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View Full Version : Introduction and Pentz Cyclones (Part 1)



Garrett in Cda
9th August 2004, 04:18 AM
Good morning

I'm a Canadian living in <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" /><st1:State><st1:place>Victoria</st1:place></st1:State>, on <st1:place>Vancouver Island</st1:place> on <st1:country-region><st1:place>Canada</st1:place></st1:country-region>'s west coast. I happened across your Forum, saw the interest in cyclones, and thought it might be helpful to post this saga on my construction and installation of one of the <st1:PersonName>Bill Pentz</st1:PersonName> designs (http://billpentz.com//woodworking/cyclone/index.cfm).

Because of the length, it will have to be posted in three parts:

A long discussion about Pentz cyclones on the Canadian Woodworking Forum earlier this year led almost 30 of us to decide to each build one, and some group purchases kept common costs down. Although there are variations due to people using motors and/or impellers they already had which in turn affects the diameter of the cyclone and the size of the inlet and outlet, the most common system has a 5 HP motor driving a 14" impeller housed on top of an 18" diameter cyclone. Some of us added one or two cartridge filters to remove any escaping dust larger than half a micron.

(Part 2 follows)

I had my cyclone fabricated in 20 gauge galvanized sheet metal by a local shop. At C$385 it just wasn’t worth the hassle of doing it myself. One group of 4 who built theirs together allowed afterwards that were they to do it again, they, too, would have the cyclone fabricated. Cutting the pieces out of sheet with a jigsaw is easy. Rolling and soldering the parts is not.

<img src="http://www3.telus.net/GLI/Cyclone/Finished%20copy.jpg"><?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
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One of the participants in Toronto organized a kit consisting of the motor, impeller, and impeller housing ( CNC router-cut Baltic birch ply for the matching top and bottom panels, the motor mount, and a couple of rings that attach underneath to provide a strong seat to the cyclone body). The precision is as good as on metal work. Inserting the 20 gauge galvanized into the tight, matching groove on the bottom was simple.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/1aaImpeller%20Housing.jpg"><o:p></o:p>

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Getting it into the groove on the top wasn't as hard as I anticipated. With the clamps only tight enough to apply a little pressure, it was just like putting a tire on a rim, i.e. push some of the metal into the slot, tighten that clamp and move along to the next section. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/1aClamps%20On.jpg"><o:p></o:p>

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The motor is mounted on a circular platen with hex bolts that pass through it into the face of the motor. (All holes were made by the firm that machined the housing components, and in every case the match among components was absolutely perfect.) The steel Sheldon Engineering impeller mounts on the Leeson’s arbor with a simple but effective clamping system controlled by 3 cap screws that either tighten or loosen the clamps. Once in place, the impeller drops through the hole in the top plate, and the platen sits flush in a recess rabetted in the housing top plate. Bolts - not installed in this photo - are passed through fender washers into Tee nuts supplied and installed in the top plate. I was concerned that their clamping action would be inadequate to prevent the motor mount from spinning, but they work very well and make installation and removal easy, given that the motor and impeller are quite a heavy assembly.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/Semi-assembled.jpg"><o:p></o:p>

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Here’s what it looks like inside with the motor mounted. (The tee nuts mentioned above are visible.):<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/1binside.jpg"><o:p></o:p>

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These are the cyclone parts from the sheet metal fabricator. They’re actually sitting upside down on the floor, so I’ve inverted the photo to show them in their upright position. The disk on the outlet pipe was to have been formed into an “air ramp”, a helix tacked-welded to the internal outlet pipe to direct the air in a downward spiral. After doing some further research, the performance reviews on air ramps were mixed with many comments indicating a poor installation would do more harm than good, and that it isn't needed at all in a well-designed cyclone. Thus, I decided not to install it, figuring I could go back and do so later if necessary. I didn’t.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/1Parts.jpg"><o:p></o:p>

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I puzzled over the stand for quite a while, and in the usual way, it was simpler and easier to build than to design. Some old bed frames supplied the angle iron, and the worst part of this job was grinding off the rivets to disassemble them. The cyclone has a small but strong circular ridge - shown in the photo above - where the cylinder is joined to the cone, and that provides a very handy flat rim to support the unit in a hole through a couple of pieces of ˝” plywood glued and screwed together that sit on the angle iron “shelf”. The hole is beveled to match the cone and is exactly its diameter. 3 small pieces of angle iron bolted through the plywood act as clamps on the rim to hold the cyclone in place.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/Cyclone%20STand.jpg">
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The plastic barrel needed a top which was simple enough to make out of some recycled ˝” ply with the edged beveled to match the barrel’s rim, and some closed-cell foam weather-stripping to ensure the seal. I use 4 inexpensive draw catches to pull it tight.<o:p></o:p>
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Garrett in Cda
9th August 2004, 04:19 AM
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Here’s a close-up of the 2 cartridge filters in an enclosure that enables the air to flow through them from the outside to the inside. Although one could eliminate the enclosure altogether by flowing the air from inside out, the manufacturer strongly recommends the opposite, since so much more filter surface area is available. It’s also much easier to clean them if it becomes necessary, even if other builders report that cleaning is a rare requirement. Note, too, that many builders have installed only one filter and seem to find it adequate. I chose this set-up for a couple of reasons. The extra filter ensures absolutely no back pressure on the system – which would impact disproportionately on performance - and an even longer cycle between cleanings.<o:p></o:p>

