in a downward spiral, and then dropped into the slot.  Pretty cool.  Only a layer of fine dust accumulated in the dust collector bag.  Here's a video.

Update:  I've been using it now for a couple of weeks, and it does just what I want it to do.  I've filled the trash can a couple of times and very little has made it to the dust collector bag.  I built this pretty fast, just to test the concept, and there are a couple of things I don't like.  The configuration requires a lot of elbows, which adds bulk, makes the hose fall off sometimes, and the inlet elbow inside causes a lot of turbulence.  I'm sure a side-inlet version would work a lot better, but I've got actual projects to deal with for now.

Dust Hood for my Miter / Chop Saw

I take dust collection pretty seriously.  The fine particles are a health hazard, and it makes a mess anyway. So I've been rigging up ways to improve the dust collection of my tools over the years.  The chop saw makes a lot of dust, and it's tough to collect because it won't work with a bunch of shrouds and things near the blade.  I tacked together a very quick hood to help my dust collector capture most of what it generates.  After using it for a year, I think it works pretty well.  It's just three pieces of 1/8" lauan plywood tacked to a top and bottom trapezoid of 5/16" osb sheathing.  ie, I made it from scraps.  Dust collection is pretty effective.  With about 600 cfm of air being sucked into a port directly behind the blade, the fine dust gets captured pretty well.  Some bigger bits bounce off the hinge mechanism and are thrown around the room, but I'm less worried about that.  I've thought about making some kind of angled deflector to put on the saw to reduce that, but haven't got around to it.

Miter Saw Stand

I built it as a small rolling cart, with a bunch of storage below.  There are three small drawers in the top section, plus a flexible storage scheme I devised where sheets of hardboard slide in slots.  This makes very compact little drawers, perfect for bits and other small items.  The lower area has three larger drawers where I keep my cordless drills and small clamps.  Yeah, I've only put a front on one of the drawers and I'm using screws as handles.  I'm classy.

Storage Below 

I attached a plastic dust collector fitting at the bottom of the dust hood, then a short length of 4" hose, with a quick-connect on the end.  I attach the hose from my dust collector to each machine as I use it for maximum airflow.  I tacked a piece of plastic gutter screen over the opening to keep from losing chunks of wood and other large debris down the pipe.

Dust Collection

Building a Gate That Won't Sag

Here's a plan for a simple gate.  I've built two of these for my own yard, and one larger one for a neighbor. Despite his kids occasionally climbing on it, it has held up very well.  No special hardware or fussy joinery.  Just a couple of miter cuts and a little analysis of the physics of gates.

Cedar Gate in my yard

If you just attached two pieces of wood at a right angle, one vertical (a stile) and one horizontal (a rail), and put hinges on the stile, the rail can swing back and forth as a very simple gate.  It probably won't last too long, because all the weight of the rail is trying to twist the joint apart.

By installing a support at an angle between the base of the stile and the far end of the rail, you form a triangle, which is a very stable shape.  The weight of the rail is now supported by the angled brace and the top of the stile, and there are no forces acting to twist the rail-stile joint and cause the gate to sag.

You could theoretically get the same behavior from an inverted version, where the rail is low and the diagonal brace runs from the top of the stile down to the end of the rail, but now the ends of the brace are under tension.  Without special joinery (or welded metal fabrication) the parts will tend to separate.

So take that triangle and hang whatever kind of decorative stuff you'd like to on it.  In my version, I start with two rails, about 1/2" narrower than the opening you're putting the gate into.  Put them far enough apart that the brace runs at a 45˚ angle or higher with respect to the ground.  A short, wide gate is under much more strain than a tall narrow gate.  If the opening is very wide, you might consider a double gate, with one on each post and the latch in the center, but those have their own problems.

You can see how the wooden components form the rail, stile, and support from the diagram above.  When I build mine, I just put screws through the decorative pickets into the rails and support.  I don't actually join the support to the rail, and there is no framing member to form the stile, since the pickets serve that function.

Cleaning Paintbrushes with a Fork

After using a brush with water-based paint, I've found that the quickest, best way to clean the brush is with a fork.  Run a stream of water over the bristles while combing them with the tines of a regular dinner fork.  The tines split apart the gummy paint that accumulates up higher in the brush, and lets the water quickly penetrate into the bristles so the paint rinses out quickly and thoroughly. 
Once the water runs clear, give the brush a good shake to get rid of most of the water (I like to do this outside over the lawn), smooth the bristles into their proper shape, and leave it to air dry.

Bench Planter III: Seating

I had intended to buy bluestone (sandstone), basalt, or some other nice masonry product for the top seating surface of the wall, but Jackie was intent on using some sort of composite decking material, like we used on our back steps.  Stone would have been much easier in some ways.  Mix up some mortar and plop it down...  But since the surface was going to be about 12" wide on top of a 6" wall, there would be some cantilever forces to deal with, and mortar isn't the greatest for that.

After several evenings of head scratching, here's what I came up with.  It's simple, strong, and removable if we change our mind or damage it.  First off, I mixed up a small batch of mortar and put a smooth coat on the top of the wall, pitching it very slightly so water wouldn't pool and (especially) have cracks to freeze in and damage the masonry.

