Homemade Air filter vs Jet

[Ed Gibbons]

Is a Jet air filter better than making one myself?

Is there a big difference between the Jet 1000 & 2000?

Thanks.

[PHILIP MACHIN]

I have the Jet 1000 and it is pretty much a pretty version of a HEPA filter strapped to a box fan. I’m sure you could accomplish the same thing, it just won’t look all fancy.

[Stan Calow]

I'm pretty sure I saw one of the woodworking magazines publish a product test review last year, in which a box fan and filter came in third in performance amongst a large group of them. Maybe someone else saw that article and can confirm.

[michael dilday]

I have a Jet 1000 AFB and it is a great air filter. I use FPR 7 pre-filters from the big box stores and the inside filter is a Wynn filter with specs
MERV 14 95% ASHRAE (99.6% at 5.0 microns, 92% at 1.0 microns, 79% at 0.5 microns). I would question whether a box fan could move enough air with a filter capable of .5 micron particles but I am no expert.

[Jon Nuckles]

I have the Jet 1000 and it is pretty much a pretty version of a HEPA filter strapped to a box fan. I’m sure you could accomplish the same thing, it just won’t look all fancy.

I have the Jet, too. I believe it is a squirrel cage fan. I think that makes a difference, but am not versed enough in the technology to know how much.

[Malcolm McLeod]

I have the Jet, too. I believe it is a squirrel cage fan. I think that makes a difference, but am not versed enough in the technology to know how much.

For equivalent air flow, a squirrel cage fan is significantly quieter than a axial fan (typical of 'box' fans). As I understand it, this is why squirrel cage dominates in HVAC designs - they don't keep you up at night.

[Frank Pratt]

I have a Jet 1000 AFB and it is a great air filter. I use FPR 7 pre-filters from the big box stores and the inside filter is a Wynn filter with specs
MERV 14 95% ASHRAE (99.6% at 5.0 microns, 92% at 1.0 microns, 79% at 0.5 microns). I would question whether a box fan could move enough air with a filter capable of .5 micron particles but I am no expert.


Those filter specs are a little frightening. After leaving the filter running for 1/2 hour or so would leave one with the impression that the air is clean. But all that sub-micron (the most dangerous particles) stuff is just being stirred around & kept suspended by the thing that's supposed to filter it.

Dust collection/filtering should do one or both of two things: 1) crude collection that keeps the work space cleaner, 2) filters out the harmful particles. A ceiling hung filter unit should do the latter, but that Wynn filter does neither.

[Frank Pratt]

For equivalent air flow, a squirrel cage fan is significantly quieter than a axial fan (typical of 'box' fans). As I understand it, this is why squirrel cage dominates in HVAC designs - they don't keep you up at night.

The main reason for the squirrel cage fan is that they develop higher static pressure, which is needed to pass the air through the filter.

[Ed Gibbons]

What filter is best?

[Andrew More]

A lot of the store bought filters have remotes, which is really nice when it's hung up high. Personally I build a box with a HVAC blower, and ran a switch to it, but some people might not feel comfortable with that approach.

[michael dilday]

Those filter specs are a little frightening. After leaving the filter running for 1/2 hour or so would leave one with the impression that the air is clean. But all that sub-micron (the most dangerous particles) stuff is just being stirred around & kept suspended by the thing that's supposed to filter it.

Dust collection/filtering should do one or both of two things: 1) crude collection that keeps the work space cleaner, 2) filters out the harmful particles. A ceiling hung filter unit should do the latter, but that Wynn filter does neither.

I have a Dylos air quality meter. It measures small particles down to .3 microns. Believe me with the Wynn filter the air is clean.

[Bruno Jean]

Micheal,

Can you post some of the reading you get from your Dylos in different configurations?

[Gary Ragatz]

I'm pretty sure I saw one of the woodworking magazines publish a product test review last year, in which a box fan and filter came in third in performance amongst a large group of them. Maybe someone else saw that article and can confirm.

Wood Magazine published a review last summer. The two Jet units were both awarded "Top Tool." The box fan was awarded "Best Value." The box fan setup, using a MERV 12 filter, came in 4th overall, in terms of how quickly it cleared the air in a "test shop." It took about 5 times as long as the Jet units (61 minutes vs. 13). There were seven other products in the comparison - a couple of Grizzlies, a couple of Powermatics, a Rikon, a Shop Fox and a Supermax.

[michael dilday]

Micheal,

Can you post some of the reading you get from your Dylos in different configurations?

I can post a reading from the Dylos. Not sure what different configurations you are referring to though.

[michael dilday]

The main reason for the squirrel cage fan is that they develop higher static pressure, which is needed to pass the air through the filter.

