Ignore Woodworking Dust Collectors At Your Peril

Not many amateur woodworkers appreciate the dangers of being exposed to woodworking dust.  However, many of us would like to solve the dust problem simply by connecting power tools to a vacuum cleaner. Before doing so, there are some basic issues to consider. To start off with, there are three main types of vacuum cleaners available – domestic, commercial and industrial.

Domestic

Generally the motor drives a small fan (1-2kW) at high speed, and the filtration system consists of a single disposable paper bag and secondary fine polymer mesh filter in the event of the paper bag leaking or tearing. Alternative designs offer units that are fitted with a cyclone to deposit the majority of the dust into a transparent receptacle, followed by one or more disposable or re-useable filters.

Commercial

They typically consist of a robust vertical cylindrical metal or plastic container (or drum) fitted with an integral motor driving a fan and runs on wheels or castors. A long suction hose is provided together with several interchangeable tools for various cleaning applications. The filter usually consists of a disposable paper bag or a re-useable cloth bag to contain the dust, within a secondary cartridge filter, which acts as backup in the event of a burst filter. The filtered air flows over the motor before it discharges into the atmosphere. This type of unit is generally used in offices, laboratories and small businesses as well as for more demanding domestic applications.

Industrial

Typically consists of a large metal dust container fitted with a dust collection bag, and a separate adjacent fan unit, with the fan belt-driven by a separate three-phase induction motor. The motor and starter may be suitable for use in a hazardous area. The unit is usually quite heavy and is mounted on a wheeled trolley, and uses a large, 50mm diameter hose connected to the suction. The filtration is usually a cyclone with a dust-containing bag, followed by a disposable paper filter and possibly another filter if toxic materials are to be trapped.

Selecting a vacuum cleaner

• The best choice of vacuum cleaner is one where the motor and electrical equipment are not in the path of the air drawn through the vacuum cleaner (this is usually only found on larger industrial vacuum cleaners with three-phase induction motors).
• Where a small commercial vacuum cleaner is to be used, then one with at least two filters and preferably three filters in series should be used.
• Do not use domestic vacuum cleaners, as they are unlikely to be robust enough to stand up to the cleaning demands of commercial premises.

Attachments and hoses

• Be careful with metal attachments.
• If metallic attachments are to be used, ensure that they are earthed.
• Avoid the use of wire-reinforced hoses. Should a wire-reinforced hose be used, make sure that the wire is earthed and is on the inside surface of the hose.

Dust bags, filters and cleaning

• Empty the dust collecting bag or container frequently to avoid overloading the vacuum cleaner.
• Change any disposable filters regularly. It is best to replace these at fixed intervals rather than rely on the discretion of the operator, as often they will not change the filter until it has burst or the vacuum cleaner fails to function properly.
• Periodically open the vacuum cleaner to inspect the motor for deposits of dust, and thoroughly clean the motor. Only qualified persons should undertake such dismantling, cleaning and reassembly.

The Ideal Solution

Purifying of the air in a workshop can be achieved through either venting the cyclone outlet outside or filtering and re-circulating the air inside. Venting outside eliminates fine dust from re-entering your workshop environment. No filter can achieve the same level of purification. Venting outside is less expensive to install, as no filtration costs apply.

The best argument in favour of re-circulating is that with venting, the discharged air has to be replaced with outside air. If your workshop is heated and especially if it is air-conditioned, then bringing the outside air to room temperature consumes a considerable amount of energy. Venting outside can be noisy and consideration should be given to near by neighbours. Also, venting outside without sufficient replacement air can be very dangerous if you have gas-fired appliances such as a water heater or a furnace in your workshop. Sufficient outside air must be allowed to flow freely into the workshop, or the flue gasses will be drawn into the air. The by-products of this combustion process contain CO (carbon monoxide), which can be fatal.

Summary

A dust collection system and an air cleaner serve two distinctly different purposes. The dust collector is designed to catch the dust at its source, filter it out of the air stream, and either filter and re-circulate the cleaned air inside or discharge it outside. An air cleaner is designed to keep the entire volume of air in the shop moving, whilst filtering it at the same time. The air cleaner will not function as a dust collector, nor will the dust collector act as an air cleaner. So, in reality you need both of them. Capturing as much of the dust at its source as possible removes most of the airborne contamination. The air cleaner finishes off the job. If you have budgetary constraints, invest in a good dust collector first.

Should you be looking to purchasing a product to solve a dust problem in your workshop, I would suggest that you visit Amazon.com where you can browse through a number of woodworking dust collectors and attachments on offer.

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