We had to drive to Tualatin to pick up three 16' lengths of gray composite decking, because stupid Home Depot quit stocking the stuff I bought from them for the back steps.  I cut them down to 12'-3" and saved the offcuts to build the sides.  The front bench was made from three pieces, two 5" and one 2-1/2" in the center.  I ripped 1-3/8" off either side of the 5-3/8" stock for the center piece, and ripped a little 3/8" ribbon off one side of the other two to get the 5" pieces, because I wanted to get rid of the rounded edges in the middle of the seat.  Ripping them was a challenge I solved by building an oversized plywood sub-base for my circular saw and clamping a scrap fence to that.

Then I cut 11" sleepers from pressure treated 2x4, fastening them at the ends and every 16" along the front of the wall with 1/4" x 2-3/4" flat-head Tapcon screws.  Some sleepers got two fasteners to resist the cantilever forces.  I've never been a fan of Tapcons.  They seem like they're made more for the contractor who wants to get it done in a hurry than for people like me, but they do work and I'm installing a lot of fasteners so if one fails it's no big deal.  I've also got more experience working with concrete anchors and have learned the importance of drilling a little deeper and especially of cleaning out the anchor hole.  Concrete dust isn't like wood dust.  It doesn't compact past a certain point, and if you leave any in the bottom of a hole, it can cause the fastener to seize up, so brush & blow out big holes with an air gun, or at least run the drill bit in and out a few times to extract most of the excess.  The 3/16" holes go pretty fast with my big Bosch rotary hammer.  I also am now the proud owner of a small impact driver (I got a Milwaukie drill / impact driver set last year), which makes driving these puppies a piece of cake.  Install a #3 phillips bit into the driver and put on your hearing protection!  Bbbbbbbbbbbbbt.  Done.

Use a mason line to get them all lined up

The decking was fastened to the sleepers with #7 x 2-1/2" stainless steel finish screws, pre-drilled and countersunk, of course.  I left a minimal 3/32" gap between the decking, to keep the appearance neat and easy to clean.

Shorter sleepers on the sides

The sides were built in a similar way, but with a narrower surface made from 5" wide and 2-1/4" wide pieces.  Three 6" sleepers were installed on each side, and one of the 3'-9" offcuts was ripped in half to make the narrow strip.  I used the long 1-3/8" strips to trim around the lower edge of the seat, hiding the sleepers.  It doesn't look perfect from all directions, because the ends of the decking show the ribbed bottom, but it's very solid and should hold up well to the elements.

the finished seating surface

I think an idea that would have been more fun would have been to cast our own concrete pieces, like building a concrete kitchen countertop.  With the right reinforcing and some cast-in attachment hardware, it would have been strong and stable, and we could have stained it whatever color we liked, or put a cast or embedded design in it.  Maybe next time!

Bench Planter II: Carpentry

A few days after building the wall, when all the structural masonry had some time to cure, we started on the rest of the construction.  My plan was to use two pressure-treated 2 x 10 timbers to build the back wall, supported by three 4 x 4 posts that would extend up to support a trellis.  I dug three post holes, 20" deep, for the three 4 x 4 x 10' trellis posts; one behind each end of the wall, and one in the middle of the bed.

Four 3/8" x 6" galvanized lag screws were used on each side to attach through the posts into the masonry, sandwiching the 2 x 10's.  I countersunk the heads of the lag screws 1-1/2" into the posts with a 1-1/8" forstner bit so that they'd be hidden and also so that the 6" screws would penetrate far enough into the masonry wall.  We held everything in place while I used a long wood bit to drill through the posts and boards, and then a 1/2" bit in the hammer drill to reach through and start holes in the concrete before removing the wood temporarily.  I used a hammer drill to install eight lag shield anchors into 2-1/2" x 5/8" holes in the back before fastening everything with the lag bolts.  The post holes were backfilled with packed soil, instead of pouring a concrete footing.  Everything feels extremely solid, but shouldn't be a nightmare to take apart if we need to for some reason.

We immediately went and got a yard of compost mix and filled the planter up.  I'm not sure that was a good idea, but I guess, worst case, we shovel it all out some time and adjust the structure.  The main thing I'm worried about is the wood back.  I think there should have been a plastic sheet liner installed between it and the soil.  It would help the wood last longer (even p.t. eventually rots), it would keep nasty preservatives from leaching into the planter's soil, and it would keep the soil at the back of the planter from drying out.  The drying issue may be a problem against the concrete, too.

Bench Planter Construction I : Masonry

After deciding for sure on a location and size, and testing out the plan by stacking up some blocks, we started by digging a shallow (6") trench for a poured concrete foundation.  I built forms from 2x4 material that were exactly the outside dimensions of the finished wall, and we filled them with 12 bags of concrete, sticking pieces of rebar in at some locations where the web holes in the block would be.

Ready for concrete

This isn't a "real" foundation, like you'd build for a house or other serious structure.  It doesn't go deep enough, and doesn't have enough rebar, but I think it will be fine for this project.

The finished foundation

The next day, I mixed up a bag of type-S mortar and built the wall from 6 x 8 x 16 concrete blocks.  I'd carefully laid out the orientation and spacing before even digging the foundation, so it went pretty quick.  Basically I just buttered everything up with mortar, set a block in place, and tapped it into position with a chunk of 2x4 until it was level and plumb, being especially careful with the corners and ends.  I scraped off any squeeze out as I went, and used it for the next block.

All mortared together

We then filled some of the empty cavities with concrete (all the re-bar containing ones and a few others in structural spots) and filled any gaps with mortar.

Filling the cells

Jackie then applied a skim coat of mortar to the entire outside face, and textured it with a plastic broom so that it matches the texture of our house's foundation.

Mortaring in the dark