What Frank said.

[Bruno Jean]

"Not sure what different configurations you are referring to though."

Like when you cut thin wood, thick wood non through cut, dado, maybe planing,

Thanks

[Andrew Seemann]

I have a home built air filter I made about 20 years ago, and a generic commercial one (Woodtek maybe?) that I inherited from the old man. When I built the original one, I had the squirrel cage blower on hand. Given the effort to build one and the extra weight due to using 1/2" plywood vs thin sheet metal, I would probably buy one rather than build one. Not to mention the fact that the one I built doesn't have a nice, insurance-friendly UL sticker on it in the event that the shop catches fire. I probably will eventually replace the one that I built with a commercial one that has one of those cool timer features that runs it 10 minutes every hour.

I will say that having 2 air filter units in a 24x28 shop clears the air in a hurry.

[Bruce Wrenn]

I built my own, using a 1/2HP squirrel cage fan, three bag inner filter., and a high eff. outer filter. Best thing I ever did, is in colder months, added a thermostat mounted on ceiling over shop heater. Heat comes on, so does air filter, circulating heat over whole shop. During warmer months, I use a "Christmas Tree" remote to control fan.

[michael dilday]

"Not sure what different configurations you are referring to though."

Like when you cut thin wood, thick wood non through cut, dado, maybe planing,

Thanks

I am not sure that variable is relevant for evaluating an air filter performance. The amount of dust in the air not captured at the machine and how quickly it is removed by the air filter is what matters.

[Wayne Cannon]

For what it's worth, go for it! When I had my heat pump installed (it's an overhead unit hanging from the ceiling), I asked the HVAC guy if he could make a filter box for the same pocket filters that my Jet air filter uses. His sheet metal guy made one and they put it on the intake end of the heat pump. It was inexpensive -- they do that kind of special sheet-metal boxes, plenums, adapters, etc. all the time -- and uses exactly the same filters as my Jet. I don't have any quantitative information, but since the filters are the same and the amount of air moved is similar or more, it should be at least as good (ignoring positioning as a significant factor).

[David L Morse]

"Not sure what different configurations you are referring to though."

Like when you cut thin wood, thick wood non through cut, dado, maybe planing,

Thanks

I am not sure that variable is relevant for evaluating an air filter performance. The amount of dust in the air not captured at the machine and how quickly it is removed by the air filter is what matters.

Michael, perhaps he's thinking about the steady state condition where the rate of dust production is relatively constant for a longer period of time. The amount escaping the collection hood may vary with the operation type and thus the equilibrium concentration in the air will vary, depending upon the filter/fan performance, the source collection efficiency, and the particle size distribution of the dust.

[Tom Dixon]

Michael, perhaps he's thinking about the steady state condition where the rate of dust production is relatively constant for a longer period of time. The amount escaping the collection hood may vary with the operation type and thus the equilibrium concentration in the air will vary, depending upon the filter/fan performance, the source collection efficiency, and the particle size distribution of the dust.

Doesn't Big Dust Theory show that the cosmic rate of dust generation is constantly accelerating disproving Steady State Dust Condition Theory?

[Malcolm McLeod]

Doesn't Big Dust Theory show that the cosmic rate of dust generation is constantly accelerating disproving Steady State Dust Condition Theory?

Your postulate is based on Quantum Dust and was superseded by Nano-String Dust Theory. Clearly.

[Tom Dixon]

Your postulate is based on Quantum Dust and was superseded by Nano-String Dust Theory. Clearly.

A Multi Dustverse... Fascinating!

[David L Morse]

Doesn't Big Dust Theory show that the cosmic rate of dust generation is constantly accelerating disproving Steady State Dust Condition Theory?

Sorry Tom. I tried to keep it simple by leaving out the math. Should I be more rigorous?:D

[Tom Dixon]

Sorry Tom. I tried to keep it simple by leaving out the math. Should I be more rigorous?:D

By all means yes. Just be sure to use millimeters and decimals. I've sworn of Imperialistic fractions. :p

[Jack Frederick]

My JDS 2000 has a 1" pleated filter on the inlet. Inside it has the bag filter. The bag is designed to maximize the amount of filter area. Then, a small motor and squirrel cage blower. It works well and would be easy to build, if you source your filters correctly. You could get a Dwyer manometer or digital to read static pressures at the inlet and outlet. Mark the original readings with a sharpie on the box. Check it periodically and you will know when it is time to replace the small pleat. The bag filter should last quite along time for a hobbyist. I carefully cleaned mine with a vacuum and air compressor, gently, over the years. A question for the group, what HP motor are you running on your boxes?