Thien seperator

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Forum topic by Rasta posted 03-26-2010 03:19 PM 1679 views 0 times favorited 5 replies Add to Favorites Watch
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120 posts in 3464 days

03-26-2010 03:19 PM

Topic tags/keywords: question dust control

I just want to make sure I have this correct. If I was to build one of these for my 2hp harbor freight dust collector then I should use 6 in pipe going from the impeller to the center of the lid, then from the side of the lid to my ducting? I have been doing research on this for some time and just bought the dust collector, I read through Bill Pentz pages and just want to make sure I’m not mixing up all this info in my head.This morning I ordered my remote start for it on Amazon and am looking at the wynn filters, alittle confused about getting either the spun bond or the nano filter, any suggestions?

-- Roscoe in Iowa

5 replies so far

View Cory's profile


760 posts in 3441 days

#1 posted 03-26-2010 03:33 PM

Rasta: i used a 5” to 4” reducer from Delta and used the stock hose to my lid. The opening from the unit is sized to accept the 5” hose. I’ve seen mods where an adapter is used for 6” hose, though. Also, I bought the 80/20 filter from Wynn and I couldn’t be happier. Their “premium” nano filter is only another $60 or so, but it wasn’t worth it to me.

Good luck!

BTW: You can see my HFDC set up if you look at my projects.

-- The secret to getting ahead is getting started.

View Milo's profile


869 posts in 3341 days

#2 posted 03-26-2010 03:35 PM


I made a Thein separator using 4” pipes. I gave it a workout just after making it with some recovered pine I got off an old barn. The center pipe goes to you DC, the pipe with the angled outlet (the one with the 45 degree turn) goes to you tool. For me a planer and jointer. can’t help you on the filters though.

I blogged about it here:

Holler at me if you have any other questions.

Good luck!


-- Beer, Beer, Thank God for Beer. It's my way of keeping my mind fresh and clear...

View PurpLev's profile


8536 posts in 3670 days

#3 posted 03-26-2010 03:35 PM

yes you are correct

pipe from DC to center of separator
pipe from SIDE of separator to Ducting and tools

As for the Wynn filters – I got the paper filter. it costs less, and for my hobby needs will outlast my DC and has higher filtration which is really the more important factor for me. I blow it with low pressure air (~40psi) everytime I use my compressor (thats how I empty the air from the compressor). it does a fantastic job.

-- ㊍ When in doubt - There is no doubt - Go the safer route.

View dbhost's profile


5723 posts in 3254 days

#4 posted 03-26-2010 03:54 PM

IF you want maximum airflow / efficiency possible, you would go 6” from impeller housing to center of lid, and then a 6” port through the SIDE of the dust bin…

The HF DC is not designed for 6” duct though. There is no shortage of guys that have modded their HF DC for 6” duct on the intake, and at least one that I know of that went to 6” FROM the impeller housing into the inlet ring. That is way more sheet metal work than I am willing to do…

FOR NOW, my system is 4” in and 4” out, then stepped up to the OE 5” port on the DC. It has been working well for me, but is far from Bill Pentz approved. But from what I can tell from the way I understand what he has written up, Bill is taking an engineer’s approach and erring on the side of extreme caution…

There is a guy on Phil’s forum that is talking about swapping the HF impeller for a 12.75” impeller from Grizzly. Not sure if that would kill his HF 2HP motor, but it might be interesting to see how that works…

In the long run, I want to swap out my inlet to 6”, move the impeller housing up so that it runs straight into the inlet ring, and put my Thien, upsized to 6” duct right below it… Then go with a 6” main going to 6×6x4” Ys for the branches.

Honestly, if the pipe, fittings, hose, etc… were more commonly available, you would be BEST off, and working within the designed limits of this DC by using 5” duct and fittings…

On the Wynn filter options, call them up and talk to Dick Wynn if you can. He’s a heck of a helpful guy. FWIW, Bill Pentz recommends the Spun Bond Poly on his site, even though the paper has a better filtration rating. The way it was explained to me by some lady at Wynn, the difference in rating between the spun bond poly material, and the paper blend has to do with 2 different testing methodologies. Wynn recommends the spun bond if you do a lot of MDF and that sort of thing. Well while it’s not my primary material, I do machine a LOT of MDF, and hardboard, and… well you get the idea.

I have had my filter over a year now, and make a habit as I tun off the DC, I let it spin down, then I simply tap the filter 2 or 3 times each in spots every 60 degrees or so to knock down any dust accumulation. I finally had to empty the bag last week due to a jam I caused that made material bypass the baffle, and got a chance to look at the filter. Still looks brand spanking new…

FWIW, I have been processing a LOT of cedar recently, and after using the DC, and running the air cleaner (box fan with electro static filter) I can honestly say, that there is no cedar scent in my shop…. Now outside is a totally different story (guess where the shavings go?)

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View Rasta's profile


120 posts in 3464 days

#5 posted 03-26-2010 07:16 PM

Thanks for the info
dbhost- I am currently building aromatic cedar adirndack chairs and not smelling cedar after that is saying something. My plan is to build a shelter outside to put this dust collector in so I have very high hopes for a clean, dust free shop

-- Roscoe in Iowa

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