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DC vs Cyclone

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Forum topic by JCMeyersIV posted 08-21-2014 04:17 AM 916 views 0 times favorited 10 replies Add to Favorites Watch
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JCMeyersIV

75 posts in 1527 days


08-21-2014 04:17 AM

Ok so my old delta single stage just isn’t cutting it for me anymore and I’m looking to upgrade. I’m looking at two Grizzly models right now and I’m actually pretty confused about something. Everyone raves about cyclone DCs (the lagunas and coearvue) but the one I’m looking at pumps out only 750 cfm or so, verses the twin canister DC that sucks at 2300 cfm. If there a performance advantage? Or is the 750 of the cyclone collector somehow more powerful? What’s the deal here? Cuz the way I see it, if I go with the grizz, which I will, I’m paying less money for more suction.

-- John, NNY, www.facebook.com/JC4Woodworking


10 replies so far

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timbertailor

1591 posts in 886 days


#1 posted 08-21-2014 06:24 AM

Any DC that incorporates a cyclone or separator, is going to lose some cfm. Factory cfm ratings are whole nother discussion.

I am building my own from a Harbor Freight unit. Just got a .5 micron filter from Wynn Environmental. Buillt a Thien Baffle in about an hour and a half that sits in a garbage can.

You can find lots of good stuff on YouTube about the DC and the mods being done to improve performance.

-- Brad, Texas, https://www.youtube.com/user/tonkatoytruck/feed

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Loren

8300 posts in 3109 days


#2 posted 08-21-2014 06:47 AM

I have a 110v cyclone and a 3hp 2-bag unit pulling about
2200 cfm I think. Unless you’re willing to really commit
to a big cyclone… well, I think a cyclone should have
at least a 3hp motor. The 3hp blower on my double
bagger would turn my cyclone into a beast I think,
but as it is the 1.5hp blower on it is only
semi-effective. Sure, it helps keeps the shop somewhat
clean but it misses a fair amount. The double bagger
I use for my planer and sanding machines is way louder too.

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#3 posted 08-21-2014 12:00 PM

For the most parts, factory CFM ratings are about as accurate as the 6.5 HP your shop vac has. Good DC requires 1) lots of air flow, and 2) very good separation/containment of the debris from the air stream. A single stage can do this. Problem is the bag or filter will clog slightly with use, and reduce air flow. Enter the cyclone, a well made one (Pentz design) will separate the almost all the4 debris from the air stream before it hits the filter, so your filter (in theory) stays clean and continues to allow max air flow (requirement #1). Now, the cyclone also has some other advantages, it’s easier to remove the dust bin (usually) than a SS would be. Because the debris doesn’t hit the impeller, it can be (but not always is) engineered for better air movement like having swept back vanes and being made of aluminum. That’s a good thing because a cyclone also introduces a lot of drag to the air stream, so they normally have to have larger motors and impellers to generate the same air flow as a SS. But be aware all cyclones are not so well designed, on my Oneida I find I have to clean the filter way too much because the finest dust gets past the cyclone. BTW, having a kick-ass DC of any kind will be useless unless the ductwork can support it. Get a 5 HP cyclone and choke it down to a 4” flex connection and you are still going to get poor performance. The large units should have a 6” line running to the tools for maximum air flow, and if you don’t have tight filtration (1 micron or better) you’ll just be recirculating the finest dust back into your shop….unless you vent to the outside.

-- Our village hasn't lost it's idiot, he was elected to congress.

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English

517 posts in 939 days


#4 posted 08-21-2014 03:11 PM

Do you plan to keep the DC portable or are you planning on a fixed duct system? Most of the portable cyclone units on the market are on the small size, but you only need small if you are connecting directly to the machine in use with a 4” hose. 750 cfm capacity is plenty for one 4” hose. To pull 750 cfm though a 4” hose would require more than 15” of static. 450 cfm through a 4” hose is moving at 5000 fpm. 450 cfm will take care of all of the chips made by your machines. But if you are after the fine dust you will need a larger DC and either a 6” dust port on the machine or multiple 4” ports to move enough air to catch the fine dust. I have modified most of my machines to multiple ports and a few to 6”. I have enough room in my shop that my machines are in fixed positions. I have 6” duct run to each machine and either connect the 6” directly or wye it to 2 – 4” at the machine and use very short sections of 4” hose.

To solve the fine dust in the filter issue. I have installed a pressure gauge on my filters to let me know when they need cleaning, I also separated the filters by building a 2nd filter clean out base and installing a bullhead wye before the filters, this puts them in parallel. I installed a 6” blast gate between each filter and the wye. This allows me to close one gate at the top of one filter and open the re-circulation blast gate at the bottom of the same filter which reverses the flow through the filter and aids in the filter cleaning. I do this each day and my filter pressure readings are the same as they were when the unit was installed.

-- John, Suffolk Virgina

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JCMeyersIV

75 posts in 1527 days


#5 posted 09-10-2014 03:08 PM

Hey guys, sorry for the delay. I’m planning on the double model with CANISTERS not bags. And I’m thinking of upping to the next model up with cyclone (1200 cfm I believe) I really was just wondering which was better bang for my buck. I don’t plan on doing a bunch of runs. The cyclones appeal to me because they seem much easier to dispose of dust and chips and I’d get longer run time out of the bags than a single stage. I should have made that more clear.

-- John, NNY, www.facebook.com/JC4Woodworking

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JCMeyersIV

75 posts in 1527 days


#6 posted 09-10-2014 03:19 PM

Oh. I also hate changing the bags on my current DC. Seems like I’d be doing that less on a cyclone.

-- John, NNY, www.facebook.com/JC4Woodworking

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Loren

8300 posts in 3109 days


#7 posted 09-10-2014 04:42 PM

The filter clogs on my cyclone often. I can turn my
head and bang it around in a trash can to knock
the dust out of the pleats, but that’s still a messy
job. I’ve started using the larger DC hose to clean
the cyclone filter. That works well but of course you’d
need two dust collectors to do that.

I would prefer a baghouse filter for the cyclone.

I’ve seen claims that cyclones don’t need frequent
filter cleaning but my experience refutes this. The
drop in suction when the filter clogs (it happens
gradually too so it’s hard to notice) is substantial.

View Fred Hargis's profile

Fred Hargis

3932 posts in 1955 days


#8 posted 09-10-2014 04:53 PM

Maybe, maybe not. It goes back to a multitude of tings I mentioned earlier.

-- Our village hasn't lost it's idiot, he was elected to congress.

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English

517 posts in 939 days


#9 posted 09-10-2014 05:06 PM

So far for me cleaning filters is easy. I watch my filter pressure gauge. If the pressure reaches 0.5” I reverse the flow through the filters for 3 – 5 minutes. The pressure drops to 0.4” I’m good for another barrel or two of saw dust. I also clean them at the end of each day. 3 minutes per filter.

-- John, Suffolk Virgina

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buildingmonkey

242 posts in 1009 days


#10 posted 09-11-2014 12:41 AM

Loren, if your cyclone filter is clogging often, most likely you have an air leak in your system. I had that trouble, and the gasket was leaking between the blower and the cyclone body. I used silicone to seal it, took it apart and put it between, not just on the joint, but since then my system is greatly improved. Even when using the wide belt sander it doesn’t clog the filter.

-- Jim from Kansas

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