J. Phil Thien's Projects

Quote from: Rudy81 on August 28, 2013, 04:32:23 PM
Bulldog8, thank you. I see what you did now.  How did you adhere the lexan or acrylic to the wood structure?

It's mechanically held in place with the grooves and stopped grooves and then sealed where the plastic meets wood with clear silicon on the original and white silicon on the "tall" version. I sealed on the outside of chamber as to not put anything on the inside that could create turbulence.

I didn't join the ends together. The groove in the top starts at the inlet and stops at the end of the 240 degrees. The only portion of the baffle that was grooved is the 120 degree area.

I don't have many pictures of my last build with the tall chamber, but here is a shot of my first separator to show what I mean. My current tall chamber separator is similar, the top groove starts at the inlet and goes all the way around stopping just short of where the inlet starts. The bottom plate is grooved from the inlet through the 120 degree solid area. The bottom of the wall is then free through the 240 degree area, with a small stop groove right where the inlet is located. The outer wall is sized to press fit in and has been sealed to the wood surfaces with clear silicon.

I made my first separator with a 3/4" baffle and chamfered the edges; it worked ok. Later I made a 5 gallon separator for use with a shopvac and used 1/4" hardboard. Hard to tell which was better as one was with a DC and ducts the second was a shopvac set up.

This past winter, I rebuilt my main DC separator and used a thin metal plate. It seems to separate out fines better than the original with the 3/4" baffle, but I also changed the inlet and chamber height so it's hard to say which of the changes gave the most improvement. Overall, the separation of fines is now very good.

I am considering using the Jet separator and building a baffle for it the inlet seems to be only 5" (I haven't opened the box yet). My assumption is that the 5" inlet is a compromise when planning on using 6" pipe.

I'm running a 6" main duct to the tophat and then 5" from the tophat to the blower. Works, but I don't know if I took a hit or not. My DC is a Griz 1029 2 hp that originally had a Y the had two 4" branch's so I didn't think that the 6 to 5 would hurt too bad on the outlet, but I wouldn't want to choke the inlet.

First question is, am I better off building a custom separator with a 6" inlet, vs the Jet 5" separator inlet?

Pretty easy to build a custom tophat and your own inlet, that lets you go from round to rectangle.

Second, if I build a separator, will I benefit from making its depth 12" or something deeper than the inlet tube?

I did both and guesstimate that I get better fine separation with the tall chamber

Third, in a DIY separator scenario, will I benefit from angling the inlet tube slightly down toward the baffle?

On my build it sure seems to help, I get a definite downward swirl.

Fourth, any definitive recommendation on whether the  vertical pipe going to the DC should be flush with the top of the separator, or should it enter deeper into the chamber?

If you build a chamber the thickness of your inlet, say 6" and have a 5" outlet pipe, the outlet pipe should protrude 1/2 of that diameter or 2 1/2" down into the chamber. If you make an artificially deep chamber add the extra depth to the 1/2 diameter distance.

That sounds really good. I agree that you should clean out your filters and then give it a real world test of a day or two of woodworking. After that blow the filter down and see how many fines you get. If your happy with the amount of fines that made it to the filter you are all set. Nothing will keep all the fines out, so once you get the performance that led you to building the separator in the first place you are set.

Steve

I think the problem you are having is that most people don't index the drop slot from the leading edge. Well at least I didn't. I worked from where I wanted the slot to stop and went 240 degrees back around the circle. Typically most people will stop the drop slot right at or just prior to the edge of the inlet. Because inlet widths verify in size and shape planning the drop slot in relation to where you want it to stop, makes things easier.

Here is a drawing from Galerdude that shows his layout and the relationship to where the slot stops that I am talking about.

You have a 6" inlet and what looks like about 2" above and below the inlet, about a 10" tall chamber. Normally, the outlet pipe would be 1/2 d (3") down from the top of the top hat. Yours looks deeper, which is a good thing with the tall chamber.

So if you raised your inlet port as high as possible (about 1/2") down from the top, incoming air and dust would have to move downward to the exit pipe. This downward movement in conjunction with the circular motion of the incoming air stream gets the dust moving in the desired direction. (to the collection barrel)

An inlet pipe that transitions from round to rectangular as it enters the top hat causes the velocity to drop somewhat and keeps the air stream against the chamber wall.

Here are pictures of my first and second top hat. Both have a 6" inlet pipe. The chamber height of the first was just barely enough to fit the 6" inlet, the second has a tall chamber with a deep outlet. I've also bent the round inlet pipe into a rectangle shape. Others have done a better job in the round to rectangle transition. If I ever rebuild it, I'll make the rectangle even taller and thinner. I had good separation with the first one, but was intrigued with reports of success with fines with the "tall chamber" variant. The tall chamber works well with my tools. Bother my planer and jointer have Byrd heads so I don't get large chips of anything. Before I had the Byrd head on the planer, I had fairly large shavings with some woods and suspect that the tall chamber might not have handled them as well as it does the finer dust.

