"you don't want to buy a cyclone separator"

[Alan Schaffter]

First- start looking for another woodworking supplier- that guy knows diddly squat.

". . . .a standard dust collector with a large canister filter with a flapper to keep it clean and the air flowing. He said the flapper is designed to wear out, to prevent it from ruining the inside of the filter. The canister would give me the maximum CFM, whereas a cyclone separator would reduce the blower performance by ~35%."

There is so much wrong with what he said, it is almost criminal.

Personally, you are throwing your money down a hole if you put a canister filter on a standard dust collector without a cyclone or separator. Dust will start immediately clogging the filter and immediately start reducing your suction- that's why they put the flapper there in the first place!!! In the second place some of that dust will find its way deep into the pleats and permanently clog and reduce flow through the filter. Some can actually damage the filter. Finally, using any kind of mechanical filter flapper, and using it as much as will be needed without a separator, will quickly destroy the filter media. It will actually force some small AND large dust and chips against and into standard media and can accelerate the de-bonding of any Gortex or other coating. The end result is that more and more dust will pass through the filter- you will be creating a "dust pump" AND the filter life will be greatly reduced!!!

The effect of a cyclone or other pre-separator on system performance depends on the separator AND the fan curve of the unit. My memory isn't as good as it once wast but I believe the numbers are roughly about 2 - 2.5" in. water impact on SP for a good cyclone and about 4.5+" for a trashcan or other pre-separator. Go to Cincinnati Fan or the Oneida website and find a fan curve for one of their non-cyclone systems, and see what effect 2" then 4.5" of SP has on CFM. Remember, unless you have a roll-around with a short hose, you'll also need to add the SP from hose, pipe, fittings, etc.

[henry blint]

Just have to keep an eye on the cyclone bucket. No way I would ever go back to no preseparator. I used a Thien style before I got my SDD. Cleaning the filter and bag in a dust collector with no preseparator is a huge pain. I do not recommend going without it. Not if you want to spend more time wood working than dust collector cleaning.

What HP blower do you have attached to it? And do you have the standard-size SDD or the Extra Large SDD?

[henry blint]

OK- I am fine with that. The "smell test" is that 35% degradation simply does not seem right. Sounds like a guy on a used car lot to me.

Also, Henry - your response introduces a new item that was not in your initial post. If , in fact, your driving concern is the $$ spent, then go get the Harbor Freight 2hp single stage. Or, better yet, Craigslist for used single stage - you will be out the door for a buck-fifty. Max. Probably closer to a c-note. It will do everything you need.

Bait-and-switch on your post, friend. I answered the questions you asked.

I thought it was clear I'm trying to find the sweet spot in price, performance, and portability, cobbling the system together myself, rather than just forking over the dough for an Oneida Mini Gorilla, say.
The HF 2HP doesn't have a 6" inlet, so it couldn't be used in a tower config with the SDD, and the CL asking prices for 10-year old systems have been ridiculous. I just sold an old but perfectly functional stainless steel equipment stand for $85 that sells new for $1200. These guys selling used dust collectors want $275 for late 1990s systems with 30-micron bag that sell for $425 new today with a 1-micron bag.

[Jason White]

A separator is total overkill if all you want is something you can connect to one tool at a time. Use the black plastic contractor bags; way cheaper than the clear ones made for DC's. I'd also forget about the pleated filter and get a shaker felt bag, instead. They don't wear out and some, like mine, filter down to 1-micron. My Delta unit is a 1-1/2HP model (that they no longer make), is ultra portable, and works just fine if I keep my hose lengths relatively short. I do think adding a separator will add a bit of friction loss, so the guy at the woodworking supply store is probably right. I don't buy the bit about the flapper being "designed to wear out." Also keep your hose diameter full size and reduce down at the tool (not at the collector).

I've been shopping for a single-tool, short-hose, small footprint, ultra-portable, dust-collection solution. I was thinking of putting together a small tower configuration on a shop-built rolling stand using a 1.5HP 850CFM blower mounted atop either an Oneida Super Dust Deputy (the new plastic one with 6" inlet and sloped ramp) or a no-name sheet metal cyclone available online. I don't have any metal cutting tools to try to make my own.

The tech guy in the dust collection department of a local woodworking supply store told me that I don't want a cyclone at all, that what I want is a standard dust collector with a large canister filter with a flapper to keep it clean and the air flowing. He said the flapper is designed to wear out, to prevent it from ruining the inside of the filter. The canister would give me the maximum CFM, whereas a cyclone separator would reduce the blower performance by ~35%.

So my questions are: 1) Does a cyclone really have that much negative impact on blower performance and 2) does a cyclone separator offer other benefits in addition to keeping the filter from getting clogged up?

