Cyclone Clogging at the Cone and 7" Flex Hose

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Forum topic by pintodeluxe posted 01-31-2017 05:46 PM 1932 views 0 times favorited 19 replies Add to Favorites Watch
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5983 posts in 3319 days

01-31-2017 05:46 PM

Topic tags/keywords: penn state psi cyclone penn state cyclone psi clog cyclone clogged cyclone clogging cyclone clog flex hose clogged flex hose clclogging flex hose cyclone dust collector clog yclone dust collector tempest tempest clog tempest clogging tempest clogged

So I am running a 2 hp PSI cyclone with 6” mains and drops, and 4” pipe to the tool. On all tools but one, the dust collection is really quite good. Separation is good as well.

With extended work at the planer, I notice that the cone of the cyclone clogs up. If I don’t catch it right away, the whole 7” flex hose will back up. It is a Dewalt 735 with helical head. It is only a problem with wide boards or extended use. It just seems like the chips aren’t falling out of the cyclone action. They just stay in the cone and swirl around until they ball up and clog.

The 55 gallon drum is not over-full. I usually fill it half way before emptying it.


1. Leaks around 7” flex hose.

2. Leaks between plastic bag liner and drum lid.

3. Leaks around plexiglass window.

4. Internal blower on 735 planer is somehow altering cyclone dynamics.

5. Try opening another upstream gate to increase air volume to the planer.

6. This particular port starts as a 6” main, has a few feet of 5” drop, and 10’ of 4” flex hose. This way I can pull it away from the wall for easy setup. The Planer is probably 20’ from the dust collector.

7. Plastic drum liner partially blocking inlet to chip bin? Try running without plastic drum liner?

Has anyone experienced or solved this issue with a clogged cyclone cone or clogged 7” flex hose? I will do some checking tonight, but interested if anyone has encountered this issue on a 2-3 hp cyclone. It honestly surprised me because although I was working some 12” wide white oak boards, I was only taking 1/32” off per pass.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

19 replies so far

View WhattheChuck's profile


367 posts in 4066 days

#1 posted 01-31-2017 05:54 PM

All my planer clogging problems always reduced to the grounding wire running down the ducting. So I took it out, because the run was short.

-- Chuck, Pullman, WA

View pintodeluxe's profile


5983 posts in 3319 days

#2 posted 01-31-2017 06:01 PM

Thanks Chuck. Yeah that makes sense to get a clog in the hose due to a grounding wire. Since my main line is metal, there aren’t any wires to deal with.


-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View Manitario's profile


2781 posts in 3389 days

#3 posted 01-31-2017 06:13 PM

I have a 5hp cyclone and although I’ve never had any trouble with blockages, I have set it up enough times to identify potential trouble areas. I think that you have some good ideas already about potential causes of your clogging. In my experience, any air leak b/t the drum and the cyclone kills the efficiency. I’d be very careful to make sure that your drum is well sealed (I used a lit incense stick) and the drum to cyclone connection is sealed completely. I also don’t use a collection bag b/c I found that unless I had something holding it down, it’d get sucked up and impede the flow of chips into the drum. If you don’t have any leaks, then you could try having a longer piece of flex tube b/t the cyclone body and collecting drum; I find with short connections some of the chips get pulled back into the cyclone. The other potential issue that could be affecting you is that you simply just don’t have enough airflow; 10ft of 4” flex is a huge increase to the overall static pressure of your system and a huge hit to the CFM. I would have 6” duct to as close to the machine as possible and then a very very short run of 4” flex or even 6” flex with a 6 to 4” reducer right at the planer.

-- Sometimes the creative process requires foul language. -- Charles Neil

View EarlS's profile


3085 posts in 2854 days

#4 posted 01-31-2017 06:19 PM

I wonder if the positive pressure generated by the planer fan is messing you up. I recently had issues with my dust collector and re-vamped the whole thing to include a thien baffle and a garbage can collector only to realize after all of that work that the fan on the planer (Dewalt 735) was pressurizing a fair portion of the system. The little fan on the planer was powerful enough that it actually lifted the garbage can separator lid.

“So what” you ask, you have a cyclone and I have something else?? I would take a hard look at whether the system is under vacuum or pressure at the cyclone. I think the planer fan is messing things up. You might have to install an intermediate garbage can collector to balance things out. beyond that, more pictures of the setup would be helpful as well.

-- Earl "I'm a pessamist - generally that increases the chance that things will turn out better than expected"

View pintodeluxe's profile


5983 posts in 3319 days

#5 posted 01-31-2017 06:29 PM

Thanks- some good things to check. Much appreciated. My cyclone is pretty nearly to the ceiling, so unless I went with a 30 gallon drum, there isn’t any way to lengthen the 7” flex hose.

Thank you too. That was on my list of concerns too. I remember when I had a 1hp dual bag collector, and turning on the planer would puff up the bags like a balloon. I know the fan can have an impact, I’m just not sure how to fix it yet. Incidentally, I once removed the fan assembly from the planer to see if it would reduce noise. It didn’t make any difference so I put it back on.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View pintodeluxe's profile


5983 posts in 3319 days

#6 posted 01-31-2017 08:02 PM

Another thought came to mind… the planer is used differently than the other tools. I tend to start and stop the D.C. more often with other tools, but the planer runs for extended periods with the D.C. on.