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Because the cyclone’s in the garage and evacuates an enormous volume of air from my basement shop, air must be returned to the shop to keep the house in balance. (I learned that lesson the hard way a year ago when I forgot to open a window. The DC sucked make-up air down a chimney in the adjacent rec room, and filled the basement with smoke from a smoldering fire. Cleaning up the resulting mess entailed a lot of work and expense, a mistake I'll not repeat.) For those in colder climes, this approach also prevents the loss of heat during the winter. Each filter has an 8" internal opening, perfect for my 8" ducting, so each filter exhausts through the bottom of the enclosure and connects to a ducting manifold that returns the clean air to the shop.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/5Filter%20Enclosure.jpg"><o:p></o:p>

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Although the design and construction details for the enclosure caused even more head-scratching than the stand, making it was quite simple. Serendipitously, I had a couple of sliding glass doors from an old kitchen cupboard that were exactly the right size, so I installed them in the front face frame to provide an easy visual check of the filters’ condition. <o:p></o:p>

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Unfortunately, installing it was tougher than it should have been, because I got the order of construction wrong, and the ductwork I’d already put in place partially blocked the way in. No problem, just slide it in diagonally and twist it onto the back wall, Brain freeze! A 36" wide x 16" deep box is too deep to slide diagonally into a 37" wide alcove. Moreover, it weighs about 90 pounds and is 48" high so it's really awkward to handle alone. In the end, I screwed a big hook into a rafter, wrapped a strap around the box, and used a small B&T to lift it tight to the ceiling. I managed to clear the duct and set it on a cleat I had screwed into the studs. Holding it in that position with a shoulder, it was possible to screw it into the side walls. A subsequent physical challenge was how to get the fourth bolt into the inside back corner of each rectangular metal filter base. Each base has to be drawn down to the floor of the enclosure in order to compress a large rubber O-ring gasket that seals the filter outlet from the interior of the enclosure. With only 3 corners fastened, the filters lean away from the unbolted corner and the seal is incomplete. I drilled the 6 easy holes one by one through both each metal base and the wooden floor, inserting a 1/4" machine screw before drilling the next. This way, the holes were a snug fit. <o:p></o:p>

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I had made the enclosure interior exactly the size of the filter bases plus a 2" space between them. Although I could just wriggle a hand between the filter and side-wall, several attempts proved the impossibility of getting tools into the area let alone manipulating anything. I ended up drilling the 4th hole in each corner from the bottom up, i.e. from outside in. After several fruitless tries with needlenose pliers to place the washer and bolt in the hole, a flexible magnetic pick-up tool worked like a charm. With no possibility to grip the bolt-head, I used a pair of pliers to hold the protruding end while I tightened the nut.<o:p></o:p>

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I installed a simple, sloping Vee-shaped diverter just in front of the inlet to split the air into 2 streams moving to the sides and down. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/4Filter%20Diverter.jpg"><o:p></o:p>

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I’m not sure how relevant the electrical circuitry is to your needs, since I forget whether your 220v consists of a single 220v leg or a pair of 110v legs as ours does. In either event some of which follows might be helpful. I installed a 30 amp 220v paired breaker to protect the 10 gauge BX (armored) 2-wire with ground. I wanted to be able to unplug the unit because I expected to have to spend some time tweaking the neutral vane and air ramp. (I didn't.) In any event, to keep costs down, I bought an inexpensive clothes dryer plug set consisting of a made-up cord with 7’ of #10 rubber-coated wire molded into a 4-prong plug, and the matching receptacle and box. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/Electrical.jpg"><o:p></o:p>

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I had previously installed a 50 amp “definite purpose contactor” as the basis of my hard-wired remote switching system for the 3 HP dust collector, and simply used it for the cyclone as well. The wiring is easy enough – the contactor has 2 side-by-side rocker strips, each with a screw terminal on each end, one pair in and one pair out. As well, there are a couple of spade terminals on the side to accept the output of a 12v transformer that actuates the contactor and closes the circuit. <o:p></o:p>

