Cheap Cyclonic dust separator

[pilesofspam]

A little while ago this appeared on hackaday:
http://hackaday.com/2011/01/05/quiet-dust-extractor-from-scavenged-materials/
Since I'm in the middle of a woodworking project, I thought that I would make an attempt at creating my own cyclonic dust separator. I first looked at this:
http://store.oneida-air.com/dust-deputy-diy.aspx
Which reviews well, and would probably fit my needs (my needs are to stop my shop vac filter from clogging after a few sheets of MDF on the table saw). At $59, it's not overly expensive either. But I thought I could do better. What I came up with is in the picture. Note that This does not catch microscopic particles. I currently vent out the window, but I may add a filter system eventually. It LOOKS like clean air coming out, but those microscopic particles are really bad for your lungs, especially in indoor concentrations. In subsequent posts I'll document the build and results.

[pilesofspam]

We'll start by choosing a blower. I used a Toro PowerSweep that I had lying around not being used anymore. These list for $35, and if you look for a while you might find one on sale for $20:
http://www.toro.com/home/yardtools/blowervacs/51586.html
Next, I wanted to modify the top bucket to accept the blower. Pic below. The hole is cut so a chunk of 14" PVC can fit through and mate to the blower, and the whole thing is screwed together.

[pilesofspam]

That blower throws 170CFM, so the dust suction is a little better than the shop vac (rated 2.5hp peak) I was using. This equals about the airflow of what they call a '5HP' shop vac. the HP ratings, of course, are complete bunk, and really refer to current draw at locked rotor condition.

So- next step is to make your cyclone out of the 5Gal bucket. I just ran a shop vac tube in sideways and sealed it with a ton of RTV. Pics below.

[pilesofspam]

Now for the fun part. We got a blower (or a sucker depending on how you look at it) and we got a cyclone. Now we need a way to catch the sawdust once it falls and prevent it from becoming part of the airstream once it's settled.

So we modify our cyclone bucket with a giant hole in the bottom for a funnel. The funnel is a big gas/oil funnel I found at ACE hardware for about $3, and then I cut the neck off short to open it up a bit. Here's a pic of the funnel and the modified cyclone:

[pilesofspam]

Getting close to the end now. Our big 6gal bucket is the dust holder, but we need to modify the lid to accommodate the cyclone with its filter sticking out the bottom. Here's a pic of the lid modified, and a pic of the parts ready to go with it. I RTV'd the funnel into the cyclone, and rtv'd the cyclone to the lid of the dust holder. I then used a few 10-32 screws to hold the cyclone to the dust holder lid. The dust holder lid screws on to the 6gal bucket, so removal for cleaning is easy.

[pilesofspam]

That's pretty much it, you'll get a dust collector like the one in the first photo. It's loud, but not as loud as my cheapie shop vac, and I find it pretty effective. Just make sure you vent this outside or filter it, because of the microscopic dust particles mentioned above.

One more thing, I modified the blower slightly- I actually cracked off every other finger guard because I did not want to restrict the flow when I mounted the PVC pipe around it. Here's a pic. Probably not necessary, but I did it anyway.