Cyclones – What am I missing?

[Frank Drackman]

I see that many people upgrade their single stage dust collector to a two-stage by adding a cyclone to the system. After reading many posts and watching You Tube videos the two benefits that I see are that it is easier to dump the chips and cleaner filters, but these improvements are traded against the loss of CFM. I also see that most people think that the ability to collect dust is limited by the CFM of the system.

I have thought of upgrading my 13 amp, 230v canister & bag system but I only see the single benefit of a cleaner filter. My bag is easy to dump, and is clear, so I don’t have to worry about overfilling or making a sensor to notify me when it is full. It doesn’t make sense to me to trade-off having to keep my filter clean vs losing CFM.

What am I missing?

[Doug Garson]

I think what you are missing is that a dirty filter reduces CFM. I don't have a cyclone but I have Thien baffles on both my shop vac and dust collector. I notice it more on the shop vac but I'm sure it happens on the DC also. Before the Thien baffle my shop vac filter would plug in a few weeks and CFM would be reduced and at least once to the point where the motor would overheat and die. With the baffle, the only time I notice reduced CFM is if the container under the baffle overfills and plugs the baffle and the filter gets dirty.

[David Kumm]

The bag needs to have enough surface area and the ability to surface load so the dust cake doesn't cling or clog. If you have large enough bags and the chips and dust easily drop off, their is little benefit to the cyclone. The cyclone allows for smaller filters and the use of cartridge filters that tend to be difficult to clean. A cyclone is also a benefit when direct venting to keep the crap contained rather than blow it to your neighbors. Adding a cyclone to a small system is counter productive as they do reduce cfm. The better they filter, the higher the cfm loss. Dave

[Frank Drackman]

I think what you are missing is that a dirty filter reduces CFM. I don't have a cyclone but I have Thien baffles on both my shop vac and dust collector. I notice it more on the shop vac but I'm sure it happens on the DC also. Before the Thien baffle my shop vac filter would plug in a few weeks and CFM would be reduced and at least once to the point where the motor would overheat and die. With the baffle, the only time I notice reduced CFM is if the container under the baffle overfills and plugs the baffle and the filter gets dirty.

I noted that in my original post. I fully understand that I have to keep my filter clean to keep optimum CFM but cleaning my filter is relatively easy. I set my compressor to 65 pounds and spray inward. The bag catches the dust.

It will be interesting to hear from others. Maybe I only think that I am cleaning the filter and really just moving dust around.

[Frank Pratt]

A cyclone will drastically reduce filter cleaning requirements. The Thien baffle works well, but in quantifiable testing (unlike most you tube tests), carefully weighting the results shows that a cyclone is superior, especially with the finest dust. And that's the stuff that clogs filters the worst and is hardest to clean from them.

Your blower must be 3 HP, which should move plenty of air.

[Dan Friedrichs]

The cyclone makes sense for a DC that's running all day long and moving a lot of dust - it keep the filters cleaner, longer. If you're only running the DC a few hours a week and blowing the filter clean isn't an inconvenience to you, then there's little point.

[Patrick Kane]

The main point of a cyclone is consistent performance. The single stage collector might move X CFM on day one, and within an hour of use might only move 80% of X. Without a separator, your filters take an unnecessary beating as well, which is why most of them come equipped with low quality bag filters. My $$$ cannister filter from Wynn doesnt get bombarded with jointer and planer chips constantly. It only ever sees small amounts of fine powder that is blown out once or twice a year. In that same year, I maybe go through 900 gallons of sawdust. In short, the cyclone prevents your filters from quickly loading and thus reducing CFM. Because of this point, you save time by not cleaning filters, and it allows you to use a better quality filter. You also have a lot more consistent DC performance. I cant imagine what a single stage collector's performance would look like while running a sander. You would be cleaning the collector's filter every 10-15 mins.

[Osvaldo Cristo]

The cyclone makes sense for a DC that's running all day long and moving a lot of dust - it keep the filters cleaner, longer. If you're only running the DC a few hours a week and blowing the filter clean isn't an inconvenience to you, then there's little point.

