J. Phil Thien's Projects

in regards to ducting, consider saving some footage by not running it up, over, and then down.  But instead, like how I did, horizontal at the same height of your baffle inlet.  My 6" HVAC ducting is 54" off the floor around 2 of my walls, while #3 wall is more dedicated to storage and misc, and #4 wall of my garage square is my roll up door.  So that is a total of...  30' length with only 1 45to45 bend that will be my main supply line branched off to 4 6"x6"x6" wye's and 2 6"x6"x4" wyes.  hay... it works :)  Does it get in the way?  nope.  And gave me a good reason to put a 30' long shelf above the ducting.

and wouldn't you know it....   you could hear the knot of wood in the video that is rattling around in the tophat which did NOT hit the impeller :)
To date, I have not used a bellmouth.  I do not think I will have a need to, even if it helps 2-5% efficiency.   It works perfectly so do not want to jinx it.

*** months later for an update ***

Wow...  this Thein baffle has done EXACTLY what it was suppose to do.  Have emptied out the blue barrel 6 times after being near 85% or so full.  Just this weekend, I installed 2 Wynn Env 35a filters and 2 clear plastic bags for my dual bag dust collector.  Which gave me a reason to empty my 2 old 30 micron (or maybe 20 micron?) original bags, there was about 6 gallons of brown looking sugar... oh wait... I mean fine dust. 
What a great first wood working project.  Learned alot about do's and dont's here on the forum and abroad.
a short video of baffle in operation:  https://www.youtube.com/watch?v=KmymX5WW88s
My lumberjocks project posting of the baffle: http://lumberjocks.com/projects/98274

Retired2... yes, I eventually put 45-45 elbows at each bend for the feed into the impeller.  Had to move my Grizzly back a little bit more but that's ok.

i could easily go back and install 45 adjustable elbow to another 45 adjustable elbow.    hmm.. i do have spare elbows.  i'll give it a shot.  the pieces are just duct taped together til everything is 100%, they i'll apply 'pookie' (as the HVAC call it) which is they grey toothpaste stuff.
i see alot of people use the 10' hose with even more severe bending.

98% finished.  sealing all done and tested aok with a handful of planer shavings.  still have to fine tune the outlet height and possibly add a bellmouth.
and yes...both bags inflate so i will not be blocking off one of the arms.

putting on my Super Internet Know It All Hat..  I couldn't see how this would work.  I believe the science and engineering behind the Thien Baffle (must be...  cool to have something named after you that is all over the world!) is the need of centrifugal force, balanced with gravity, balanced with friction against the wall, balanced with CFM. Well, looking at something nearby that is 4" in diameter around my desk... I would bet the CFM would have to be UltraLow, the arc cutout would have to be UltraThin, etc.   Think of a standard dust devil or dyson vacuum cleaner.  The debris does so many revolutions inside their chambers with no separation.  If you slowed down the CFM to lower those same revolutions, the suction pressure at the end of the hose would barely pick up a cat hair?

more progress.  I am also running a blog on this project over at LumberJocks so that other new person's getting into wood working can be inspired to do needed projects, especially healthy ones.
Nothing is sealed as I wanted to do a dry run.  Tossed a handful of planer shavings.  And from my eye, it looked like 100% shavings reached the bottom of the barrel.

JGT..  I "thought" my grizzly had a 7" inlet, as that is what I read all over the place (never measured it myself).  But, 6" inlet it is.  And you put your's up top...   I really considered that but concerned about the bearings being unhappy at horizontal instead of vertical, and couldnt figure out how to make my 2 arms out to the bags work without modifying the metal arms themselves.  You have a single bag on a 3HP?  and about using a 55gallon drum.  I am hoping to find a way to line it with a plastic bag so I can just wheel it straight out for the garbage truck.  Or...  lay it on it's side and slide it out.

I was going to purchase a 7" bellmouth from penn state..but has been forever out of stock.  might have to go the DIY bellmouth.  could you go into more detail about how you created your own?

I have over 4' of vertical clearance above my 55 gallon barrel.  I'm going with a 16" tall chamber.  But I did think what would happen if it went the full 4' high for a chamber :)

Phil...  after seeing alot of videos of the baffle in use, I always noticed stray debris accumulation where bottom lexan met wood with the use of a retaining lip for the lexan.  Figured, a 45 degree bevel from lexan on downward might help with that.  If anything else..  it looks sexy :)
And yes..  I redid the baffle plate as I found out I goofed my circular diameter by 1/2", which would of had the underneath weather stripping inside the arc cut out area.

Apple..  55 gallon plastic drum underneath with a 23" wide top.  I"ll later modify it so that I can somehow line with a 55 gallon trash bag and just wheel it out for trash truck directly.  Should be fun to see how many swirls in a 16" high chamber it takes.  Maybe I should put multicolor disco LED lights in the chamber.  Might be better than watching a fireplace some evening.

Thanks to all of those sharing their knowledge about different baffle designs, pro's and con's.  And special thanks to Mr. Thien himself and even Retired2 for which I have learned enough so far to think I can actually fly a little bit.
I started the first true wood working project over the weekend, which was a Thien Baffle attempt.  Here is my story:
1.)  3 HP grizzly dual bag dust collector (will find out if the baffle can handle 3HP or not soon enough).
2.)  baffle chamber will be 16" tall, with 6" circular spiral duct squashed down to 8" x 4.5" inlet, 7" outlet with bellmouth (whenever Penn State gets one in stock)
3.)  1/2" MDF with 1/8" hardboard.  Middle baffle plate will be recessed 1" under the 1/8" hardboard.
4.)  sitting on top of a 55 plastic barrel.

I think because I just registered, I can not post pictures.  I'll do so later.  Basically, I think I failed engineering right off the bat.  My cut out for the baffle, I think, starts TOO early which makes the end of the cut out end TOO early as well.  The end of the arc is not 1" or so from the inlet...but 7" or 8" before the inlet.   Not sure why this did not sink in during the rough draft with pencil layouts.
How critical is the position of the cut out arc, beginning to end?  I did a quick google image search and found other's also have done this and they say everything is AOK.  Would like to know now while I have opportunity to start from scratch.
-eric