Thread: Cyclone separator into open bag, no filters on external exhaust.

if only it was that simple.

Separation and the amount of suck you will lose from using a cyclone will depend on the overall cyclone design.

Poor design and matching will not separate fine dust well which may not be a problem for you.

However, if you just grab any old cyclone and cobble it up to any DC you will lose up to 45% of the suck (means you leave a lot of dust in the shed).

There is a reason the CLearvue uses a specifically designed and matched 15/16" impeller /cyclone and 4HP motor.
This minimises the loss of suck and what is lost does not matter.

Thanks Bob. Am I somewhere near about right to try for about 1000cfm at the machine? If so, and I'm using 6" everywhere, and assume a 50% loss through hopelessly mismatched components, then a suckyMotor of around 2000cfm might be close to about right in terms of suck? There is simply no way I can afford anything like the clearvu system so am happy to tinker and see what I can come up with. But just how much of a disaster it ends up being remains to be seen.

You don't say whether you're intending to have the blower before or after the cyclone. Dropping the dust/debris in to a flexible bag will only work if you can effectively seal the bag to the base of the cyclone AND you insert an internal frame in the bag to stop it from collapsing. I don't recall ever seeing any actual test data on suction losses due to cyclones, only the monotonously repeated 'up to 45% loss' figure. Yes I realise that this statement is probably a red rag to a Bob, I mean a bull.

Hmm, was thinking separator before the suckyMotor and the latter having an open exhaust. I'd need to experiment with the separator to see if it would get good enough separation and still eject the dust into an open bag without blowing it out of the bag or sucking too much find dust back out the exhaust.

That definitely won't work, the blower will just suck air through the cyclone orifice that offers the least resistance, ie. the debris outlet! The bag needs to be effectively sealed to the cyclone dust/debris outlet. Time for a rethink.

How about an 80L drum with lid instead of the bag?

Yes you can make that work. Some people use 200 litre drums, but I guess it depends on what sort of use you're expecting to make of it. If you search there's a member on here who makes/used to make cyclones for just the purpose you're intending, and if my memory serves me correctly he's located in NZ.

I have a cyclone outside my shed that empties the sawdust into a 20 gallon drum bin with the fine stuff just exhausting out below the fence line without a filter and it works fine. I use steel straps around some electrical conduits to hold plastic garbage bags open inside, and the top of the bag folds over the top of the drum before sealing with the lid, that makes emptying the sawdust easier. I just lift the strap cage out first then remove the plastic bag full of sawdust.

I did a post ages ago about it but they all disappeared in the big cleanup, so here they are again.

cyclone.jpg bin cage.jpg bin with cage in.jpg bin with lid on.jpg

Thanks for that dai sensei. It looks like a great solution in line with what I was hoping to acheive. I mean, why fuff about with a filter and micron bags if can get it all out the back of the shed and capture the lion's share of it. Is that middle plywood a thein baffle of sorts? What size is the fan inlet? How much dust ends up exhausted at the fence? Is there a thread somewhere that didn't get lost in the great purge, or can you please advise some dimensions, etc, if you can spare the time? I'm excited rather than daunted by it all now.

The thread is still there Upgrading my 1hp DC system but all the photos are gone. Initially I used my 1HP dust extractor, but by opening up the intake from the Cyclone to the fan, it ended up equivalent to a 2HP in suck. Eventually a 3HP dust extraction motor and fan unit attached. The cyclone was home made based on Bill Pentz's design (links in original thread) out of gal steel and plywood. Down the side of the shed I piped the pick-up system with 4 gates. Here's some more of the missing photos

100_0361.jpgnew 002.jpg

Not much dust is visibly coming out the outlet, certainly nothing the neighbours ever worried about. If it was a problem (though it never was so I never installed it), I was thinking of having another drum 3/4 full of water under the outlet, not connected so as the dust was pumped out it would collect on the water surface and then eventually sink.

I built a cyclone using Bill Pentz's website as a guide back in 2006, I just have the outlet hose poking through the side of the shed, no filter. I have never seen signs of any dust making it out of the hose.
I did have smoke coming out once when I was cutting some Dead Finish on the bandsaw and a fire started in my collection drum .

The build is documented here ( unfortunately the pics are all gone ) Bill Pentz even called in and posted a few times - the new cylone

I may still have some of the photos archived on a hard drive , if I can find a way to edit this old thread I will add some of the photos back in when I get time.

Thanks for the nod to Bill Pentz' website. I went there briefly earlier today and was blown away with the infor he has learned and shared. So many things to learn, so little time, but made time to donate to him just a little via paypal. Cheap at 5 times the price. Has anyone ever done a group buy of the sheetmetal parts or completed kits? Obviously freight would kill it for long distances but if a group of locals got together and made 5 or 10 of these in one hit...

Having read through much of Bill Pentz' website I went online in search of 3+hp blowers. The 3HP blowers seem to have about 12" impellers, rather than the 14" the site suggests. Anyone else noticed this?

There are some available with 14" impellers, generally made in Taiwan rather than China, and of course at a higher price. Off the top of my head I'm pretty sure Powermatic make one.

As to the idea of a group buy, well good luck herding cats! Yes. it can be done, but only with at least one person putting in an incredible amount of time and effort.