Suggestions on Air Filters?

[DeanJackson]

I bought the entry level Jet air filter awhile back; bad lungs run in the family, and I wanted to do what I can to slow that one down. (AFS-400)

I found out they discontinued it, or just discontinued selling the darn filter for it, right after I bought it. I built a small frame and fitted a $5 furnace filter after that, but was pretty darn sour with Jet for pulling that stunt. Recently, the motor cuts in and out, and with the furnace filters, it's nowhere near as effective at cleaning the air anyways. I work in a sealed basement... so this is probably the most important thing in the room.

Suggestions on air filters under $500? Shop is 1300 cubic feet. I'm debating on the floor model Grizzly (0.3 micron! 2000 cfm, $500ish) or the wall-mounted powermatic (1 micron, 1200 cfm), or anything else that's awesome and/or unlikely to die soon.

My only thing is that those are only numbers to me; does filtering sub-micron particles help my lungs? After 1000 cfm, does more airflow matter at all in a room that size? Will the Grizzly be loud enough to shake the fillings in my teeth?

[usacomp2k3]

I know that you already know this but the best way to trap dust is when it is created...

[VitalBodies]

I bought the entry level Jet air filter awhile back; bad lungs run in the family, and I wanted to do what I can to slow that one down. (AFS-400)

I found out they discontinued it, or just discontinued selling the damn filter for it, right after I bought it. I built a small frame and fitted a $5 furnace filter after that, but was pretty damn sour with Jet for pulling that stunt. Recently, the motor cuts in and out, and with the furnace filters, it's nowhere near as effective at cleaning the air anyways. I work in a sealed basement... so this is probably the most important thing in the room.

Suggestions on air filters under $500? Shop is 1300 cubic feet. I'm debating on the floor model Grizzly (0.3 micron! 2000 cfm, $500ish) or the wall-mounted powermatic (1 micron, 1200 cfm), or anything else that's awesome and/or unlikely to die soon.

My only thing is that those are only numbers to me; does filtering sub-micron particles help my lungs? After 1000 cfm, does more airflow matter at all in a room that size? Will the Grizzly be loud enough to shake the fillings in my teeth?

The smaller the particle size they list the better. It means that they filter down to that size. HEPA I think is often claimed to be .3 micron which is 3 tenths of a micron.

HEPA

They say the smaller particles do the most damage so you want to try to filter down to .3 micron if you can. This way you capture in the filter everything bigger than that.

Any time you can route the dust out of the basement do that as your first and best approach.

The 2000CFM Cubic Feet a Minute is the volume or amount of air that it will move though the filter. The bigger the number the more air is filtered.

If your room is 1300 cubic feet (make sure you mean cubic and not square) then if you have a machine that sends 1300CFM though it, you will move that much air each minute. If price does not matter you want as high of CFM as you can get. The reason for this is that fine dust is like a gas and spreads like a gas. Just because you move 1300 CF of air through the filter does not mean you moved each and every square foot of air in the shop. Some of the air near the filter will move through the filter many times before the air in the distant corners of the shop will move though the filter.

Be aware you can build one of these (DIY wood shop filter) to match whatever filter you like.

Here is one of many examples:

Example

Your Jet takes the 710621 and 710622 filters...

[Beechwood Chip]

On thing to think about: air filters are rated based on what percentage of particles of a particular size they block. The US DOE definition of HEPA is "99.97% of particles 0.3 micron in size." If you were sorting sand with a screen, you would say that the screen either catches particles of a certain size, or lets them through. But at sub micron size, it's more like catching flies on fly paper; the particles bump into the strands and stick. So, some get through.

I asked Grizzly about their 0.5 micron filter, and they said that it captures "all of them". I think they were rounding the 99.9+% up to "all". Wynn Environmental gives the actual stats for their filters. For a DIY air filter, I'd just go for HEPA rating to make it simple.

VitalBodies is correct, it's all about sucking CFMs through a HEPA filter. You also want to avoid "short circuits", where the filtered air comes out of the unit and get's sucked right back in, while the unfiltered air just hangs out.

[DeanJackson]

I know that you already know this but the best way to trap dust is when it is created...

Always worth saying again. :-)

I'm planning on updating the dust collector next, to one of the 1.5HP/110v with a canister filter. That needs to wait a few months to save up for; in the meanwhile, the air filter is just dead, so it goes first. :-)

[wilburpan]

I have and like the JDS Air-Tech 750-ER. Everyone sells a 3 speed air filter like this one. But JDS is the only company that rates the CFM of the filter with real world conditions with the filters in place. When all the other companies say that their air filters are rated at 1050 CFM, that's without any filters in place. JDS provides a peak CFM rating, but goes the extra step and rates the 750-ER at 350 cfm, 550 cfm, and 750 cfm at its three speeds with the filters installed.

