I have a dust mask but I wonder if it is worth wearing when working on pine wood. I do wear it when working a piece of oak or beech.
Would you consider cutting some wood species without a mask safe? Do you use a mask with every wood species? How long does dangerous dust stay in the air?
Also, is a mask still necessary when using a central dust collector?
I've a dust mask but I wonder if it worth wearing it when working on pine wood. I do wear it when working a piece oak or beech.
First off, let's be clear: a disposable paper dust mask may be slightly better than nothing, but even a fancy $5 disposable P100 dust mask with a breathing valve will not perform as well as a properly-fitted respirator with replaceable P100 filters. If you have a beard, you should consider a positive-pressure respirator since a normal respirator may not be able to make a good seal with your skin.
Some woods are more toxic than others, and some people are more sensitive than others to certain types of wood. The Wood Database contains toxicity information for many types of wood, including possible symptoms.
Would you consider cutting some wood species wood without mask safe ? Do you use mask with every wood species ? how long dangerous dust stay in the air ?
I consider cutting any wood without a respirator unsafe, regardless of species. The length of time dust remains in the air will vary, but I've seen at least one magazine article recommend continuing to wear a respirator for at least 30 minutes after you stop producing sawdust in that room, assuming the air is not disturbed by a fan or air handling system.
Also, is mask still necessary when using a central dust collector ?
Would you rather have your lungs or a respirator filter the particles out of the air?
If you want to err on the side of safety, you need a properly-fitted respirator with P100 filter cartridges. Few, if any, dust collectors are capable of capturing 100% of the dust at every tool (it also depends on the tool's design), and very few dust collectors provide filtration adequate for removing sub-micron particles. Most inexpensive consumer-grade dust collectors only filter down to 1, 5, or even 30 microns. A dust collector outfitted with this type of filter will simply recirculate the sub-micron particles through the air, allowing them to increase in concentration as you continue to work.
If exhausting your dust collector to the outdoors is a practical option, you may want to consider that rather than spending a lot of money on HEPA-rated dust collector filters. The obvious drawback is that you will also exhaust all of your warm air in the winter and all your cool air in the summer. Also be certain to include an air inlet if exhausting outside. Otherwise, your dust collector won't work as effectively; and worse, negative pressure inside your shop can cause the combustion gases from a water heater or furnace sharing the same space to be pulled back into the space--for example, if your shop is inside your basement.
@bowlturner and @rob gave some excellent responses and I'll add a couple of thoughts:
Remember there's a big difference between collecting chips and collecting dust. "Dust collectors" are often good at collecting chips, but allow the fine dust to escape. What that means is that you can have a visibly dust-free shop and still have major dust problems. You might want to check out Bill Pentz's website for more details on how much cfm is required to collect the fine dust particles at the source.
Repeated exposure to airborn dust can, over time, have detrimental effects. So, for example, if walnut doesn't seem to bother you now, it may decades down the road. (I've heard stories of woodworkers who have had to retire early because they developed an allergic reaction).
It's probably better to be safe than sorry. (This is coming from someone who rarely uses a dust mask...ahhhh the feeling of invincibility among the youth).
I tend to choose whether to use a mask, not based on which species I'm cutting, but which operations I'm performing. Jointing and planing--no dust mask. Table saw/bandsaw/sanding--definitely wear a mask.
For my shop, I have a three-stage strategy for dust collection:
Collect as much as possible from the source using a dust collector. For table saws and routers, that means both from beneath and from above (I'm personally still working on this).
Have a filter running whenever I'm in the shop. I just attached a furnace filter to a fan, then placed that on the same switch as the light--anytime I turn on the lights, I'm turning on the filter.
Leaf blower...seriously. Every night when I finish working, I use a leaf-blower to excavate the dust from my shop. Obviously, this will initially stir up dust (so wear a mask!), but I'm hoping that over time, it reduces the accumulation of dust that can be stirred up.
I hope that helps!
Would you consider cutting some wood species wood without mask safe ?
I do all the time. However, I also have a dust collection system and 2 different kinds of face masks that I also use. Exposure makes a difference. Some people are susceptible to different things vs. others.
Do you use mask with every wood species ?
For me two things make a difference to whether I wear a mask. The first is how much exposure am I dealing with. hours in a sawdust filled room with suspended particles? definitely wear a mask, sanding? working at the lathe? Yes and yes. One cut with a miter? no, hand saws? no likely.
How long dangerous dust stay in the air ?
The dust can stay in the air for quite a while, espeically the smallest and most dangerous particles. Some dust collectors don't even filter out the smallest particles and actually push them back into the air, these are bad because they are kind of like asbestos in that they get into the aveoli in the lungs and can damage them. Some species like Walnut have extra 'natural' chemicals that add to the issues. There is always the possibility of allergic reactions as well.
Also, is mask still necessary when using a central dust collector ?
A good one will filter to 1 micron, but many only filter to 5 microns. these are the most important particles to remove. overhead filters are really a good thing to have as well. How much stuff are you cutting and putting in the air? a couple cuts an hour? not to bad, lots of cutting? If you are sneezing or have black/brown boogers definitely be wearing a mask.
But ultimately, it's your health and your lungs are important, if you question it, tend to fall on the side of safety and wear a mask.
For reference regarding toxicity, http://www.wood-database.com/wood-articles/wood-allergies-and-toxicity/ is a pretty good resource, but as with any allergy, some people are more allergic than others. Bear in mind it's not just toxic particles that are dangerous; for example, bakers are known to have health complications from inhaling flour.
In general, if I'm doing anything more than cutting a couple boards to size, I wear a mask. Even if it's not likely to cause health problems: I don't like having sawdust boogers ;)