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Installing a contactor makes wireless remote switching really cheap. Woods makes the unit small square unit in the photo sitting under the contactor box. It’s activated by a small 2-button fob. Intended for household lamps, and it easily controls the contactor’s 12 v transformer with very good range. The cost was only $20, but the convenience is priceless. (Unless I misplace the fob.)<o:p></o:p>

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Since solid #10 wire is stiff, I made the box up on the bench. After determining the best layout and the location of entries and exits – 2 sets of #10, and 1 of 110v for the transformer whose wiring exits the box through its built in mounting pipe and ring – I drilled the holes and installed the components. With anti-shorts stuffed into the open ends of the armor to protect the wires, and a wrap of red tape on each end of every white wire that is hot, the cables were inserted into the box connectors and secured. The cables were then attached to the contactor, and the grounds twisted together and tucked out of the way. To complete the wiring, the transformer’s 12 v output was connected to the spade terminals.<o:p></o:p>

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Once the box was mounted beside the panel, I snapped the breaker into the panel and connected the hot white and black leads to the terminals on the breaker and the bare ground wire to the ground bar. (Note that the neutral bar to which the 110v white wires attach is NOT used in 220v circuits.) <o:p></o:p>

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The dryer cord has 4 pins but this circuit needs only 3: 2 hot and 1 ground. I used a multimeter to determine which wire connected to which pin. When used for a dryer installation, the red and black go to the two flat blades, the ground to the round, and the white to the L shaped pin. I snipped off the white where it enters the sheath, and hack-sawed its pin flush with the face of the plug.<o:p></o:p>

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After mounting the dryer receptacle box on the wall high enough to enable the cord to reach it loosely from the motor, but low enough so I can insert or remove the plug without a ladder, I wired the other end of the BX into the correct pins of the dryer receptacle.<o:p></o:p>

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Garrett in Cda
9th August 2004, 04:22 AM
The ductwork took the most time, and was the most physically trying. My original setup used an 8” plenum with 4” drops to each machine. The smaller pipe proved to be a major mistake as it really compromised performance. I kept the 8” plenum, but upgraded to 6” pipe to the major machines.<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>

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I made the blast gates out of scraps. Using spiral steel pipe rather than PVC creates a few problems. First, the pipe’s not perfectly round, and second it has a seam. That introduces voids around the joints that need to be filled with something – I used latex caulk because I had it - and taped. Not neat and tidy but works perfectly. OTOH, mating the pipe to the wood is easier than PVC. Just a few small nails hold it securely. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/Blast%20Gate%20sm.jpg"><o:p></o:p>

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<img src=”http://www3.telus.net/GLI/Cyclone/Blast%20Gate.jpg”><o:p></o:p>

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A circle cutter cuts the holes in the gates, and a single layer of duct tape in the sandwich provides just a little bit of clearance for the slide. When closed, suction seals the slide against the opening. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/Circle%20Cutter%20sm.jpg"><o:p></o:p>

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Since I was into it, I also fixed some other problems. My 20 year old Unisaw has a sloping interior floor that extends through a long, narrow slot under the motor housing through which the sawdust was supposed to spill out onto the floor to be swept up. In the previous DC installation, I rigged up a boot to cover the slot, but it wasn’t very effective. Moreover, the way the floor is installed, there are large openings in each corner which allow quite a lot of sawdust to spill out under the machine. Since everything is held in place with screws, except for having to be a contortionist, it was relatively easy to unfasten the floor, draw it back completely into the body of the saw, and to re-fasten it by simply increasing the tilt slightly. Some metal tape all around the interior perimeter sealed the bottom effectively. I then removed the metal cross-bar on which the extended lip of the floor had been resting – also fastened with screws – to leave an opening 6” high by the full width of the saw. Perfect for a 6” galvanized boot, with the rest of the opening easily covered by a piece of Masonite.<o:p></o:p>

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Connecting the extension table router to the Unisaw’s piping was also a bit tricky given the space constraints, but at the cost of a few scrapes and bruises I was finally able to achieve a tidy solution using a tee. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/6Unisaw%20Hook-up.jpg"><o:p></o:p>

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The jointer has a square chip chute came and with a plastic cover with a 4” DC connection. Too small. A piece of sheet metal now covers the chute and is cut out to accept another 6” boot.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/7Jointer.jpg"><o:p></o:p>

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Like the Unisaw, the Delta 15” planer has a long, narrow chip ejection slot. I had purchased the OEM DC boot, but it curiously provides a 5” DC connection, easily resolved with a 5” to 6” adaptor. (Note that this planer comes with a heavy plastic chip deflector installed internally that should be removed if a DC is hooked up to it. Instructions are in the manual.) Another error occurred here. I had, by this time, got so good at ducting that I installed solid pipe right into the planer. Only later when I went to use it did I remember that the planer head has to be able to move vertically. It was a simple matter to exchange the pipe with some flexible hose.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/8Planer.jpg"><o:p></o:p>