Separating fines is the reason I built my first Thien baffle. I was plagued with clogged bags when running a drum sander.

It looks like your drop slot is more than 240 degrees. That may allow too must air to swirl below the baffle not letting it settle out.

The thick baffle definitely doesn't help. You could cut your thick baffle back even further to use as a support and then add a thinner baffle plate to decrease the baffle thickness and decrease the size of the drop slot.

Raising your inlet pipe and/or going from round to rectangular will also help.

Quote from: jdon on August 12, 2013, 10:10:22 AM
I'm curious about Bulldog8's design- did you keep the same orientation of the baffle slot and the inlet- that is, did you leave the 120 degree solid section in front of the inlet?

My impression is that the orientation of the slot is important, at least when the inlet is just above the baffle.

In Bulldog8's video, it looks like the air path takes about two full 360's above the baffle. I can't tell whether: a) Bulldog8 carefully designed the geometry (inlet angle, height, etc.) to get good separation; b) he was just real lucky that the slot just happened to line up well with airflow by the time it hit the baffle; or c) maybe the orientation of the slot isn't all that important, at least with a tall separation chamber.

Still trying to sort out the complexities :P

I left the 120 degree solid section right in front of the inlet as you normally would. Everything else was a SWAG. I made the rectangular section the width of some scrap wood in the shop. (scraps and clamps to do the forming) If I was ever to build it again, I'd increase the height and decrease the width, in an effort to keep the air stream close to the wall.

I didn't really have a plan as to how much I would increase the chamber height other than to double what I had before. So I went from 6" round inlet to a rectangular inlet. Previously it seemed like the dust dropped below the slot just before the end of the 240 degree portion. (in fact I chamfered the end of the slot in an attempt to help my 3/4" baffle drop debris below the plate instead of having to go around again.

I found that I usually get a very nice two times around swirl before the dust goes below the baffle. Different woods and different machines separate a little differently, but for the most part I get a nice thin stream twice around the chamber.

I was referring to the distance from the top to the baffle. In this build, I held the inlet to the very top of the chamber and then moved the drop slot/baffle a lot lower than I needed to. Previously, I had the baffle right at the bottom of the inlet pipe.

In this configuration, the outlet, or suction pipe is pulling the dust downward with seems to increase the cyclonic action. The dust travels twice around the chamber in a nice swirl before going through the drop slot.




Here is a video of it in action.

http://www.youtube.com/watch?v=RNl6sMVSVss&feature=em-upload_owner#action=share

I just finished rebuilding my baffle and incorporated a round to rectangular inlet, tall chamber and a thin baffle. My original top hat, had a 3/4" thick baffle that I chamfered to thin the baffle.

In the new version, I narrowed the drop slot to 7/8". (Planer and jointer have Byrd heads so I get small chips instead of shavings)

The baffle plate is cut from 20 gauge steel and is supported by a smaller baffle under the steel baffle to eliminate the need for a support rod. (sandwich baffle idea like GAlawyer's)

Originally my chamber height was 6 1/2" with a 6" round inlet. After reading about the benefits of increasing chamber height, I now have a 14" chamber and get a really nice cyclonic action. I haven't attempted any empirical testing to measure CFM changes or level of separation. It was good with the old top hat and fine separation seems even better now. (based upon the drum sander)

Will get a couple of pictures posted this weekend.

Steve

Do you have the specifications for the Karcher vac? That would help to answer the question. I assume that it is similar to our "ShopVac" which means it wouldn't be a good choice for some of the tools you have listed. (Primarily the planer)

Smaller vac's tend to have a higher static pressure, (more suction) than a traditional dust collector, but the trade off is that they move less air. That is ok and even beneficial for hand held tools. Many people will use a ShopVac to collect from routers and hand sanders and a dust collector for the table saw and planer.

I really don't think that you are going to move enough CFM with a squirrel cage blower to effectively capture the dust. They seem to work fine in shop made air cleaners, but not for dust collection. I use a 5 gallon separator with a shop vac for sanding/routing/hand held power tools. The separator is connected to a QSP Shopvac; don't know if they still make them. But it's quieter than my Porter Cable ROS and 1/4 sheet sander.




Steve

What are you using for a blower? When I think of a scroll saw and a five gallon bucket, I think of a Shopvac. I don't think you will be happy with a Shopvac on a 4" duct.

Steve

It sounds like the OP understands that running without a filter will increase the amps his motor is pulling.

Will the Thien Baffle provide enough resistance to bring your amp draw down to an acceptable level even though you are not running a filter? I has for many, but I feel that there are too many variables to give an answer. The size of your duct, leaks, 90's, number of blast gates open, will all change the amp draw. An amp meter is a handy thing to have; I'd suggest getting a clamp on meter and test "your" set up under real working conditions.