[Bradley Potts]

First- start looking for another woodworking supplier- that guy knows diddly squat.

". . . .a standard dust collector with a large canister filter with a flapper to keep it clean and the air flowing. He said the flapper is designed to wear out, to prevent it from ruining the inside of the filter. The canister would give me the maximum CFM, whereas a cyclone separator would reduce the blower performance by ~35%."

There is so much wrong with what he said, it is almost criminal.

Personally, you are throwing your money down a hole if you put a canister filter on a standard dust collector without a cyclone or separator. Dust will start immediately clogging the filter and immediately start reducing your suction- that's why they put the flapper there in the first place!!! In the second place some of that dust will find its way deep into the pleats and permanently clog and reduce flow through the filter. Some can actually damage the filter. Finally, using any kind of mechanical filter flapper, and using it as much as will be needed without a separator, will quickly destroy the filter media. It will actually force some small AND large dust and chips against and into standard media and can accelerate the de-bonding of any Gortex or other coating. The end result is that more and more dust will pass through the filter- you will be creating a "dust pump" AND the filter life will be greatly reduced!!!

The effect of a cyclone or other pre-separator on system performance depends on the separator AND the fan curve of the unit. My memory isn't as good as it once wast but I believe the numbers are roughly about 2 - 2.5" in. water impact on SP for a good cyclone and about 4.5+" for a trashcan or other pre-separator. Go to Cincinnati Fan or the Oneida website and find a fan curve for one of their non-cyclone systems, and see what effect 2" then 4.5" of SP has on CFM. Remember, unless you have a roll-around with a short hose, you'll also need to add the SP from hose, pipe, fittings, etc.

BINGO! This is the first really useful, factual discourse on the topic. That woodworking supply store should be removed from your list of reliable resources. As Alan has noted, the canister filters come with significant compromises:

1) The bare impeller/motor combo moves a certain amount of air.
2) Every little thing that gets added to the inlet or outlet side of the fan is going to reduce its performance, and each of those additions has its own value that is literally subtracted from the original performance value -- these reductions are basic physics.
3) Filter media restricts airflow and therefore #2 above applies to it; greater levels of filtration subtract more and more airflow, which represents lost performance. That is why the cheapo setups include 5 & 30 micron filter bags -- they flow better than the filters that trap the really harmful particulates.
4) There is an optimum area of any filter media for a given air flow: Too much air coupled with inadequate airways out, and the particulates get forced into the media itself, which clogs, and ultimately gets blown to pieces and fails; too little air flow and the system just won't suck adequately. This is why the better levels of filtration need to be bigger so that there are more smaller airways (which are more restrictive) to adequately pass/exit the given volume incoming air from that fan unit.
5) Pleated/canister filters exist because they take up less space than shaker bag filters. They cost quite a bit more too. Before buying that canister filter, you'll have to decide just how important that reduced size actually is to you.
6) Canister filters clog far faster and easier than shaker bags, because those pleats concentrate and trap the dust laden air in very tight little pleated corners.
7) Canister filters are not easy to clean.
8) If you have enough room for it, the best value for performance is a 1 micron shaker felt bag. These take up a lot more space than the canister, but as the name indicates, only require that the bag be shaken in order to clean it. They are 1/2 the cost of the canisters, and can be custom configured at little to no additional cost so they will work with ducting that places them in more convenient locations.

As numerous others have stated, a separator is essential. If I were doing it all over again, I would buy a HF 1hp - 2hp DC (~650 cfm and as low as $99) + 1micron bag from Rockler ($25 on sale now) + a Dust Deputy (on a big can) and use a hose no longer than 6' - 7'. This would all be cart mounted and moved from machine-machine and should be able to keep a TS or planer clear. The cost of this healthy setup would be about $200. Ducting is the real hidden expense in DC systems, and my approach 100% eliminates it; plus if and when you tire of moving the dust cart around a big shop (jeez I wish I had that problem), then just add another one to the other side of your shop to ease the carting about and you will still be more than $1K - $2K richer.


-- Bradley

[daniel lane]

If I were doing it all over again, I would buy a HF 1hp - 2hp DC (~650 cfm and as low as $99) + 1micron bag from Rockler ($25 on sale now) + a Dust Deputy (on a big can) and use a hose no longer than 6' - 7'. This would all be cart mounted and moved from machine-machine and should be able to keep a TS or planer clear. The cost of this healthy setup would be about $200. Ducting is the real hidden expense in DC systems, and my approach 100% eliminates it; plus if and when you tire of moving the dust cart around a big shop (jeez I wish I had that problem), then just add another one to the other side of your shop to ease the carting about and you will still be more than $1K - $2K richer.

