Almost a year after building a blower, I finally got around to installing my new system. It works great. After much research — primarily using this invaluable site: http://www.billpentz.com/ — and deliberation, I decided to build my own blower because I couldn’t find one commercially available that is single phase and more powerful than 2 hp. I bought the impeller and 5 hp motor from [email protected], and used the plans on Bill’s site to make a blower housing out of 1/8″ plate steel.
I decided to forego filtering the air and just blow it outside. This makes a lot of sense to me for several reasons. First, I have a small shop, so a cyclone and filters would take up a lot of space. Second, the cost is much less. Third and most importantly, it does the job of removing the fine dust from the ambient air (by flushing air out of the shop and replacing it with clean outside air) better than any other kind of system no matter how good the filtration. In fact, according to Bill’s site, the only way commercial shops can meet OSHA’s strict air quality requirements is by placing the dust/chip collectors outside rather than recycling the air within the shop.
The drawback, of course, is that the conditioned inside air has to be replaced with outside air (must open a window when the blower is running). So in the winter, it can get pretty chilly quickly. However, having a small space makes it easy to heat up again, and here in Boulder, CO we still get really nice 50+ degree days even in middle of winter, so there are really very few days when this is much of a problem.
All in all, I think it is a very cost-effective, space-saving system with superior performance. After using it for a few days, I’m surprized more small/hobby shops don’t do it this way.
The pics show the blower and the 6″ ducting I ran under the shop. I built an adaptor out of fiberglass to make the transition from the 5 1/2″ x 7″ square port on the blower to the 6″ duct. It sits in the space between floor joists and isn’t visible in the pictures. I aimed the outlet out the north end of the shop away from windows, so that dust isn’t sucked back into the shop. I haven’t finished making all the fittings for the other tools, so right now I only have it hooked up to the table saw. For now, I’m using 5″ flex hose because it fits snuggly over 4″ PVC/ABS couplers which are about 4 1/2″ I.D. I’m using these couplers to make dust ports for my machines.
Hope this helps others who might be considering a new DC system.
Replies
NBT
Great system! If you don't mind my asking, a few questions:
How loud is it?
How much did it cost?
How easy was it to construct the blower assembly?
Lee
It isn't as loud as I feared it might be. Certainly it's louder than the little Jet 1 hp unit it replaces, but not so loud that I'd want ear protection. Not nearly as loud or high pitched as a shop vac for instance. I also thought the vibration might be significant, but it isn't.
Cost was probably about $500. The motor and impeller were about $300 from Ed (a really good deal I think). And I probably have close to $200 in the other stuff -- ducting, hose, electrical, etc.
The blower housing wasn't too hard to build, but it wasn't real easy either. The plans are very straight forward. I chose to make it out of 1/8" steel rather than wood and sheet metal, as the plans suggest, because I wanted it to be strong enough to contain any possible disaster, like the impeller coming off the motor arbor. Not being real experienced in metal working, I found it a challenging project. Getting the piece that runs around the circumference bent properly was the hardest part. I used a press to get it bent roughly in the right shape, then various clamps and straps to cajole it into place as I tacked welded it. I'd guess that a professional welder/fabricator could make it in less than a day.
NBT,
Thanks for the reply. I like the idea of using the metal, but the welding part leaves me out in the cold.
Lee
You could get someone to weld it up for you.
Nice job. I'm fabbing a cyclone to use with a freestanding (for now) blower, and intend to exhaust it out my basement window. I'll probably put a filter stack on there at some point, with blast gates to switch between them, but I don't make dust that often and it doesn't bother me to send the air out*.
That's a good price for a blower wheel and motor. I thought he charged about $200 for the wheel alone.
*My furnace and WH are sealed power-vent types, with supply air also ducted in. I open the other window anyway when I use the exhaust fan, and I'll do the same with the DC when it's up and running.Be seeing you...
Dear North,
Nice, set up! After spending a few $ on my system, I am sorry that I didn't just exhaust everything outside, like you have done. A couple of questions:
1) Did you box in your PM 66? If so.... why?
2) Is the floor of your shop double 2x4s? That would seem pretty light for a cabinet saw.
Pretty cool set up though.
Best,
John
John,
1) It's not a model 66, it's a model 64 which is the contrator's version. I upgraded it by building my own plywood cabinet and turning the motor mounting bracket around and hanging the motor upside down off of it, so that the motor sits more or less directly under the blade. This way, I've fully enclosed the inards of the saw for better dust collection and made it more space efficient (my outfeed table is a tool cabinet). Also, the saw's center of gravity is more centered under the blade, so it's inherently more stable. It was a big improvement to the saw, and I highly recommend doing this to anyone. I've thought about posting pics of the saw here showing what exactly I did. Perhaps I should.
2) The joists are 2x10s. What you see in the pic are 1x2 rips stapled to the sides of the pressure treated joists with 1/4" plywood fastened on top of the rips. I did this before I sheeted the floor so I could lay in insulation batts from above and then put down the deck. Saved me a whole lot of grief : )
Dear North,
I like both of your ideas. I don't know if I completely get the mod that you did to your 64, but it sounds cool. A pic would be appreciated. I like your solution to the insulation question as well. Nicely done!Best,John
I'll try and get some pics of the saw up soon. Might be a couple of days before I get the chance. I'll probably repost under a new subject -- "contractor to cabinet conversion" or something.
I liked the insulation solution too. I just had to be carefull to keep the floor dry before the building was dried in. But I was framing in winter in Colorado, so it was easy.
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