As far as trapping dust at the source goes, that is the gold standard of dust control. It's also nearly impossible to achieve, which is why you need a backup plan, i.e. and air filter.

[Beechwood Chip]

One thing has always intrigued me...

I want a Dust Collector to trap the dust at the source while I'm working in the shop. It needs to have an air filter that will trap tiny particles without a lot of drag on the air flow.

I also want an air filter to run on a timer when I leave the shop, to clean the dust that's floating in the air. It needs to have an air filter that will trap tiny particles without a lot of drag on the air flow.

Is there any way to use the same filter for both, maybe with blast gates? My guess is that it's more cost effective to have two separate units each with its own filter, but it seems like a duplication of function.

Any thoughts?

[usacomp2k3]

Most of the time you are going to want 2 separate devices, partially for the simple reason that they aren't necessarily pulling from the same location. The air filters normally pull dust that is suspended in midair around the room, not necessarily around the tools. Many of them also have timers that you can leave running for N minutes/hours after you leave. If not, you can install a simple bathroom timer switch instead of a light switch for operating the air filter.

[VitalBodies]

One thing has always intrigued me...

I want a Dust Collector to trap the dust at the source while I'm working in the shop. It needs to have an air filter that will trap tiny particles without a lot of drag on the air flow.

I also want an air filter to run on a timer when I leave the shop, to clean the dust that's floating in the air. It needs to have an air filter that will trap tiny particles without a lot of drag on the air flow.

Is there any way to use the same filter for both, maybe with blast gates? My guess is that it's more cost effective to have two separate units each with its own filter, but it seems like a duplication of function.

Any thoughts?

I bought a 3HP Grizzly Dust Collector (DC) with that in mind. A 3HP has an 8 inch IN port. Most wood working machines have a 4" OUT port.

To use a dust collector efficiently there are some factors to consider:

The fine dust takes more suction than the big chunks to have much efficiency - because you are trying to grab that escaping gas like dust.

You will lose efficiency because of any corners, resistance, length or leaks in your ducting.

An 8 inch port (1570 CFM) equals four 4" ports (395 CFM).

If you have 8 inches of IN you need to have 8 inches worth of blast gates open (four 4" ports) - Otherwise you put strain on the DC (motor and your 220 volt wiring) a bit like putting your hand over the tube to your vacuum cleaner and the vacuum gets loud and hot.

With four 4" ports to burn you have options:

One port will be used up by the machine you are running.

You can use one more for "at the source" dust collection - like a port aimed at your band saw or table saw blade for example.

You can use one more port for a down draft table or wall that just sucks general dust out of the air - you could have a down draft wall/table near or as part of the machine.

You can have yet one more port open for your floor sweep or for sweeping the floor and benches (or can be open high or low or clear across the shop to catch that rouge dust - this last port can be used to "tune" the DC to make up for the lose of efficiency related to the ducting.

Ideally you want to vent the OUT of the DC out of the room because as you know, it does not catch the dust below .3 microns - plus no filter clog (loss of efficiency) or filters to buy.

Note that some DCs have timers also.

A 3HP DC is way over kill for a one man shop, and yet totally not.

Note that most filters catch the fine dust once they start to cake up.

If you you have 8" pushing air OUT of the shop you need an 8" opening to let air in and that IN can be heated or cooled using the sun or other means.

Be aware that if your DC is 8" (for example) your ideal dust collection system will maintain 8" no more or less.

MORE than 8" and the chips fall out or suspension just like in a cyclone drum and LESS you have DC strain.

If what Wilber Pan says is true "JDS provides a peak CFM rating, but goes the extra step and rates the 750-ER at 350 cfm, 550 cfm, and 750 cfm at its three speeds with the filters installed." and a 4" port is 395 CFM this you can see why having a seemingly over-sized DC makes sense.

Beechwood Chip: I have written this out in detail not because I do not think you do not know "this or that" but because others might read this also.

PS forgive any typos...

[DeanJackson]

On thing to think about: air filters are rated based on what percentage of particles of a particular size they block. The US DOE definition of HEPA is "99.97% of particles 0.3 micron in size." If you were sorting sand with a screen, you would say that the screen either catches particles of a certain size, or lets them through. But at sub micron size, it's more like catching flies on fly paper; the particles bump into the strands and stick. So, some get through.

I asked Grizzly about their 0.5 micron filter, and they said that it captures "all of them". I think they were rounding the 99.9+% up to "all". Wynn Environmental gives the actual stats for their filters. For a DIY air filter, I'd just go for HEPA rating to make it simple.

VitalBodies is correct, it's all about sucking CFMs through a HEPA filter. You also want to avoid "short circuits", where the filtered air comes out of the unit and get's sucked right back in, while the unfiltered air just hangs out.

