Newbie with 5 gallon bucket separator questions!

[DaddyHeaton]

Hello, I am new to dc.  I decided to build a Thien baffle because it looked easy and it would not break the bank.  I am starting on the woodwork on a remodel, and thought it would help keep the dust down.  I tested it and I'm not sure its performing as well as it should.  I sucked up about a 1/4 full of a 5 gallon bucket and ended up with maybe a little over a cup of fine dust in the filter.

My first question is do I have the elbow placed correctly over the 120 degree Section?
My next question is how far should the center pipe go into the baffle?
My last question is how can I tune it to Perform better?


Thanks for any help that you might be ableto give me!

[DaddyHeaton]

Thanks for all the help

[jdon]

Okay- it looks as though nobody replied to your questions, so I'll give it a shot. However, I'm a newbie myself, and in the process of building my own separator, so do not consider the following any sort of expert advice, rather a reflection of my understanding of posts on this forum.

First, the orientation of your baffle is correct- the "solid" section (180 degrees without a slot) should be right in front of the intake.

Second, for me at least the answer of the height of the center pipe (outlet) is confusing. My interpretation of the original description by Phil is that it should stick down about half the diameter of the pipe from the top. Other posters have place it half the diameter above the bottom (the baffle). For the standard separator, the thickness of the chamber is about the diameter of the outlet pipe, so it's the same distance either way. Once you get into more elaborate designs, where the chamber is a lot taller, as far as I can tell the distance is best at about half the pipe diameter above the baffle. In the picture of your build I can't see the outlet port, but if it's the same diameter as your intake port, say 3", I'd start at about 1-1/2" above the baffle, but make it adjustable to start with. That way, you can adjust for optimal placement. Higher will give better airflow (suction), but allow greater bypass (more dust will go on to your DC or vac. Lower will improve separation, but if too low airflow will suffer.

Third, things you might do to improve performance:
1) chamfer (bevel) the bottom of your slot. The top of the baffle should be flat, but a sharper edge  will help separation.
2) Anything contributing to airflow turbulence will decrease separation performance. Ideally the airflow coming into the separator should be tangent to the wall, so it has a smooth circular path. I can't tell whether your elbow inlet is pointed outward a bit- if so, the air will tend to bounce off the wall.
3) If you can make the baffle supports thinner, you will get less turbulence. Threaded rod or wooden dowels should be plenty strong to support the baffle; a thinner baffle (say 1/4" Masonite or plywood) would be lighter, and also have a thinner edge at the slot. Also, from designs I've seen I recall that the supports are closer to the wall- yours seem pretty close to the center, which will interfere with smooth airflow into the outlet port.
4) Finally, the basic Thien design seems amazingly robust (forgiving): you're going to get very good dust separation with just about any build that approximates Phil's original design. A lot of the discussion seems to aimed at fine tuning modifications and optimizing, but with diminishing returns.
Just my .02  :)

[phil (admin)]

Your baffle is not oriented correctly, the inlet should be about 1/3rd onto the larger radius.  The location where you have yours will likely siphon material from the bottom of the bucket.

The outlet should stick at least 1/2 the D into the separator, so for 2" pipe that would be 1".  Some people find success having it extend further, there seems to be all upside to doing so.

Your supports for the baffle may be too large in comparison to the volume of your separator, they may interfere with rotational airflow.

When you test, make certain you aren't just pushing the hose into a large pile of debris, as doing so will starve the separator for airflow, greatly reducing separation.