On Sun, 24 Aug 2003 06:51:01 GMT,
nospam firstname.lastname@example.org (coloradotrout) Crawled out of
the shop and said. . .:
agreed, and also agreed to your follow up.
personably, i am not really all that worried about the finer dust,
most would argue its the smallest particles that do the most harm, but
i am of the opinion that i get more nasty crap from a southbound
greyhound than i get in my shop.
when i woodwork, i am there to have fun, create something from wood,
and to leave most of my troubles on the outside of my shop door.
I believe the flaw in your argument arises from the fact that for most
people their dust Masks, while offering some protection, do not work as
well as they think they do. And most health concerns are caused by the
A dust mask (like those worn by Drs. in surgery) are worn to protect
the patient from the Dr's spital and nasal secretion and not to protect
the Dr. These are often the same type as we WWs ware. The seal between
the mask and your face is not adequate to stop small particles from
being inhaled when you breath. Even with a proper (and fitted)
respirator the seal is only effective if you are clean shaven (for some
guys every four hours). As your face sweats and breathing is impaired
somewhat from wearing it, people tend to wear them less and less. That
is why every attempt should be made to keep the dust from becoming
airborne in the first place. Now, if you are going to go with a battery
operated powered respirator then that can be a different story. Cheers,
I don't like wearing the mask either. I have a 3M flavor that has 2
elastic straps. A few years back it was suppose to be one of the
better disposable ones for wood dust. It's not a cartridge unit,
though I have one of those, but it's too heavy and annoying (have used
it for spraying).
I don't see how any of the bag units can be perfect. Even if they say
0.3 micron, is that realistic? I'd guess it's more like saying the
bag (in the ideal situation) can get 0.3 microns. In reality, though,
it's probably no wheres close. I'd like to see published specs on the
canister units. And I just can't fork out 800+ for a stationary
Getting a 5, 3, or 0.3 micron bags these days is pretty inexpensive,
so that's where I'm headed. But if the small stuff is the worst, I'm
not very confident any of the current solutions are as effective as
one might initially believe. Capturing the dust at the source would
seem nearly impossible for most tools, e.g. contractors TS, SCMS.
Jointers, planers, and DPs would seen to produce mostly shavings, that
would be of less concern.
For the air filter unit, I was thinking of putting in 2-3 Filtrete
filters (used furnace , then vacuumed).The filters would seem to be
the ONLY way to capture airborne dust that has eluded the collector.
I guess an interesting question.. is how much of woodworking dust is <
How much is <2microns? That is a good question or at least one that I
researched a bit when I use to work in the hygiene field. As you state,
planers, jointers and DPs create very few small particles. Sanders create
a lot, with a TS somewhere in the middle. This is one consideration
however you must also consider your duration of exposure and the type of
dust you are exposed to.
As I have spent more and more time in the shop over the last few years I
have come to realize what an academic exercise this (exposure to small
pcles) is. For a shop like mine where our tasks change everyday there are
so many variables.
What I have noticed is that my filter ( IIRC 1 micron) in my cyclone
starts to clog quite quickly (within an hour) when I use it for my drum
sander but will run with little impedance for weeks if I run only the
So now when I use a hand sander, not hooked to the cyclone, I wear a
proper respirator if its a long job and a dust mask for the short jobs. JG
Steve is a big proponent of felt bags. With multiple paths provided by the
felt structure, the air pressure is low in any given path, allowing
particles to precipitate or "catch" in the fibers. With higher
airflow/lower backpressure in the bag, even the non-bag components don't
leak as much - lower airflow - so it's a win/win.
That said, the principle behind felting is to take a bunch of fibers and
intertwine/compact them. This is also done inside any bag by accumulation
of sawdust "cake" which first filters finely, then ultimately clogs. You
can also reach this state in felt bags, so keep an eye on them. They are,
after all, fibers. If you have a bag which is not passing visible dust,
and I mean visible in a concentrated light beam, you're fine. Until you
reach that stage, wear a mask. When you clean a conventional bag, don't
shake the cake, and you can return to that fine filtration stage that much
Now, as proponents of felt point out, this method does produce higher
backpressure, and therefore is less efficient at pickup, though efficient at
filtering. My little 3/4 horse keeps up with the planer, pulls nails and
such off the floor, so I guess it's enough in both capacity and vacuum for
Final point. You are equipped with an exceptionally great system for
accumulating and rejecting particulate matter in your nasopharynx and
trachea - mucous and cilia. If you can't color a tissue, you're doing
fine, no matter what the naysayers try to make you believe.
this is the wrong thinking. the dust cake does not shake off very well. too much
cake and you have back pressure and the back pressure forces fine dust out of
the bag. the bag will filter the best when it impeades the airflow the least.
this is why a bigger bag is always better. the more often the bag is shaken the
the commercial bag houses have auto shakers to keep the bags clean. Once I
found out about this I got better use and airflow from my big felt bag.
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Custom made wooden planes at reasonable prices
If it were true, I would believe you, Steve. But, as it is not, I'll go
with what I said.
The big people use felt bags, as you said, and as I said or implied, felt
bags need to be shaken or cleaned lest they fill from inside out. Non-felt
bags operate on the pure filtration principle, and are therefore more
efficient at filtering when the gap size between medium is smaller..
I'm kinda following..
So any suggestions for bags? The Grizzly 0.3 micron? or 3.0 micron?
Why would ANYONE buy the 3.0 micron for $20 when the 0.3 micron is the
The envelope style? Mmmm.. how about I put a solid plastic bag (or
rig a canister to the bottom side, and then add TWO bags to the top
side -- even if it rubs up agains the ceiling?
Do the seperator lids really make a big difference? Logically.. is
seems like they would --get the chunks out -- spare the blade -- and
facilitate mulching the garden!!!
One could always stitch two top bags together to form a Y
to recoup the airflow. A slim piece of trim wood over the
holder would keep their arms up. Not a problem.
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might be talking 2 things here
the seperator lid would just be one of those trash can lids piped in
ahead of the DC
if i put a plastic bag or canister as my bottom bag of the DC, then
I'd have to add surface area somehow.. presumably. I thought i could
do that by sewing 2 bags tog. for the top bag. Probably would hit the
ceiling, but w/ those envelope style bags, seems like it would be
pretty easy to do.
how big a "chunk" can make it through the fan blade? seems like a
1x1x1 could do a lot of damage.
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