On Thu, 18 Nov 2004 07:14:59 GMT, Rick Frazier
wrote:

Eric:

Yes, typical cyclone receives the junk from the shop, and has an extractor
on the output. Most cyclones don't really need a filter (bag) on the
outside of the cyclone, because they are extremely efficient about
separating dust and debris from the airstream. However, if you are one to
do a lot of fine sanding, I would think about using something with an
"after filter" just in case, particularly if you live in the city and have
a neighbor within a hundred feet or so... A typical DC will have a
reasonable filter to use as an after filter, and most don't drop the
airflow so much as to make you want to remove them....

Any decent Cyclone will drop most of the debris from the airstream. Even
my home made cyclone (from a 55 gallon drum) will drop just about
everything except for the very finest dust (which could really just go
outside, as I live in the country and don't have any neighbors within a
mile on that side of the workshop) when the cyclone drum is working.
However, if you forget to empty the drum (cabinet in your case) you will
get a lot of dust [DAMHIKT], followed by possible chunks into your DC
bags. Thus, it is still a good idea to run the standard bag filter on
your DC, and to check the drum (cabinet) often to determine when it is
time to empty it.... Just to see what effect it would have, I left the
bags off my DC for about a month (but watched the drum to make sure it was
never over half full) and I had but the very lightest dusting of extremely
fine dust in the shed (about 6x10 feet) the DC lives in. However, I don't
always remember to check the cyclone drum, so I always run with the filter
bags on my DC, just in case. This has saved me a bunch of work with the
shop vac on at least one occasion in the past year...

With the homemade cyclone I have, I can run with the filter bag off of the
DC without any visible dust output until the drum is at least 2/3 full. I
would imagine a commercial cyclone could stand a higher level of debris
before it loses it's effectiveness, however, in the interest of making
sure our environment is protected, I would suggest you continue to use the
standard bags your DC has, AND check the DC bags periodically. Any
significant dust in the DC bags indicates it's way past time to empty the
cyclone drum/cabinet!!!

Good Luck, I'm sure you'll love having a cyclone

Thanks
--Rick

Rick..
I need a cyclone type lid for the DC being shipped to me... any
hints/pic/plans available on what you built?

thanks,
mac