It’s a simple fact. The more time you spend in your shop, the more dust you inhale. For maximum dust control we recommend using an ambient air cleaner in conjunction with a primary dust collection system, supplemented by personal dust protection when appropriate.
An ambient air cleaner, which you can run intermittently throughout the day to filter the small, suspended air particles out of the air circulating in the shop.
When setting up or expanding a workshop, the purchases that are often at the top of a shopping list are likely to be machinery or power tools. Nothing wrong with these choices, after all, these are the tools that turn our dreams into reality – we quickly see the results of our labour. However, it is important to give more than cursory thought to the by-product of woodworking (chips and dust) and how to effectively deal with them.
A primary dust collection system, whether a portable shop vacuum, a stationary bag collection dust collector, or a high efficiency cyclonic collector, is fundamental to all shops. Running hoses to your machinery and collecting chips and dust at the source can go a long way to preserving peace in the home and safety in the shop.
Regardless of how efficient your primary dust collecting system is, it won’t pick up all the dust in your shop. And, of course, it will only pick up chips and dust when it’s turned on. But what about those activities, like sanding, that we usually undertake when the dust collector is turned off? Remember, dust will not only play havoc when it comes time to applying finishes, it also takes a toll on your health. Even if your power sander is hooked up to a shop vacuum, a fair amount of dust will fill the air, and that dust is not a friend to your lungs. Dust particles work their way into the tiniest recesses of your lungs, and because of their minute size, they are not expelled through the normal respiratory processes. This can lead to a range of health problems. The solution is an ambient air cleaner, which you can run intermittently throughout the day to filter the small, suspended air particles out of the air circulating in the shop.
A lot of dust collectors still come equipped with 5 micron bags. A 5 micron dust particle can remain airborne for up to half an hour – plenty of time to end up in your lungs. However you can purchase high performance bags that filter material down to 1 micron in size. That’s a 500% increase in protection.
Air cleaners are designed to be hung from the ceiling and will filter the air in your shop on a continual basis. There are two criteria you need to factor in when sizing an air cleaner for your workshop – the number of times you want to be able to completely filter the air in the shop, and the capacity of the air cleaner. In most home workshop situations, you will want to filter the air between six and eight times per hour. To calculate the volume of your shop, multiply the length by the width by the height. Multiply this number by the number of times per hour you want to filter the air (6 – 8) and divide the result by 60. This will give you the CFM required for your workshop. Match this to the output of the various air cleaners on the market to find one sized adequately for your shop. For example, a 20′ by 22′ shop with 8′ high ceilings has a volume of 3,520 cubic feet (20 x 22 x 8). An air cleaner with at least a 352 CFM rating would be required to circulate the air six times per hour in this shop (3520 x 6 ÷ 60).
Air cleaners are very basic machines; a metal or plastic box with a pre-filter at one end, a bag filter and motor in the middle and an diffusing filter at the other end. The pre-filter on the Delta 50-875, JDS A750ER and Steel City 65100 and 65105 are electrostatically charged. This creates an attraction between the filter media and the dust that helps trap small particles that would normally travel through the larger openings in the outer filter. If you place your hand over the filters you won’t notice a lot of suction. These units require the dust to be suspended in the air, and rely on the air currents to bring the dust to the filters. As a result, placement of the unit is critical for it to function at peak efficiency. While there isn’t much suction at the input, the output air is moving fairly quickly. Correctly positioning the air cleaner will help to establish a circular airflow pattern that will help deliver the suspended particulate to the filters.
In a rectangular shop, position the air cleaner along one of the long walls, about one third of the way along the wall to the intake filter. Hang the unit from six to 12 inches out from the wall. Some of these models come with mounting hardware; with others you will have to source the lag screws and hooks yourself. In a square room, place the unit along any wall using the same criteria, and if your shop is irregular in shape as some basement workshops are, you may need a second unit to provide adequate circulation and filtration. Try to locate your dust producing activities close to the intake side of the air cleaner for the most efficient operation.
