Thien Cyclone pre separator. Plastic 55 gallon drum.

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Project by dbhost posted 09-12-2009 03:54 AM 21553 views 20 times favorited 14 comments Add to Favorites Watch

Not much to say about this one. I have had a Thien Cyclone Separator on a 20 gallon trash can for about a year now hooked up to my Ridgid Wet / Dry vac. I made this quick and simple.

Materials list.
3/16” tempered hardboard scrap from the shop.
1/4” all thread, 10” long, 3 pcs.
1/4 – 20 hex nuts, 24 pcs.
1/4” fender washers 12 pcs.
4” S&D street elbow.
pipe nipple of 4” S&D.
Hot melt glue

Tools used.
Drill and twist drill bits.
jig saw with fine scrolling blade.
oscillating sander.
Hot glue gun.
Dremel and cut off wheel (I started with a 6’ piece of all thread).

This entire project took me an hour once I set my mind to it and did it.

I am listing this in jigs mostly because it is workshop stuff, not any other reason…

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14 comments so far

View Karson's profile


35300 posts in 5857 days

#1 posted 09-12-2009 05:01 AM

Cool modification.

-- I've been blessed with a father who liked to tinker in wood, and a wife who lets me tinker in wood. Appomattox Virginia [email protected]

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3589 posts in 4870 days

#2 posted 09-12-2009 02:13 PM

Thanks for sharing db.

How does it work?

-- Whether You Think You Can or You Think You Can't, YOU ARE RIGHT!!!

View dbhost's profile


5906 posts in 4688 days

#3 posted 09-12-2009 05:39 PM

I sucked up 30 gallons of cedar shavings / sanding dust with it as a test. I could not see ANY indication of any dust, even fine dust making it to the DC, it all stayed in the separator. It actually appears to work better than my 20 gallon version that is hooked up to the shop vac.

I can give a fairer estimate of function after a couple of months of heavy use, but for now, it is looking good. I definately prefer having the TS, jointer, planer etc… running from the dust collector instead of the shop vac… I can definately notice that the air in the shop, and the equipment are MUCH cleaner this way….

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View a1Jim's profile


118322 posts in 5034 days

#4 posted 09-13-2009 03:40 AM

Hey that thing sucks very well


View dbhost's profile


5906 posts in 4688 days

#5 posted 09-13-2009 04:11 AM

Ugh… I was wondering who was going to tell me this project sucked… I almost wondered if Phil was on here (Phil Thien the guy that came up with the baffle design)...

I am on the first full drum of sawdust, and just barely have a dusting in the bag of the DC. Less than 1/4 cup of material, and this is after knocking the filter down. (I don’t have a flapper, so I simply drum on the filter when I shut the DC down).

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View dbhost's profile


5906 posts in 4688 days

#6 posted 01-11-2010 05:19 PM

Not sure, I haven’t measured it, but the guy to talk to on those specifics would be Phil Thien. The designer / inventor of the baffle / separator. I CAN tell you from an unscientific measurement, adding the Thien AND the Wynn filter to my DC, it pulls a LOT harder than the stock DC… I am sure the Wynn had a lot to do with it, and I am relatively certain the Thien slows it down a hair, but the impact is negligible…

Phil is active on Sawmill Creek, and BT3Central (BT3Central user ID cgallery). I haven’t seen him here, but he is probably lurking…

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View Jimi_C's profile


507 posts in 4691 days

#7 posted 01-11-2010 08:57 PM

kunk: I’d love to see those readings in addition to some taken through different kinds of tubing, such as flex and 4”/6” PVC (as well as how 22.5/45/90 turns affect it).

-- The difference between being defeated and admitting defeat is what makes all the difference in the world - Upton Sinclair, "The Jungle"

View dbhost's profile


5906 posts in 4688 days

#8 posted 01-11-2010 09:00 PM

I wish these forums didn’t change formatting on us so I could do some text columns and rows to show you side by side comparison. So bear with the choppiness here…

Dust Dog pros. #1. Designed specifically for exact machine fitment instead of “universal fit”. #2. Built in Beater paddle.

Dust Dog Cons. #1. 2 micron filtration rating. #2. Cost (they are more expensive than the Wynn from what I have seen.

Wynn Pros. #1. “Universal” fit, meaning it is a bit more adaptable to a wider range of machines. #2. Spun Bond poly 1 micron filtration, paper blend and nano fiber .5 micron filtration. #3. Excellent “dust release” in the spun bond element. (I simply gently tap the filter, and dust that got to the filter simply falls into the lower bag, no paddle needed.