For folks recommending dust heading outside, I live in rowhouses in a city, so that'd be relatively un-neighborly of me. :-)

Grizzly's filters: when someone says "100%", I automatically wonder if they're lying or just don't know that's not possible. Hrrm.

I'm wondering if I should buy two of the Grizzly replacement filters (inner and outer) ($150) then buy an attic fan ($100) and do this myself; wondering what other parts I'd need. Time for another thread.

[VitalBodies]

Here is something I have been pondering for a while.

Let's say I join The Guild and make an Adirondack chair out of the wood of my choice that are NOT finished with any finish.

According to Marc I would be doing some dado's, sanding, sawing and the like.

Each and every process creates dust.

If I really got this down, perhaps, I could make one every day. (Not likely, but just for conversation sake let's say I could.)

So every day I make a chair and make some dust.

To vent the dust that is missed by a cyclone DC (without the filter) outside would be how awful?

With no DC the some dust would float out of my garage also.

On the other hand:

Each day, to stay warm in my shop I could take yesterdays chair and burn it in my wood stove and vent the smoke outside - how awful is that?

Which is actually worse "relatively un-neighborly", to burn wood or make some dust?

An unrelated note: One can put the DC filter outside also (in a weather proof box).

Most people would not think much about venting a wood stove outside but might be squeamish about some dust.

Don't get me wrong, health matters as you all know, and I care about the neighborhood also.

This is not directed at anyone in particular but something I have actually wondered about for some time...

[usacomp2k3]

The difference from a neighborly standpoint is that smoke doesn't settle and cover stuff, while sawdust might. Granted most of the big stuff should be captured with a cyclone or separator, but some would still be vented outside. If your neighbors back porch is downwind of you, they probably wouldn't like a fresh layer of fine sawdust over their porch.

[DeanJackson]

Which is actually worse "relatively un-neighborly", to burn wood or make some dust?

An unrelated note: One can put the DC filter outside also (in a weather proof box).

Most people would not think much about venting a wood stove outside but might be squeamish about some dust.

Don't get me wrong, health matters as you all know, and I care about the neighborhood also.

This is not directed at anyone in particular but something I have actually wondered about for some time...

The bigger un-neighborly problem is the *noise* from venting outside; my yard (including the house!) is 25' across, so the farthest I can put a dust collector vent - and the noise from the collector venting outside - is about twelve feet from a neighbor. If I could put the dust collector outside, it'd already be done. :-)

[Beechwood Chip]

Most of the time you are going to want 2 separate devices, partially for the simple reason that they aren't necessarily pulling from the same location.

I was thinking of having two separate devices, with different motors, fans, and intakes, but sharing the filter on the output side. Using a huge Y and blast gate to control which goes to the filter. Or maybe having one going into the filter from the top, and one from the bottom, and each has a blast gate to keep the air from just passing through the filter.

Ooooh, this is beginning to sound feasible. When I install my Wynn filter on my DC, I need to build an adaptor anyway, between the DC ring and the filter. So I put a big blast gate there. And I also need to cap off the top of my Wynn filter anyway, so I put a blast gate there. I bought an attic fan intending to build an air cleaner, so I pop that on top of the top blast gate with a timer switch, and voila!

When I leave the shop, I close one blast gate, open the other, and set the timer for four hours.

My only concern is that the air cleaner may "short circuit", when the fan just sucks up the clean air coming out of the filter. I might want to build a BIG, low resistance duct out to the center of the room. [EDIT - or put an oscillating room fan on the same timer, to stir the dusty air up.]

Oh, and ceiling height. I might have a problem there. I'll need to check.

[DeanJackson]

I bought the entry level Jet air filter awhile back; bad lungs run in the family, and I wanted to do what I can to slow that one down. (AFS-400)

I found out they discontinued it, or just discontinued selling the darn filter for it, right after I bought it. I built a small frame and fitted a $5 furnace filter after that, but was pretty darn sour with Jet for pulling that stunt. Recently, the motor cuts in and out, and with the furnace filters, it's nowhere near as effective at cleaning the air anyways. I work in a sealed basement... so this is probably the most important thing in the room.

Suggestions on air filters under $500? Shop is 1300 cubic feet. I'm debating on the floor model Grizzly (0.3 micron! 2000 cfm, $500ish) or the wall-mounted powermatic (1 micron, 1200 cfm), or anything else that's awesome and/or unlikely to die soon.

My only thing is that those are only numbers to me; does filtering sub-micron particles help my lungs? After 1000 cfm, does more airflow matter at all in a room that size? Will the Grizzly be loud enough to shake the fillings in my teeth?

Built one myself, thread is here: http://woodtalkonline.com/topic/4025-diy-air-filter-plan/