Odie,
I use a pre-filter on my Jet and it really helps save the filters that are part of the unit. I tape a 12X24 furnace filter on the front of mine and it really helps pick up the majority of the dust that is in the air. The smaller size particles pass thru and then are captured by the other two filters. Depending on how much sanding I do, I replace the pre-filter every two to four weeks. Just a thought.
If I didn't have one and lived in the area, I would jump on it.
Steve
Remember that shop air filters remove particles suspended in the air of the shop - the same thing that your lungs do without costing you for the electricity used. If you are generating enough dust to suspend it in your shop's air, you have a situation where efficient personal protection is absolutely necessary. I have a JDS 750 air filter that uses a 1 micron bag filter; I swapped-out the replaceable filter with a washable electrostatic filter which protects the bag filter, and also use an HVAC-style replaceable filter as a pre-filter (as has been described) to protect the electrostatic filter and to remove the largest particles first. I only use this air filter when I am not in the shop - if there is that much dust in the shop air to need a filter, I get out and let the filter do its job without any help from my lungs!
Some people have described these filters as "shop dust filters" which help keep the shop clean from dust settling out of the air, and although it clearly does scrub the air of suspended particles, there is some evidence that these powered filters may also help keep particles suspended in the air that would otherwise settle out. Use of this kind of filter does not remove the need for personal protection equipment - some think that because they are filtering the shop air they they don't need to use personal equipment for particle filtration, whether powered or passive PPE, etc. which is NOT the case. Your lungs will do a very efficient job of filtering your shop air long before the air passes through the box and filters (however efficient) of your powered air filter! Another myth is that this kind of air filter can replace a vacuum-based dust collection system that collects wood dust at the point source where the wood dust is generated - NOT SO!! A dust collection system is BY FAR the best way to control airborne dust.
I think the shop air filters are a bit over-rated (and over priced) for the amount of benefit they are supposed to give. I have one, and use it when a large amount of dust is generated - but under those rare conditions, I will leave the shop and keep the air filter running for at least an hour. I use my dust collection system EVERY TIME I sand or generate air suspended wood dust (like turning dry wood, sawing or routing MDF, power carving, etc.). The air filter does reduce the amount of dust settling out of the air, which supports the idea that this is primarily a "clean shop" filter rather than a "lung protection" filter. You STILL need PPE to handle the lung protection task.
Rob
Mark,
Doesn't banging it on a garbage can or blowing it out with compressed air defeat the purpose. Your putting a lot of the dust back into the air as you breath it. Better to vacuum it off of the filter IMHO.
Amen to everything that you said, Rob!
But, Rob ... if the dust is so fine that you can't see it, then it can't possibly be harmful ... or, can it?
According to the research done by the group that Bill Pentz worked with, the most harmful dust is 0.5 microns to 2 microns. These particles are too small to be filtered out before they get to your lungs and too large to be carried away by the blood stream.
Remember that shop air filters remove particles suspended in the air of the shop - the same thing that your lungs do without costing you for the electricity used. If you are generating enough dust to suspend it in your shop's air, you have a situation where efficient personal protection is absolutely necessary. I have a JDS 750 air filter that uses a 1 micron bag filter; I swapped-out the replaceable filter with a washable electrostatic filter which protects the bag filter, and also use an HVAC-style replaceable filter as a pre-filter (as has been described) to protect the electrostatic filter and to remove the largest particles first. I only use this air filter when I am not in the shop - if there is that much dust in the shop air to need a filter, I get out and let the filter do its job without any help from my lungs!
Some people have described these filters as "shop dust filters" which help keep the shop clean from dust settling out of the air, and although it clearly does scrub the air of suspended particles, there is some evidence that these powered filters may also help keep particles suspended in the air that would otherwise settle out. Use of this kind of filter does not remove the need for personal protection equipment - some think that because they are filtering the shop air they they don't need to use personal equipment for particle filtration, whether powered or passive PPE, etc. which is NOT the case. Your lungs will do a very efficient job of filtering your shop air long before the air passes through the box and filters (however efficient) of your powered air filter! Another myth is that this kind of air filter can replace a vacuum-based dust collection system that collects wood dust at the point source where the wood dust is generated - NOT SO!! A dust collection system is BY FAR the best way to control airborne dust.
I think the shop air filters are a bit over-rated (and over priced) for the amount of benefit they are supposed to give. I have one, and use it when a large amount of dust is generated - but under those rare conditions, I will leave the shop and keep the air filter running for at least an hour. I use my dust collection system EVERY TIME I sand or generate air suspended wood dust (like turning dry wood, sawing or routing MDF, power carving, etc.). The air filter does reduce the amount of dust settling out of the air, which supports the idea that this is primarily a "clean shop" filter rather than a "lung protection" filter. You STILL need PPE to handle the lung protection task.
Rob
... And so what else can one do?
My shop is the great outdoors. Don't have to worry about dust settling on stuff and I get a continuous supply of "fresh" air (as fresh as can be expected in a large city). Climate control is sort of out of my hands, but most of the time it is tolerable.
I do take it outside and I definitely put on my Dust Bee Gone mask before I start cleaning.Mark,
Doesn't banging it on a garbage can or blowing it out with compressed air defeat the purpose. Your putting a lot of the dust back into the air as you breath it. Better to vacuum it off of the filter IMHO.