A Thien Baffle tested on a shopvac

[Wade Lippman]

I have long been skeptical of the Thien Baffle. Though I am wholly ignorant of fluid dynamics, to my eye it seems as likely to keep the dust suspended as to make it drop. Many people are extremely satisfied with it's performance, but I haven't seen anyone actually test it. So I did.

I built setup identical to the one on Thien's website and tested it with and without the baffle in place to see what would happen. (The elbow I had on hand had a large radius, which resulted 4" between the baffle and the top, rather than Thien's 3". I doubt that matters, but wanted to mention it.)
I used a Dyson canister as a shopvac; it has near perfect separation (after six months of use in my shop the filter is still clean) so whatever ends up in the Dyson is what got by the test setup.

For media I used 3 gallons of debris from my JDS cyclone. Since some fines from the JDS had passed through and were lost, I added 3 cups of wheat flour to restore the balance. I built the separator out of the 5 gallon can that came with my Oneida Dust Deputy.

I sucked up the 3 gallons with the baffle in place and got 8 ounces of dust in the Dyson; about a 98% separation. I then removed the baffle and tried again, after mixing the 8 ounces back into the debris.
Without the baffle I got 3 ounces of dust in the Dyson. Repeating, I got 5 ounces.
Putting the baffle back in place, I got 11 ounces.

On the basis of these test it appear that both separated out essentially all but the finest debris. It would take more than 4 runs to determine which was better with the fine dust, but it is fair to say that the baffle was not significantly superior to no baffle.

I only got the bin half full (it was all the debris I had in my JDS) so I cannot comment on claims that the baffle is much better when the bin is nearly full.
I used a feed rate comparable to the one on Thien's website. Normal shopvac use would be much slower. I have no idea how it would affect the results; I simply didn't feel like spending a few hours feeding it slowly.
Most people seem to be using them on DCs. I don't know how meaningful my results would be to how it works on a DC.

I didn't test the Oneida Dust Deputy, but I have emptied it twice of mostly sanding dust since I got the Dyson, and less than an ounce wound up in the Dyson, so it is pretty good. And after all this the Dyson filter was still clean!

[Lee Schierer]

I don't know if it removes any more material, but on my set up with an older Delta DC sitting on a 55 gallon drum, the Thein baffle allows me to fill the drum to almost 3/4 full before sawdust fills the dust bag.delta.jpg Before I made the baffle, I could not fill the drum over 1/4 full without clogging the filter bag.

[Wade Lippman]

I would like to see you (or someone else) come up with a test to actually establish that. Without a proper test it could be a difference in the material you are putting into it, the humidity, or some property I'd never think of; or simply the placebo effect.

I suppose someone could suck up a half bag of debris and measure the air speed with an anemometer. Clean the filter, mix the dust back in, and try again without the baffle. A consistent difference in airspeed over a couple runs would tell if there was a reduction in filter clogging.
Well, something like that anyhow.

I would also like to see someone repeat my test.

[Phil Thien]

Wade had been over at Woodnet badmouthing my separator design for some time, without having actually made or seen one.

I called him on it a month or so ago.

He seems heck bent on "proving" it doesn't work.

A strange situation.

[George Bregar]

Wade had been over at Woodnet badmouthing my separator design for some time, without having actually made or seen one.

I called him on it a month or so ago.

He seems heck bent on "proving" it doesn't work.

A strange situation.

His response to Lee was telling...the vast majority like Lee are thrilled...and Wade's response "What are ya gonna believe, me or your lying eyes?" You steal his girl Phil?

[Bruce Wrenn]

To see the effectiveness of mine, google "Another Vote for Phil Thien's Baffle." Look at the pictures in the last post in the thread. The Minwax is a quart size can, FYI.

[david brum]

Wade, I haven't built the shop vac version myself. I have used the internal baffle on both a Jet 1.5 hp DC and a 3hp double bag DC. My test for efficiency is this: Without the baffle, my pleated Wynn filter would be caked with dust every time I emptied the collection bag. Sometimes the airflow would be so poor that I'd have to clean the filter between emptying the bag. After I built the baffle, my filter remained clean for months. This significantly improved the overall airfow and presumably the air quality in my shop. The only time I've since clogged the filter is after a long session using a 16/32 drum sander or if I've let the bag overfill. I still check my filter each time I empty the bag. Usually it is clean.