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Almost all bandsaws have the dust chute on the right side, the most perverse location possible, because the pipe or hose is always waiting to rip the unwary. In the photo below, you see a temporary door, because I’m experimenting with different locations. I’ve deliberately cut a lot of MDF to create as much dust as I can, and it seems to work well in the bottom left corner, and the only residue in the body of the saw is a small accumulation behind the bottom right front of the door. My next step will be to swap the panel 180° so that the hole is at the bottom right to see whether the hose interferes. I’ll probably also see what happens by increasing the pipe top 6” from 4”. As soon as I find the best combo, I’ll cut the hole in the original door and make the installation permanent by blocking the original opening on the right side. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/9Bandsaw.jpg"><o:p></o:p>

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Since I had purchased an extra 4x4” adapter for the original DC installation, I decided to retain and use it for connections to smaller machines. The Delta BOSS is still on its own because I need to buy a 1 ˝” to 2” hose connection adapter. <o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/11Turret.jpg"><o:p></o:p>

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The 6x48 belt / 12” disk sander is a dust-making nightmare. DC connections are difficult, but short of a shroud, the ones in the photo seem to do a reasonable job.<o:p></o:p>

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<img src="http://www3.telus.net/GLI/Cyclone/10Sander.jpg"><o:p></o:p>

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Looking Back: This was a very long and involved project spanning almost three months from start to finish. Some of the delays were due to travel and outside requirements. Others because I had to find and/or wait on materials or fabrication, or because there were days when I just didn’t feel like working on it. But, although there were frustrating moments, I never felt like giving up. Moreover, the fact that a group of others were also moving along at various rates of speed enabled lots of encouragement, information exchange, and problem solving along the way, despite the fact that most of us have never met in person.<o:p></o:p>

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Performance: this unit does a much better collection job than my Delta 3HP DC did. I’m sure most of that is due to the increase in pipe size from 4” to 6”. (The 6” piping flows 2.25 times as much air as the 4”.) However, there are other benefits. The cyclone takes up far less space than the DC; the barrel is a breeze to empty compared to the bags; it’s much quieter (a pleasant surprise) and the “quality” of the sound is more tolerable; and where the DC’s 1 micron felt bags used to leave a layer of fine dust all over the cars, the closed system and cartridge filters have eliminated that entirely. <o:p></o:p>

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For those contemplating this project, my costs in Canadian dollars not including sales taxes were:<o:p></o:p>

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Motor, Impeller, and Housing - $680 <o:p></o:p>

Cyclone (fabricated) $385<o:p></o:p>

Cartridge Filters - $152<o:p></o:p>

Stand and barrel – no cost<o:p></o:p>

re materials - $45<o:p></o:p>

Electrical including contactor - $156<o:p></o:p>

Blast Gates – no cost<o:p></o:p>

6” Galvanized Ducting & Fittings - $298<o:p></o:p>

6” Flex Hose & Clamps – 6 feet - $54 <o:p></o:p>

Shop materials (glue, screws, caulk, tape, etc.) - $30<o:p></o:p>

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All in except ducting: $1475<o:p></o:p>

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Everything: $1800<o:p></o:p>

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A final comment: I suspect most people who decided to purchase a commercial cyclone over DIY do so because the size of the project appears overwhelming. I can empathize with that perspective and would never suggest that buying ready-made is a bad decision. However, whereas the Pentz cyclone is well-researched and is adaptable to circumstances, there are more poorly designed commercial cyclones than well-designed ones, and the problem is that solid performance information is simply not available. Moreover, ducting the system is by far the most time-consuming and physically demanding element of the project and is the same job whether one buys or builds. Having the cyclone fabricated levels the field. Since the big expense in DIY - as always - is time, if you can afford it, I believe you get a system that offers superb performance and component quality for less money, and with power and capacity to spare for expansion.<o:p></o:p>

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Cheers, <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com /><st1:PersonName><SPAN style=Garrett</SPAN></st1:PersonName><o:p></o:p>

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PaulS
9th August 2004, 11:18 AM
Thanks for the story.

Wayne, I think that Garret deserves a certificate...

jow104
9th August 2004, 06:18 PM
SUPER ARTICLE

If I only had the time.

Al B
9th August 2004, 09:36 PM
Great work Garret Well Done :)

Pulpo
9th August 2004, 11:20 PM
I'm not sure what I'm more envious of the kit in the shed or the cyclone.

I'm not at the stage of building a blower now, but did some research and found it rather difficult to make one here in Oz.

I had the same problem Bill had [in the US] finding some impeller place willing to cater for the hobby market.

Maybe that's changed.

Yes great work.

But I'm just a novice in the extreme, the local guru Wayne should give the stamp of approval.

Cheers

Pulpo