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

[henry blint]

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?

[Bill Bukovec]

I use a cyclone on my shop vac and I rarely need to empty the vacuum itself. So yes, it does keep the filter from clogging up.

i don't know if a cyclone has a negative impact on the blower performance or not. My gut feeling is if there is a negative impact, it's minimal.

Bill

[Kent A Bathurst]

May I safely assume that store does not offer any cyclone DC products?

I don't buy the line about the cyclone being inherently less efficient. And 35%? Doesn't pass the smell test.

On the other benefits:
1. You drop out the majority of the material without ever seeing the filter.
2. The cyclone, or 2-stage design, means that material that drops out also never sees the impeller. The 1-stage design draws everything through the impeller. More wear on that part - but this probably is not a big deal in a small home shop, except:
3. Chunks of wood, stray nuts & bolts, small rodents, etc. don't go through the impeller.

[Chris Padilla]

Two-stage definitely works! I once "accidentally" sucked a rather large, thick towel into my system. I feared it would wrap itself violently around my impeller and burn up my bearings and or motor despite turning it off ASAP. I found the towel completely intact in the dust bin no worse for wear.

[Wade Lippman]

I regularly forget the close gates on my Grizzly 3hp and it still has plenty of suction. Don't know if the cyclone reduces the suction or not, but since I have way more than I need, who cares.
Only reason to buy a DC is that space or money is severely limited.

[henry blint]

I regularly forget the close gates on my Grizzly 3hp and it still has plenty of suction. Don't know if the cyclone reduces the suction or not, but since I have way more than I need, who cares.
Only reason to buy a DC is that space or money is severely limited.

Your 3HP is a lot more powerful than the 1.5HP portable unit I'm contemplating, so you might not notice what could be a big deal for an 850CFM unit. Also, the fine dust has to go somewhere, since I can't vent outdoors, so I will need a DC with an exhaust filter in any case, even if I were to get a cyclone.

[henry blint]

I use a cyclone on my shop vac and I rarely need to empty the vacuum itself. So yes, it does keep the filter from clogging up.

i don't know if a cyclone has a negative impact on the blower performance or not. My gut feeling is if there is a negative impact, it's minimal.

Bill

I use a little Oneida dust deputy with my shop vac and it does work great. The shopvac's filter stays clean. I'm just not sure of the cost-benefits of the cyclone for a system that has a self-cleaning canister filter.

[henry blint]

May I safely assume that store does not offer any cyclone DC products?

Not in the small portable price range. Only the big ones that are 7ft or 8ft tall.

don't buy the line about the cyclone being inherently less efficient. And 35%? Doesn't pass the smell test.

I'm not sure what the smell is. Could be that spending $200 on a self-cleaning canister filter is better than spending $200 on a small cyclone, if one has to choose between them because of budget.

3. Chunks of wood, stray nuts & bolts, small rodents, etc. don't go through the impeller.

This is probably for me the biggest value of the cyclone -- blower insurance. It's possible I could suck up a nail or a screw from the garage floor.

So the question in front of me is a) filter canister now and cyclone later, or b) cyclone with 1-micron filter bag now with upgrade later to a nice filter.

[henry blint]

Two-stage definitely works! I once "accidentally" sucked a rather large, thick towel into my system. I feared it would wrap itself violently around my impeller and burn up my bearings and or motor despite turning it off ASAP. I found the towel completely intact in the dust bin no worse for wear.

I believe it. I have one of the tiny Oneida cyclones, and it's keeping the shopvac filter clean, and I have accidentally sucked up a small rag that went into the drum, not into the vacuum.

[Prashun Patel]

Despite the theory that cyclones and the like keep filters clog free, in my experience, it's easy to overfill the preseparator, or to suck down something that clogs the funnel hole momentarily. In either of these cases, everything then starts going to the filter until I realize what I've done. Do this enough and it becomes necessary to clean the filter. So, having an easy means to clean the filter is a good thing in any case.

[glenn bradley]

A cyclone does put quite a hit on your system. Cyclone systems are designed around this whereas adding a separator just adds an unexpected hit of some degree. I have overfilled my bin once and that was enough. A flapper will get the filter sorta clean but, a cyclone will prevent this in the first place (unless, like myself and others, you overfill the barrel ). If I did not have to breathe my return air I would use a bagger and just vent outside. I would not want to go back to a bag only or to a filter cartridge without a separator. As to how a separator will impact your current system that is not designed for one, it will. The impact versus the benefit is up to you. If I were getting a new system and had to breathe the return air a cyclone would be a must. My current setup is a cyclone for everything except a jointer way over in the corner. This machine uses an old bagger with a large AFF bag on top and a solid bag below. Eventually this will roll into the cyclone plumbing.

[Mike Chalmers]

Despite the theory that cyclones and the like keep filters clog free, in my experience, it's easy to overfill the preseparator, or to suck down something that clogs the funnel hole momentarily. In either of these cases, everything then starts going to the filter until I realize what I've done. Do this enough and it becomes necessary to clean the filter. So, having an easy means to clean the filter is a good thing in any case.

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.

[Michael W. Clark]

This is probably for me the biggest value of the cyclone -- blower insurance. It's possible I could suck up a nail or a screw from the garage floor.

So the question in front of me is a) filter canister now and cyclone later, or b) cyclone with 1-micron filter bag now with upgrade later to a nice filter.

I agree on the cyclone keeping big pieces out of the fan. Another benefit is going to be emptying the dust bin under the cyclone should be much easier than the bag arrangements on most baggers.

If the cyclone is doing its job, it does cost you in pressure drop, which takes more power to overcome or it will reduce the system flow (your choice). The separator on the bagger units probably has a pressure drop too, but I would imagine it is much less than a cyclone pressure drop. If you put the small cyclones on a shop vac, you don't notice a difference in performance because the shop vacs are rated probably close to 100"wg+ of static pressure. The cyclone pressure drop is a small percentage of this. However, for a centrifugal fan that only has maybe 15"wg of available SP, then the cyclone drop is a bigger percentage. Plus, the shop vac fan and centrifugal fans are completely different with differen performance curves.

You can put a bag filter on the outlet of the cyclone, but not sure how you would clean it without removing it, assuming you are blowing dust from the inside to outside. If you put it in a box, then blow dust from the outside to the inside of the bag, then you could clean the bag and the dust would fall into the box (check out industrial baghouses). The cartridge filters for hobby use open on the bottom to remove dust when you clean it by blowing from the outside to the inside.

[Kent A Bathurst]

I'm not sure what the smell is. Could be that spending $200 on a self-cleaning canister filter is better than spending $200 on a small cyclone, if one has to choose between them because of budget.

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.

........in my experience, it's easy to overfill the preseparator, or to suck down something that clogs the funnel hole momentarily....

That is what is called a "management problem".

[Jim Andrew]

I have a 2hp cyclone, and overhead dc on both my tablesaws. Sometimes I notice a strip of wood I'm cutting off the edge of the board go whizzing up the hose. Sometimes I hear a block rattling along in the piping. So just 2hp is enough to grab pieces of wood off your saw. When I dump my barrel, sometimes I find lots of small pieces. So the cyclone does keep all that stuff out of your impeller.