I've worked with maple, madrone, maranti, walnut, poplar,fir, pine and oak. I get the same results regardless of species with the exception of maranti, with it's nasty, abrasive dust. I don't see any difference is separation over seasons or temperatures.

Again, I can't vouch for the shop vac separator. The DC baffle works very well though. Definitely much better than without, probably as well as older cyclone designs.

[David Hostetler]

After the last 3 years with Thien separators, I find this test highly suspect. At the very least, This is NOT the sort of result I get with mine...

I am not going to bother with the scientific method here, but simply tell you, I use mine regularly. The shop vac model typically I have to clean the HEPA filter every 3rd empty of the trash can. The DC model I have yet to need to do anything more than knock the fines out of the filter after using the DC, this is after 2 years, and no less than 8 fill / empty cycles of the 55 gallon separator.

[Kevin L. Pauba]

My Thien Baffle has worked great on my shop vac since I built it soon after Phil described it and gave directions on its construction. I need no other proof ...

[Wade Lippman]

Wade had been over at Woodnet badmouthing my separator design for some time, without having actually made or seen one.

I called him on it a month or so ago.

He seems heck bent on "proving" it doesn't work.

A strange situation.

Phil,

Why don't YOU repeat my test as I described it above? If you do and find your baffle passes half the dust as the same rig without a baffle I will never mention it again. I will never post to a woodworking site again if that would satisfy you.
I only ask that you test it as I did and report the results. What can be more fair than that? In fact, I will make the same offer to anyone.

Since you haven't tested it, how can you be certain I am lying? Just to cover the one chance in a thousand that I am right, wouldn't a responsible person test it?

[Wade Lippman]

Without the baffle, my pleated Wynn filter would be caked with dust every time I emptied the collection bag. Sometimes the airflow would be so poor that I'd have to clean the filter between emptying the bag. After I built the baffle, my filter remained clean for months.

As I stated, my results might only apply to a shop vac with a fast feed rate. It might work as well as a cyclone on a DC. I don't know because no one has tested it.
I am glad you are satisfied with it, but that just isn't an experiment.

I have a friend (a chemist actually) who uses high octane gas because he kept records for years and found it gave him sufficiently better mileage to justify the higher price.
The gasoline companies and the auto companies say it is a waste of money to use any higher octane than the engine is designed for. Yet he has years of experience to the contrary. I am pretty sure he is wrong.
I do not doubt your sincerity or your intelligence anymore than I doubt his, but your experience is not proof; only a test is.

[Curt Harms]

I can't quantify my results either. I do know that with the same machine, same plumbing etc. I get virtually no chips in the canister filter with the Thien baffle. Without the Thien baffle I got a lot of chips in the filter. I do still get a little flour-like dust in the filter. I've never tried a baffle with my Fein vac. I just run a Genie bag & HEPA filter, don't see any advantage to a separator before the shop vac. Given the time & materials (leftovers mostly) to build it, the Thien baffle is the greatest value in my shop.

[Steve Ryan]

Looks like a lot of positive reviews from people using the baffle in real world situations. Negative results make the OPs research suspect because it is not a real world test. Testing with the same shavings and such repeatedly will change the composition of the chips and dust being collected. Larger chips will be broken up finer and finer as they get blasted through the collector. How are the chips being metered into the collector? Is the mix uniform or could there be different concetrations being sucked into the line? Is the chip stream a real world chip stream?
Real world research would require accurate testing with the dust and chips coming from a real machine doing real work. Same wood typ to compare with same wood type. Different machines generating different chips and chip loads, and so on. Seems like a lot of wasted effort with all of the positive reviews the baffle has generated.

[Gary Lange]

I can't understand why you are so bent on proving that the Phil Thien separator does not work. What possible motive can you have to damage a mans reputation. If all these people are happy with the way it works for them and you are not then don't use it. However, to go from web site to web site in an effort to prove something works or doesn't work in just unnecessary harassment of and individual who has done nothing wrong and gives away his invention anyway.

[Myk Rian]

I have a friend (a chemist actually) who uses high octane gas because he kept records for years and found it gave him sufficiently better mileage to justify the higher price.
The gasoline companies and the auto companies say it is a waste of money to use any higher octane than the engine is designed for. Yet he has years of experience to the contrary. I am pretty sure he is wrong.

Those last 7 words tells me a lot.
So, what you are telling us is you don't believe ANYTHING, even if someone has years of records for proof.
That tells me you aren't to be given one moment of consideration, no matter what your views are.

Does this forum offer an "ignore this poster" option?