Introduction.
I figured it was about time to get serious about dust collection and filtration. I looked out the door into the sunlight the a while ago and the amount of suspended dust I could see gave me cause to think.
The dust sizes that woodworkers typically have to worry about are from 0.4 microns to about 8 to 10 microns. There are a number of sites that give some excellent information on dust collection, perhaps the best is run by Bill Pentz. If you have only a little time to read today, I suggest you leave this review now and read Bill Pentz's introduction instead - it may lengthen your life.
Generally, hand tool users have little risk to dust in the workshop. It mostly comes from machines. Blunt blades will create more dust than sharp ones. Table saws, routers, jig saws, drills, morticers, jointers, thicknessers etc all eject massive amounts of fine dust - Bill Pentz says nearly 5% of dust created is the fine invisible dust (the 'bad' dust). A note for hand tool users though, shavings and other timber pieces laying on the floor are slowly ground to dust and kicked into the air as you walk on them. If you like a workshop with 'atmosphere' you may want to consider the ramifications for your health.
There is no single solution to the dust problem, it needs a staged approach to minimise the risks to the woodworker. First you have dust extractors, then air filters and finally dust masks. Note that the single best way to avoid dust is to get it at the source, use a good extractor and eject the air outside the workshop (but away from neighbors please) and to also wear a suitable dust mask capable of capturing down to 0.4 micron particles. Unfortunately, once you take off your dust mask you immediately begin to inhale the fine dust you have tried so hard to avoid; this is where the air filters come in.
Despite your best efforts, fine dust will escape the dust collector and become airborne in the workshop. You cannot see this dust and it floats on the air currents. When you inhale it goes into your lungs. If it is larger than 0.4 microns it cannot pass through the lung wall and be ejected by normal bodily functions, therefor it sits in your lung.
A good air filter will rapidly process large volumes of air, removing particulates down to 0.4 micron. The key is to get a filter that will remove the smaller particles and that can also process the air in your shop quickly enough to minimise the exposure you have to the fine dust.
Selection.
I only looked at two styles in detail, these were the large rectangular roof mounted units from Jet and Carba-Tec and the Microclene MC1000 (click on the pictures to go to the websites).
http://www.carbatec.com.au/images/th...s/CTF-1000.jpg http://www.microclene.com.au/assets/...1000_small.jpg
My workshop is 5.6 x 6.0 x 2.7m. The primary requirement was to filter the 90 cubic metres of air about 10 times per hour. Secondary needs were for it to be small (2.7m ceiling and I am 188cm), mobile and relatively cheap to run. The reasons I chose the Microclene MC1000 were:
- It removes 65% of particles down to 0.5 microns and 95% of 1 micron particles.
- It can filter the air in the workshop over 10 times per hour,
- It is small and easily moved,
- It is a 100W motor so is efficient to run.
Even though the Jet and Carba-Tec units had better flow rates their filtration is not as good. The Jet and CT units each claimed 98% of 5.0 micron particles and 85% of 1.0 micron particles. The Microclene started at 95% of 1.0 micron particles and went down to 65% of 0.5 micron particles, the only one to concentrate on the really fine particles.
Flow rates
Microclene MC1000 = 1000 cubic meters per hour
Carba-Tec 650cfm = 1104 cubic meters per hour
Carba-Tec 1700cfm = 2888 cubic meters per hour
Price.
The Microclene was not cheap at $765 (it shipped with a complimentary $27 spare filter), but since the other units did not remove the damaging dust below 1 micron they did not meet the required specification and were (arguably) more expensive in the long term health-wise. The smaller CT unit was $459, the larger was $899.
MC1000 Review
Finally, on to the review. The unit was ordered as a Christmas present and shipped on time. Dealing with the company was easy and very helpful indeed (according to my son).
Shipping. The parcel was shipped in a well protected and very clearly labelled box and arrived in plenty of time for Santa to wrap.
Instructions. These were clear and concise, they are also downloadable from the web in PDF format. There are some very minor issues with the manual: it uses the term "mcfb" repeatedly without explaining what it is. I assume it is micro-clene filter box or similar. There are typos e.g. "sgrew" (screw) and they do not explain the filter cleaning at all. Is it possible to wash or clean the filters, or should they be replaced? I have read elsewhere there are people who are vacuuming the filter and continuing to use it. It would be nice to know whether this is a safe practice or not. I suspect it isn't, as the filters will load up with small particles and become less efficient. In addition, the vacuum used to clean the filter is unlikely to have a filter as good as the Microclene, therefore it will simply pump it all back into the air for you to breathe, which obviates the reason you bought the unit for in the first place. EDIT: Regarding the cleaning of filters; the distributer advises that used filters should be replaced (for the reasons mentioned) rather than cleaned. Vacuuming or blowing with compressed airis not endorsed. Filters should not be washed. Replacement of filter is easy to do and is much safer to simply discard used filter in sealed plastic bag.
Installation. Setup was very simple, initially I hooked the unit onto an existing ceiling hook, plugged it in then turned it on. Later I welded up a few overhead bars near the lathe and tablesaw for it to hang from. EDIT: The correct way to install is via TWO suspension points or using the mcfb bracket available from the supplier. I have included a photo of my installation below.
Attachment 100030
Functional test. On startup you can see the torque twist the unit to the left as the motor spins up to operating RPM. There is a warning in the manual that the unit can unscrew a twist-style hook after multiple starts due to this torque effect.
It appears to work just as advertised. At the tablesaw I can feel the air being drawn from behind me, picking up the dust and then cleaner air blowing across the roof over my head. Unfortunately I cannot measure the size of particulates are being sucked up and will have to accept their claims to meeting the standards in that regard. The unit is a little noisy but it is air noise, not mechanical noise, and to be expected.
The unit hangs from my low ceiling and doesn't hit my head, so that is a plus :2tsup:. It is only 22.5 cm high and 30 cm in diameter so it takes very little room. I noticed the cable is the same as a computer monitor cable so loss or damage will be easily and cheaply replaceable.
At the end of a day of using the tablesaw, thicknesser, sander, jointer and dust collector the air felt clean. For once I was not blowing home made dowels into my hanky and that indicated my lungs were also clean (er). :2tsup:
Hidden benefit. :)
I have found that in use the unit doesn't just filter the air, it also cools my workshop. Most other units suck in air at one end of a box and pump it out the other so the air remains in the same plane. The MC1000 sucks air in the bottom then blows it out the sides near the top of the unit, creating a rising column of air. This sucks cool air from the floor and blows it across the roof, forcing the hot air out of the shed. It is so comfortable that I find I turn the unit on just for its cooling effect and no longer use my other fan; therefore offsetting the air filter operating cost with fan running costs.
Likes:Dislikes:
- Filters down to 0.4 micron.
- Cools the workshop
- Small size
- Cheap to run
- Simple, no fuss unit.
Summary.
- Cost, this unit is expensive at $765. To be fair though, the other units I looked at did not filter to the same degree so a direct comparison on cost is unfair to the Microclene.
- Minor omission from the manual about cleaning the filters.
Once I get over the cost (ouch) it does everything I wanted it to do and more. The cooling of the workshop is a big plus for me, I have a low metal roof and I get a large amount of heated air from the shoulders up. This unit solves that problem and also means I do not have to run the other cooling fan that I normally run, so there are cost savings too. Its portability means I can easily move it to be overhead my lathe, workbench or tablesaw with very little fuss.
Bottom line - a well designed machine that will get a lot of use in my workshop.