Early models came with a simple on/off switch on the end of a pull chain, but modern electronics has caught up in the workshop and some of these now sport infrared remote controls. Models like the Steel City 65105 can be turned on remotely from anywhere within the shop; the remote control also allows you to select the fan speed as well as set the automatic timer.
The larger stationary air cleaners offer multiple fan speeds to suit different situations. When you are involved in very dusty operations like sanding, the top speed provides maximum air filtration but in the process it also generates a fair bit of noise. This may be okay when you are already wearing hearing protection for a power tool, but it can be a bit too much when you are concentrating on hand work, and the cleaner is operating in the background. Having the ability to switch to a lower setting when maximum speed is not required can be a valuable feature.
A micron is roughly 1/25,000”. Which is very small. About the smallest thing we can see is 50 microns. Large dust particles of around 100 microns are heavy enough to quickly settle; it’s the fine dust, around 1 micron and smaller in size, that you want to avoid breathing in. Along with dust, many woods, particularly exotic species, contain allergens and toxins that can be under 1 micron in size. Finishing compounds found in many shops contain volatile fumes, in the .01 to 3 micron size, that can be dangerous to breathe as well. If you use a shop vacuum consider installing a HEPA (High Efficiency Particulate Air) filter, which removes particulate matter down to .3 microns.
To maintain the efficiency of the filter media, it should be cleaned on a regular basis. As the media clogs up with particulate, its resistance to the passage of air increases. The filters are designed to be cleaned and reused. At the end of every dusty woodworking session use a shop vac to clean off the dust that has accumulated on the outside of the pre-filter. After a while, the bag filter will also be coated with dust. Remove the pre-filter and use a vacuum with a crevice tool to get into the inside of the pleated filter bag. Turn the air cleaner on to inflate the bag which will make vacuuming out the inside much easier as the bag will be open and expanded to its full size. Vacuum the diffusing filter as well.
A few models (Steel City 65105, Delta 50-875) have an air flow gauge to indicate the flow of air through the unit. This is accomplished by placing a vane in the output airflow that is tied to a pointer on the outside of the unit. These gauges are designed to indicate the efficiency of the unit. As the filters get blocked with particulate the flow of air is reduced and with a quick look at the indicator you can tell if the filters need to be cleaned. A timing feature found on a number of models (Craftex CT-051, Delta 50-875, JDS AT750ER, General 10-550 and 10-660, King Canada KAC-650, and Steel City 65105), turns the machine off after a specified period of time. After cleaning up the shop at the end of the day you can set the timer to run anywhere from 1/2 hour to four hours after which it will automatically shut off. If you do any amount of sanding in your shop, then you owe it to yourself to consider installing an ambient air cleaner. It will keep your shop dust free and your lungs healthy.
So, which air cleaner to buy? For the budget conscious shopper, the Craftex B2055 or Steel City 65100 offer good value. The hobbyist woodworker might want to consider the Delta AP200 or King KAC-650, which cost only a few dollars more, but have a wider range of features. The woodworking enthusiast or professional woodworker has the widest range of models to choose from, including the Delta 50-875, General 10-600, Steel City 65105 and JDS AT-750ER. At the higher price range you can get a unit that offers the convenience of a remote control, multiple speeds, and an electrostatically charged pre-filter.
If you do a lot of power sanding you know how much dust can end up in the air. A downdraft sanding table, like the General 10-710 (general.ca), connected to a shop vacuum, will significantly help reduce air borne dust.
If you have a very small shop and don’t run a lot of machinery, or you do a lot of on-site work, then consider a small portable air cleaner, like the Shop Vac 103-00 (shopvac.ca). It’s designed to be taken to the source of the dust and can be placed directly on a work surface, or on the floor, in close proximity to the dust source.
|Steel City 65100
|Steel City 65105