Given that a shop vac can deliver much more suction than a dust collector (albeit while moving less air) the added static pressure of a trashcan separator should have minimial impact on the airflow.
Chris
Like a ton less air! A typical shop vac will move a tad over 100 CFM. A HF dust collector is rated at 1200 CFM, but my bet is they are bragging a bit high. Even so, about 10 times the air flow. You need air flow to move chips, static pressure, (suction), don't do squat for moving chips. Moving dust you have pretty much zero static pressure any way, maybe 4-5 inches of water column. Skip the trash can separator and try the shop vac direct, it still won't do a very good job. A few years back I tried doing this with two shop vacs hooked up, and it still didn't work. My el-cheapo HF dust collector bet it by a mile. Greg
Probably not. The key is how you define suction.
Most people think of suction as either air speed or how much pull the end of the hose has against your hand. But these are only components of what really defines how much dust is collected: VOLUME OF AIR MOVED. According to,
Bill Pentz Dust Collection site is a good primer:
So a shopvac moving 100cfm through a 4" hose gives much more suction than a DC moving 800cfm. What exactly is your definition of suction?!?!
A shopvac will do better when attached to a ROS than a DC will, but that is only because the openings are so small that the DC is starved for air. A planer is an example of where exactly the opposite is true; the DC is 5 or
10 times better.And if you did put a separator on the shopvac you had better seal that sucker perfectly, as any leak will pretty much kill it. A DC doesn't much care about small leaks.
How many water column inches it can raise.
Yes. I was simply objecting to your statement that adding a separator to a shopvac will cut the airflow.
Chris
I'm defining suction as vacuum pressure, or water column inches, or something similar.
Of course the shopvac won't move as much air as a dust collector, it's a totally different design. However, because of that difference in design adding a separator to a shopvac will have minimal impact on the volume of air moved because it can easily overcome the static pressure of the collector.
Conversely, a dust collector moves a lot of air but is sensitive to static pressure increases. Thus adding a cyclone or trashcan separator can have a large impact on the airflow (depending on the fan curve, of course).
Chris
It might be a difficult concept, but water column inches is pretty much irrelevant when you have free air flow, like on a planer. I am sure it is all explained somewhere.
Tue, Oct 2, 2007, 12:34pm (EDT-3) snipped-for-privacy@yahoo.com (Dave) doth sayeth: I have a typical Shop Vac I use in my garage which works great for small projects. The only thing I don't like about it is when I use it with my planer (as you want to do) I need to empty it every few minutes.
You could adapt it to dump into a large garbage can. That'd help some.
JOAT "I'm an Igor, thur. We don't athk quethtionth." "Really? Why not?" "I don't know, thur. I didn't athk."
You can suck the same water column through a plastic coffee stirrer as you can a large straw. But you would never drink through the stirrer because you can't pull drink through it fast enough to be useful.
Same thing with a dust collector. No matter the pressure at the motor/impeller side, through a 2-1/2" hose you simply can't pull enough air (entrained with dust). You need at least 4" duct, but preferably 5-6" with a motor/fan sized accordingly. The magic number is 800-1000 CFM. Imagine a 10'W x 10'D x 10'H room. Per minute.
The magic number
I never thought of it that way before; interesting. Of course, that is only
15cfs.digitect wrote in news: snipped-for-privacy@SPAMdancingpaper.com:
*snip*
Wow, that sucks.
Puckdropper
have you thought about the Mini CV06 cyclone.
That worked for me. I put between my shopvac and the tools. You can put any size containet you like on it. It is in the background on this pic.
probably true, but not difficult to do as you can see from my one.
The reason for the lashup is that many materials are hard to come by in tth LOS
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