Wynn Cons. #1. “Universal Fit”. Some machines require creative fitment to get the Wynn to go on. This can be a pain. Also the look of the filter doesn’t exactly line up with the lines of many machines. Aesthetically they aren’t real pretty… #2. Lack of beater paddle. A lot of folks like these, and use them a lot… (See my comments above about tapping the filter down…).

With the better filtration, which is what a canister is about anyway…. I chose the Wynn…

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View dbhost's profile


5906 posts in 4688 days

#9 posted 01-11-2010 09:50 PM

Sounds like the priorities are in order. I am somewhat skeptical about air injection as I would think it would push generated dust away from the pickup point instead of driving it to the pickup point…

For now I am running 4”, but my long term goal is to run a main trunk of 6” to 4” drops…

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View bigike's profile


4059 posts in 4745 days

#10 posted 05-28-2011 02:16 AM

where did you get the drum from? and does it come with the clamp?

-- Ike, Big Daddies Woodshop, http://[email protected]

View dbhost's profile


5906 posts in 4688 days

#11 posted 05-28-2011 04:00 AM

I got it from byte container in backing Texas

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View splinter1000's profile


13 posts in 2939 days

#12 posted 05-06-2014 07:44 PM

Hi Dave,

I was wondering if you could help me out. From reading various ones of the forum topics, I think you have experience with both the Thein baffle pre-separator and the Thein baffle in-the-DC ring designs. I have a small shop that I am setting up a dust collection system for. I’m not too concerned about the static pressure loss associated with the Thein pre-separator, but my biggest concern is the added space it requires. As such, I’m tending toward the in-the-DC ring version. I purchased a new filtration canister fro the DC. My question is as follows : is there a marked difference in how much dust will eventually make it to the canister between the Thein pre-separator and the in-the DC ring versions, or is any difference marginal? I would expect that the pre-separator would be better in this regard, but I don’t know by how much.

Thanks in advance for any assistance!

View dbhost's profile


5906 posts in 4688 days

#13 posted 05-06-2014 08:16 PM

There really isn’t enough of a difference to matter. I went with the pre-separator for 2 reasons.

#1. Chunks hitting the impeller scared the tar out of me. Enough that I though it could potentially be a safety issue. It sounded very much like a small caliber handgun going off in my shop…

#2. The drum design is easier to empty / change than an integrated bag.

Having said that. I have given some serious thought to several design changes, and think the best, most space efficient design is the internal baffle. Second best / space efficient design is to “side flip” the impeller on a custom stand so that the impeller and separator ring connect directly, and the inlet of the impeller housing points straight down. Similar to what fellow Lumberjock Cory did…

I would put the stand part for the inlet / bag ring on a riser of sorts so that you could fit a Thien “Top Hat separator such as what Lumberjock revwarguy did in his project

That way you get the advantage of having an easily removable / empty dust bin, fewer bends, less flex line etc… in your setup, it takes up only a few more square inches of floor real estate compared to an unmodified dust collector,

This is in my long term project plan. I want to get rid of the 55 gallon drum and go with my 30 gallon steel trash can to save precious floor space anyway.

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View dbhost's profile


5906 posts in 4688 days

#14 posted 01-10-2022 04:10 PM

UPDATE, and I am changing my opinion of this for a few reasons.

First and foremost I still love the concept, and design for this baffle, and find that they work well in the DC ring itself, however ANY separator prior to the blower itself takes a hit on airflow to the system, and that hit can be just shy of 50%. Not worth the hit to me.

Likewise after converting this to a side inlet, I found emptying the drum to be a real chore.

I had moved the DC UP on a stand to allow the blower to be as close as physically possible to the outlet port on the Thien separator, I found this also put the DC bag clamp and bag at just the right height to make the bag changes easier.

So now the Thien 55 gallon separator is gone, to insure top airflow, with some separation / filter protection I am using a Neutral vane as recommended by BIll Pentz research page. It works, but requires me to clean the filter more often, which is pretty easy. just take the blow gun on the compressed air coiled hose just next to it, and blow it down…

IF I find the neutral vane allows the filter to get dirty. I will install a Thien baffle in the separator ring. Which I already have sized up. I WILL keep the neutral vane in there, but just add the baffle. I may do that before then just to have it done…

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