That would be my point also... and my practice.

[David Kumm]

Single stage collectors are what are generally used with a widebelt. Bags with a built in shaker or outside to inside cartridges with a pulse jet blowing inside to out are effective with fine dust. Inside to outside cartridges benefit from a cyclone but cyclones are not designed primarily for fine dust so they still won't be an answer for sanding. I run a cyclone with four Wynn cartridges for all but the large widebelt which uses a Coral four bagger with 8' singed poly bags. No way I'm running heavy amounts of fine dust into those hard to clean cartridge filters. Dave

[Jim Dwight]

If you don't mind cleaning the bags and have good ones that get the fine dust then I think you are fine. I hate cleaning the filters so I use a cyclone and discharge outside - no filters to clean. You might be different but most people loose more CFM from dirty filters than they would with a Cyclone.

[Stephen Bandirola]

I also use a cyclone and discharge outside without filters. If your dust collector is inside your shop and it is using filters it is pumping fine dust through the filter back into the air that you are breathing.
Discharging outside completely eliminates that (and there aren't any filters to clog or clean). There is absolutely no visible dust being discharged so its not bothering the neighbors.

[Ole Anderson]

One issue not mentioned is the performance of a good nano or HEPA rated filter vs a 1 micron bag. But they are way better than the earlier 10 micron bags. Also calculate the filter area of a bag vs a pleated filter.

[Jim Andrew]

I use a cyclone, and exhaust outside. Do have a filter for really cold days, and really hot days. The filter reduces the suction at least by half.

[Matthew Hills]

I use a cyclone, and exhaust outside. Do have a filter for really cold days, and really hot days. The filter reduces the suction at least by half.

Wow... that is much higher than I expected.

Which cyclone/filter are you using?
I thought these often came with pleated filters with very high surface area to minimize resistance.

Which tools does this make an appreciable difference on?

Matt

[Deb Clarkson]

L'm surprised no one mentioned all the chunks that beat against your fan blade without some kind of separator in front of it.

[glenn bradley]

L'm surprised no one mentioned all the chunks that beat against your fan blade without some kind of separator in front of it.


I run a cyclone and a bagger. I can relate to the bang/clang/sucking gravel sounds you elude to with the bagger. I use the bagger only on the helical head machines now; much quieter ;-)

[Brett Luna]

L'm surprised no one mentioned all the chunks that beat against your fan blade without some kind of separator in front of it.

That was an additional benefit of "cyclonizing" my DC...previously, the impeller screen was prone to frequent blockage when using the jointer, planer, or when cleaning up a lot of handplane shavings. Now it's not.

[Stephen Bandirola]

I run a cyclone and a bagger. I can relate to the bang/clang/sucking gravel sounds you elude to with the bagger. I use the bagger only on the helical head machines now; much quieter ;-)


I also use my dust collector as a general purpose shcp vac and am no longer worried about chipping or breaking the impeller..

[David Utterback]

For those who exhaust outside, is the noise level ever a problem?

[Tom M King]

Not with the nearest neighbors at least two dog barks away.

[Frank Drackman]

I would love to test a system without a filter that exhausted outside but living in Maine I don't think that it is feasible. I can't imagine what my heating bill would be during the winter.

[Stephen Bandirola]

For those who exhaust outside, is the noise level ever a problem?
No, not a problem. I’m in a regular residential neighborhood no louder than a regular built in house vacuum.

[Jim Andrew]

No neighbors except across the road, but I don't notice the noise, and my wife does not complain.

[Curt Harms]

L'm surprised no one mentioned all the chunks that beat against your fan blade without some kind of separator in front of it.

I guess that could be a factor if using a floor sweep but I use a dust pan for bigger chunks. I don't use the dust collector where larger pieces are involved, mostly jointer/planer, table saw and router table. None of those produce large pieces. The fan blades in most single stage dust collectors are fairly robust so I doubt small pieces would have much of an effect, maybe more noise than physical impact. YMMV of course.