Maybe it’s not the planer setup in particular, but just how I use it. The jointer may have the same problem if the D.C. stayed on so long.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View RobS888's profile


2608 posts in 2351 days

#7 posted 01-31-2017 09:18 PM when you turn off the DC the stuff in the cyclone falls down, just usually too little to plug it up. No idea except turning off the DC every few passes to let the (potential) plug fall.

-- I always knew gun nuts where afraid of something, just never thought popcorn was on the list.

View bigblockyeti's profile


5961 posts in 2226 days

#8 posted 01-31-2017 09:32 PM

Do you have a damper that could be slightly closed at the blower exhaust to slow air in the cyclone allowing the chips to fall out of suspension? It would be a trial and error effort as you still need enough velocity in all three suction line sizes to keep the chips moving and not just change the location of the clog.

-- "Lack of effort will result in failure with amazing predictability" - Me

View sawdustdad's profile


379 posts in 1391 days

#9 posted 01-31-2017 09:32 PM

If you can’t sort this out, you might try using a 30 gal trash can separator next to the planer, so only fine dust goes to the DC.

-- Murphy's Carpentry Corollary #3: Half of all boards cut to a specific length will be too short.

View clin's profile


1066 posts in 1502 days

#10 posted 01-31-2017 10:26 PM

I have a small cyclone (Dust Deputy), and I’ll notice larger, more massive things like large chips, will just spin and spin.

I think what happens is the centripetal forces, created by the spinning, force it against the cone and the angle of the cone is such, it creates a force trying to lift the chip. If this is more than gravity, the chip won’t fall. Since it seems to stay put. It also appears there’s a balance point. Probably as the chip goes higher, it slows due to the larger radius. As it slows, the centripetal forces drop.

Since these forces are greater for faster spinning, and faster spinning is from faster air, I think you may need to slow the air down. It may be that the extra push from the planer blower is the difference.

You probably can’t restrict the airflow going in, without risking a clog at that point. But, perhaps you could restrict airflow on the output side of the cyclone or even the blower exhaust. Or perhaps you can figure out a way to run the blower slower.

-- Clin

View Hammerthumb's profile


2956 posts in 2481 days

#11 posted 01-31-2017 10:47 PM

You have probably thought of this, but grab a bunch of the planer chips and try to vacuum them up directly from the hose that goes to the planer. This will eliminate the planer blower from the system. If it still clogs, then it must be from another issue that the planer blower.

-- Paul, Duvall, WA

View Nick424's profile


120 posts in 1146 days

#12 posted 02-01-2017 01:14 AM

I believe your problem is the distance between the bottom of the cyclone and the barrel. On the 20 HP ones we have at work the maker wanted the drum as close to the bottom of the cyclone as we could get. We have less than 6 inches of 14 inch hose between, just enough to raise the lid up and roll the 55 gal drum on its cart out.
As a test, raise your drum up on a standand seal it with duct tape (no flex hose) and see if that solves your problem.

View JBrow's profile


1368 posts in 1426 days

#13 posted 02-01-2017 01:34 AM


If there are no leaks and since the planer is a good distance from the dust collector and half this distance is 4” flex hose, my guess is that air flow is severely compromised. If so, then the large planer shavings slow down, lose downward/outward momentum, stick together, and form a shavings dam as the shavings approach the drum. The flex hose connecting the cyclone to the drum appears to be about 12” long, which could further slow the swirling air.

The easiest way to increase air flow inside the cyclone is to open another blast gate; in addition to the one at the planer. This may be all that is required to fix the problem since more air can enter the cyclone.

Additionally, increasing the distance from the planer back to the cyclone with larger smooth walled pipe could increase airflow within the cyclone. If this is not possible and then replacing the 4” flex hose with a smooth walled 4” flex hose could reduce static pressure and thus increase air flow.

Modifying the flex hose from the cyclone to the drum by inserting a length of smooth walled pipe and shortening the flex hose could also help. This modification may be enough to keep the air speed high enough to eject the shavings into the barrel.

As a point of reference, shavings and dust in my collection drum form an inverted cone where the shavings pile up around the wall of the barrel. My belief is that this is an indication of air flow within the cyclone and inside the barrel; the deeper the debris cone, the greater the air flow.

View pintodeluxe's profile


5983 posts in 3319 days

#14 posted 02-01-2017 03:07 AM

Great comments and ideas on this dilemma! Thanks to all for the comments. I checked for leaks at the flex hose and drum window. I checked the seal between the cone and body of the cyclone, and all were leak-free. I added some Rockler Extreme Tape for extra assurance, but that wasn’t the problem.

Then I tried opening a second blast gate. That made no difference except to swirl the chips faster. I tried partially opened gates, and gates in different physical locations, and they all behaved the same.

Then I pulled the plastic drum liner. I put the lid back on to collect chips directly in the drum. I fired up the planer and milled some more stock. Instantly the chips swirled and emptied into the drum as they should.

Whether the bag was causing a leak at the lid, or just interfering with the swirling dust, the bag was definitely the problem.

I checked the filter and cleanout and it was empty like normal. I think the planer showed the problem more glaringly because of the copious amount of chips.

-- Willie, Washington "If You Choose Not To Decide, You Still Have Made a Choice" - Rush

View bigblockyeti's profile


5961 posts in 2226 days

#15 posted 02-01-2017 03:46 AM

I have seen that some cyclone manufacturers are including a hose running from the side of the cyclone to the side of the dust barrel to keep the liner sucked tight to the inside of the barrel instead of flapping around. I think this well explains why this is becoming more standard.

-- "Lack of effort will result in failure with amazing predictability" - Me

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