fivestring, Until I read a lot of good info from various sources such as the link Gary (chilimau) posted, I had intended to use barrels upstream of the blower to collect "the stuff" but now know that if the system is powerful enough to get the fine dust, not just the chips, shavings, and sawdust, that it will pull the lighter stuff right on through the upstream container.
There are two distinct problems to be solved. 1. collect most of the debris so you don't have to sweep up so much. 2. collect and retain the most carcinogenic material (fine dust) at its source before it gets mixed into the air you are breathing.
I have one of the ceiling filters. It will be better than not having it but it will not protect you while you are generating fine dust.
The ceiling filter cleans the air (with good installation and luck) in an exponential decay manner similar to the idea of "half life" in atomic decay. It may eventually clean the air sufficiently but it takes a long time and doesn't do much for you at the time you are creating the dust. The filter is great to run for a while before doing any painting or varnishing. Stand by, here comes one of my favorite demonstrations...
Put a couple tablespoons of milk in a clear glass and place the glass under the tap running a "medium" stream. Watch the rate of "clearing up" of the mixture after it begins to overflow. Note how long it takes before the mixture is truly clear looking. A fan with a filter (the Delta unit and others) works like that. Even if it removed ALL particles it took in, it would work just like the milk in the glass.
These filters have their use but protecting you from dust inhalation while you are generating the dust, isn't it!
With risk of seeming to be a "Chicken Little" proclaiming the sky to be falling, I'm telling you that your present setup before or after installing a ceiling filter fan (or two or five of them) does not collect the most dangerous part of the spectrum of dust particles in a manner that produces a safe environment while the contamination is being generated.
If there is doubt, check into industrial safety practices, OSHA, etc. Factories are checked for meeting minimum air quallity for protection of the workers whilie we hobby types are typically blissfully ignorant of the "real deal." Typical hobby setups are so much worse than the minimum standards that we often inhale more fine contaminants in minutes than factory woodworkers do all week.
Of course it is easy to give examples of "Old Joe." Old Joe did such and such for xx years and he never had a problem. My mom is in her late 80's and smokes. She doesn't have lung cancer and is in great health for her age THEREFORE smoking is healthy and contributes to longevity. Whether or not walking across the street without looking in either direction for cars is safe, some one may do it for a while and get away with it. If they are killed they never tell anyone so the myth of safety remains unchallenged. //SOAPBOX MODE OFF//
I will be building or buying a cyclone type dust collection unit. As the shop is a conditioned space, at least in the hottest and coldest times, I have an additional problem. If the cyclone output is outside I will pump all the conditioned air out of the shop and waste a lot of electricity and $. I will need a large HEPA type filter on the output which will be ducted back into the shop. LIke you, I want the unit itself, which can be quite noisy, outside away from me.
[img]/forums/images/icons/smile.gif[/img] Pat [img]/forums/images/icons/smile.gif[/img]
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