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I’m a little confused as to what the width of the slot is. I saw a video where the guy said he read it was supposed to be 1 ¼”, but yours looks wider. Does it matter?
You can always go back to the fellow who started this, Phil Thien.

http://www.jpthien.com/cy.htm

"The bottom view of the baffle. The baffle is cut such that its large diameter is the same as the inner diameter of the can measured at approx. 3" down from the rim. 120-degrees of the baffle is left at this larger diameter, while 240-degrees of the baffle is reduced in diameter by 2.25" (forming a 1.125" "drop slot"

My slot may have been 1 1/4 - 1 1/2in. I recall I was constrained by the piece of plywood I was using. It was not big enough to get to the slot size Phil Thien used.

I think if the slot is too large, more of the debris will escape up into the cannister. If the slot is too small, it will get choked and not allow the debris to fall into the bottom bag.
 

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Thanks Dave,
I had the same problem with the Plywood size. I have a piece of ½” x16x24 and thought about making the slot bigger, but I decided to wait until the sun comes up to find another piece in my wood shed. I may also have to wait until it gets a little warmer to cut a piece outside since I don’t have any dust collection at the moment.

I’ve been thinking about the support for the center of the slot and I think I’m going the use a steel rod all the way through the housing keep the slot as unobstructed as I can.

Most of the Thien separators I’ve looked at so far have the outlet protruding a little into the cyclone cavity and I know this has a cone, but I was thinking of using some sheet metal around the inside cone to drop down a little just to prevent any dust from getting up on the cone.



Anyway I don't know if it will work but I have a piece of 10" sheet metal duct that I'm going to cut
 

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I’ve been thinking about the support for the center of the slot and I think I’m going the use a steel rod all the way through the housing keep the slot as unobstructed as I can.
The baffle needs to be place below the inlet. I think the collar you show in the sketch would block all airflow to the slot causing all the debris to go upward.

You do not want to impede the airflow under the cone and between the cone and the baffle.

I am only using 1/4in thick plywood, and have this attached at only 3 locations. You mention using 1/2in plywood, even stiffer. It will only need a few points of attachment to the outside of the DC middle section. I glued on scrap blocks to span the slot gap, then screw in from the outside. Very simple.
 

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I just feel that the cone is like a scoop catching the saw dust as its flying around and just want an edge to stop it from scooping. As it turned out the 10” duct I thought I had was actually 8”, so I’m going to have to wait on that Idea.

We had a fruit cake from Costco on the counter that looked like about the right size so I took the plastic cover off and stuck it into the hole. It was about a 1/32 too small but close enough to tape on. I may cut 2” off the top and give it a try to see if it holds up. It has an interesting shape with spiraling ridges turning in a direction that might force the dust downward toward the slot. My only concern is that it may make the opening a little small because its bowl shaped.



I also have a bucket with straight side that I could easily cut 2” down from the ridge around the handle and shove it in the cone hole.



Anyway I was going to use 3/8 plywood but found a ½” piece of MDF and really didn’t want to waste my plywood. The ¼” steel rod is from a cable reel and I’m just running it all the way through an also use two screws on the sides to keep it from tilting. I’m just waiting for the glue to dry now.

 

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You just need the baffle, no cone or bucket in the hole, which would block the airflow to the upper cannister.

The air rotates at high speed in the middle section of the collector. The baffle keeps the heavier particles in the lower bag by preventing a swirling action in the lower bag.

If the lower bag is plastic, like my dust collector, all of the air needs to flow out of the top through the cannister. The air has to flow through the "funnel" in the middle. If you block the funnel then you will not get any airflow through the collector.
 

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You just need the baffle, no cone or bucket in the hole, which would block the airflow to the upper cannister.

The air rotates at high speed in the middle section of the collector. The baffle keeps the heavier particles in the lower bag by preventing a swirling action in the lower bag.

If the lower bag is plastic, like my dust collector, all of the air needs to flow out of the top through the cannister. The air has to flow through the "funnel" in the middle. If you block the funnel then you will not get any airflow through the collector.
Oh No You don't understand, I'm cutting the bottom of the bucket completely off and it was only going to be a ring about 2" in inside the hole. Nothing is going to be closed off, its only a ring around the edge.

Well actually I just measured the depth with the baffle installed and I may only be able to have a 1" ring around the edge because its only 3" from the bottom of the cone to the top of the baffle. I'm not sure that will be worth it.
 

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Thanks for the clarification. I am not sure if such a modification would help or hinder.