Bradley,

Are you thinking a "dust right" sorta-cyclone lid on a can, or the Oneida dust deputy mini-cyclone? I would have thought the dust deputy highly restrictive to a DC, given the small openings, but I've not used one.


daniel

[Jim Andrew]

Before you rush out and buy a HF dust collector, do a search on upgrading your impeller, there are many threads on guys trying to upgrade their HF impeller to get more cfm. Most of the discussion is changing to a Jet impeller. I have spent some time recently on Bill Pentz site, and he says you need at least a 15" impeller to have a healthy dust system. Mine is not that big, and I have been trying to figure out the least expensive way to upgrade.

[Chris Parks]

Before you rush out and buy a HF dust collector, do a search on upgrading your impeller, there are many threads on guys trying to upgrade their HF impeller to get more cfm. Most of the discussion is changing to a Jet impeller. I have spent some time recently on Bill Pentz site, and he says you need at least a 15" impeller to have a healthy dust system. Mine is not that big, and I have been trying to figure out the least expensive way to upgrade.

I am not allowed to link it but I have seen a generic 13" impeller modified by lengthening the blades with welded on extensions. Surprisingly it was a success but he was a good welder and knew exactly what he was doing. The dust extraction sub forum of the Australian woodworking forum has a ton of specific performance information and also a huge amount of hints and tips to protect our health. I think apart from Bill P's site it would have the most information and in a lot of instances stuff that BP has not gone into. Reading it is recommended.

[John Kos]

R2-D2.jpgThis is what I put together, we call it R2-D2. I have filled the silver can easily 10 times (3/4 full) and I have only cleaned the corrugated filter once. It never loses suction and works on everything from my ROS to the 13 inch planer. It's all good unless my wife decides she wants to fry a turkey and can't find her aluminum fry pot

[Mike Chalmers]

Before you rush out and buy a HF dust collector, do a search on upgrading your impeller, there are many threads on guys trying to upgrade their HF impeller to get more cfm. Most of the discussion is changing to a Jet impeller. I have spent some time recently on Bill Pentz site, and he says you need at least a 15" impeller to have a healthy dust system. Mine is not that big, and I have been trying to figure out the least expensive way to upgrade.

Really? 15"? Over reaction I'd say.

[Alan Schaffter]

There is more to it than just increasing the size of the impeller. There is a relationship between impeller size and CFM for sure, generally the larger the impeller the more CFM. Some manufacturers keep their impellers on the small side, sometimes for a good reason.

First, the impeller housing needs to be large enough. But, the big impact of a larger impeller is that while it is moving more air, it will draw more current. Put a 15" impeller on a 1.5 - 2 hp motor and you are likely to pull too many amps. If the breaker is too large and/or the motor doesn't have its own over-temp protection, you may shorten the life or burn up the motor.

[Chris Parks]

There is more to it than just increasing the size of the impeller. There is a relationship between impeller size and CFM for sure, generally the larger the impeller the more CFM. Some manufacturers keep their impellers on the small side, sometimes for a good reason.

First, the impeller housing needs to be large enough. But, the big impact of a larger impeller is that while it is moving more air, it will draw more current. Put a 15" impeller on a 1.5 - 2 hp motor and you are likely to pull too many amps. If the breaker is too large and/or the motor doesn't have its own over-temp protection, you may shorten the life or burn up the motor.

A little knowledge can be dangerous and as I said he knew what he was doing. I have also found some myths surrounding DE that do not stand scrutiny.

[Fred Thompson]

I have a Jet 1200 (12" fan) hooked to a Super Dust Deputy (SDD) and ran some cfm/fpm numbers using a Alnor anemometer Model RVA. The DC with a 6" 90 degree fitting measured 5700 fpm/1114 cfm from the pipe center.
The Jet DC with 6" flex running to the SDD sitting on a 55 gal barrel and 5 ft of straight metal duct measured 5800 fpm/1089 cfm. This leaves a total loss through all my hardware including the SDD was a whole 25 cfm. Therefore, the guy who said you would see a 35 per cent loss is not correct. I ran 35 gal of nothing but dust and found less than 1/2 cup of dust in my bag even after using the flapper.

[Fred Thompson]

This is my second post to your question, I misplaced the first one. I have a Jet 1200 with the Super Dust Deputy (SDD) and measured off the 6" inlet 5700 fpm/1114 cfm. After the SDD/55 gal drum/5 feet metal duct/5 ft of flex gave me 5800 fpm/1089 cfm. That is a 25 cfm loss through all that hardware. The guy who said you would see 35 per cent loss is wrong. I measured my with a Alnor anemometer model RVA.

[Michael W. Clark]

Fred,
Measure the system flow without the DD installed and see if you still get the same flow.
Mike