# Thien Baffle...how tall to make one?



## Starfury (Jul 1, 2015)

I'm doing an upgrade from the shop vac/dust deputy set up I'm using…the shop vac is getting a bit tired and it's really noisy. I'm going to get a HF dust collector and connect it to a thien baffle on top of my collection barrel. My main issue…how tall do the sides need to be? I've seen them 6" tall up to around 10" but nobody has a fixed "make it this way for best results" guide. My piece of lexan is 12" tall. I can cut it down if needed…but would it hurt to have the baffle that high? I"m also not 100% sure where the intake should be but near the top seems to be the best place.

Basically…I want to build this once and have it work right. Re-building the same item over and over is a waste of time/material/money. I want to minimize the cleanup from projects and have a cleaner work environment. A future project will be a downdraft table of some kind for when I'm sanding smaller pieces.


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## crank49 (Apr 7, 2010)

A Thein Baffle is a cheap cyclone.
The baffle and the cyclone both work by accelerating dust and air in a circular direction so the larger particles are stripped from the air flow by centrifugal force. The slot of the Thein baffle and the bottom of the cyclone that expands into the dust bin at the bottom serve to allow the dust to escape in one direction and the air to continue in the other direction, back up to the duct leading to the fan inlet.

Why am I explaining this? Because the action of accellerating the flow requires a good amount of pressure. Pressure in a dust collector costs horsepower. A lot of it. If you don't add horsepower in the form of a bigger motor, the system will balance itself by reducing the air flow.

Basically, the HF dust collector is a decent machine as it comes from the factory. I've used one for almost 10 years. It does need to capture fine dust better. The best way to do this is with the replacement of the 30 micron bag with a cartridge filter. This is by far the best improvement you can do.

The secondary best thing you can do is to put an expansion chamber between the dust source and the fan inlet. This can simply be a trash can with an inlet and an outlet pipe in its lid. This chamber will capture most of the big dust and chips without dragging the system pressure down like a cyclone or Thein baffle will.


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