J. Phil Thien's Projects

My second attempt to make a cyclone
Not sure if it's real original, but I haven't seen it done this compact before. It's made for my shop vacuum which actually is a really good vacuum, the only problem with it, is that it is a pain to empty, and I get no warning if it's full. So I wanted to address these problems with a cyclone.
So before I finished the build I couldn't hesitate to try out the cyclone. I'm very impressed with the separation (over 99%), but I seem to have lost quite a bit of suction. Also the cyclone is very loud, maybe because of air leaks?

So here come my questions:
Is there an easy way to measure suction? I've seen mathias wandel on woodgears-ca use silicone hose and water to measure pressure, but I don't understand that method completely...
Also how to make it work with small power tools that reduce the airflow?

I have never built a separator for my shop vac so I am probably the least qualified to help you, but I'll give you my thoughts.  With regards to measuring the suction (static pressure) the easiest way is the method you referenced, i.e. a  u-tube manometer.  If you do an internet search you will find a lot of help on how to do it.  There are also you-tube videos to help.  I could not help you any more than those sources.   I can tell you that in my DC system the separator causes a 35-40% loss in air flow.  I would not be surprised if you are experiencing something similar in suction losses.  Separator losses are a fact of life.

With regard to noise, I suspect your waste drum may be partly or wholly responsible.  It appears to be a plastic storage box, which is fine IF it doesn't deform from the high suction and allow air to leak.  Keep in mind shop vacs are high vacuum, low volume devices, and they can collapse containers that a DC cannot.  I suspect the relatively light walls of the box allow much of the noise from the air turbulance in the separator to escape and it may even add some amplification or vibration of its own.

With regard to small power tools, I'm not sure exactly what kind of problem you are experiencing, but generally a shop vac is well suited for small tools.  However, if you choke off too much of the air flow it will not do a very good job.  Some small tools can be a problem.  For example, pad sanders have shop vac connections, but they still allow dust to escape and become airborne, and to capture that dust you need the high volume of a DC?