I would be very interested in a with and without such a modification comparison of performance at the tool port and at the machine, although I am not expecting you to spend the time. More than a bit of a hassle.
 

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Well I was going to try operating it outside without the filter bag and see if I can see a difference, but the MDF baffle split in half and I’m going to have to make another one out of plywood or try to glue the MDF back together. I spent about as much time as I can today, but maybe I’ll try again after dinner.
 

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You seem to have more than your fair share of bad luck.

Sorry to hear about the MDF breaking. I appreciate the frustration of the time you spent on it. You may be able to salvage by gluing a piece of plywood across the break. I do not expect glue on the break without reinforcement would help.

Running the unit without the bottom bag should work, especially if you are trying not to use the top cannister. Without the bottom bag there will be no air pressure to push air into the cannister. You should feel more suction at the tool port though.
 

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This isn’t the first time I’ve had trouble with this MDF. Its part of a large sheet I bought years ago and I forgot about it because it’s been in the storage shed for a long time. It looks great and then it splits like a stack of newspapers. I should have tossed it when it first happened.
 

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Sawdust Creator
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Discussion Starter · #33 ·
Sleeper said:
Well I was going to try operating it outside without the filter bag and see if I can see a difference, but the MDF baffle split in half and I’m going to have to make another one out of plywood or try to glue the MDF back together. I spent about as much time as I can today, but maybe I’ll try again after dinner.
As the back pressure would be different with the top bag off, I don't believe that would be an effective method of testing.
 

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As the back pressure would be different with the top bag off, I don't believe that would be an effective method of testing.
Well maybe if sawdust was flying all over the place, but if it all goes down the sides through the slots then I’d say it was a pretty good test :smile:
 

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Not necessarily....with no top bag the air will achieve faster velocity in the separator, which may help it drop out faster.
I disagree, what I'm saying is IF the the saw dust DOES go down the slot without the bag, then it can only be better with the bag.

If it DOES NOT work without the bag, then it proves nothing.

The Wynn filter is supposed to have no or minimum back pressure
 

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Discussion Starter · #37 ·
Fair enough........we can agree to disagree.....What i'm saying is that with a top bag or filter on it......your air velocity will slow down some, thus affecting the results. But the only way to really prove it is to either run some real world tests.....or a simulation, of which I no longer have access to any software that will run that......so we're stuck with tests and results......


EITHER way.....a baffle will be better than no baffle
 

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LOL. You just aren’t seeing outside the box. You don’t need scientific figures to know if something works or not. So if water flows down the drain and you don’t have calculations on how fast or how much, does that mean it doesn’t work? :laughing:

The test I‘m interested in is to see if there is a difference between having a ring around the edge to prevent the funnel from skimming or not. I am NOT conducting a test to see if the Thein baffle is working or not because I already have conformation for that. :yes:

All I care about is that most of the saw dust is going down the slot into the bag and not coming out of the top into the filter, which I should be able to see.

Also if I feed it 5 gal of saw dust and I have 5 gal of saw dust in the bag without the filter then I’d say that was working. And if I only have half of what I put in then it’s definitely a fail and it might have to be farther tested with a filter to see if back pressure has much of a role.

The only thing I will not know is how much very fine 5 micron dust is coming out, but after seeing all that fine dust going up in the air yesterday with my own eyes, I think I'll be able to make a pretty good judgement call.:smile:

Here is a test without back pressure at all and in fact it is a negative pressure. Not scientific but it is pretty easy to see if it’s in the ball park. This particular system isn’t exactly what I’d use for an expensive Wynn filter because there was some loss and hopefully it was due to being sucked out instead of blown out.

I am not recommending this, but only using it as a demonstration of a test.

Anyway I’m growing tired of explaining this, if you can’t understand what I’m trying to say and then I just don’t know what else to say.
 

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Discussion Starter · #39 ·
I understand what your saying, and I was also debating the effectiveness of the 2 inch ring you were talking about installing. Anyhow....glad it's working for you.
 

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I decided to just glue the MDF back together and replace the MDF blocks with pine since there really should not be a lot of pressure on it. Only this time I’m not relying on glue alone to hold the MDF to the blocks and used wood screws through to the pine. The photo below shows the support rod that I ran through to keep the gap up. the rod is only 3/16” thick so there should not be any accumulation of dust on it



It’s too dark right now to do any testing so I’ll wait until tomorrow early afternoon. I’m thinking about videotaping the ring test without the filter bag and hoping the camera doesn’t get covered in saw dust. :laughing:

Oops I forgot to take the clamps off before taking the photo. :icon_redface:
 
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