There are many dust control strategies and the most effective are often the simplest. The hazards are increased when dust is concentrated into an enclosed area. Because of this opening a door, window, or garage door can have a big impact. Even more effective is to use a fan to blow the dust out. You can also work outside for especially dusty operations.
Masks & Respirators
Dust masks and respirators are an important part of personal protection in a workshop. Even if you’re working in a well-ventilated shop (or outside) you still need to wear protection. The most common masks are the disposable white cloth masks. These offer some level of protection but are porous and allow small particles to pass through. They should not be used when working with chemicals, as they can’t filter them out.
The second level of protection is a professional respirator. This is a rubber mask that has replaceable canisters. The canisters can be changed for different operations. Canisters for filtering out dust particles are typically made with pleated sheets of filter material.
Chemical filter cartridges typically have carbon in addition to the particle filters. These are useful when working with finishes and chemical strippers. They have a limited lifespan so please read the directions before using.
When using a respirator, it is important that it is fitted properly to prevent air from leaking in around the edges. Read the instructions carefully for proper fitting. As a rule, when working with a respirator, if you can smell the dust or chemicals, you have an air leak.
Air cleaners (a.k.a. Air Polishers) are used to continuously filter the air and remove small particles. They are useful for removing the very small dust particles that escaped your dust collection systems. An air cleaner is a good addition to an already existing system, but you should put your efforts and money first into controlling dust at the source as well as preventing it from getting into the air in the first place. Air cleaners are also useful for cleaning the air to an extra degree if you are trying to achieve an ultra-fine finish.
Tool Dust Collection
As we mentioned above, you should try to control the dust at the source, and tool-based dust collection is the best initial strategy. Many of the tools on the market today offer dust ports and, in some cases, built in dust bags and filters. The dust filters and bags work well but can allow small particles to pass through. The best strategy is to use a hose that connects to the tool’s dust.
A shop vac or stationary system can then be fitted with HEPA grade <1-micron filters. This not only helps to control dust, but also in the case of sanding, can lengthen the life of your sandpaper and make the process go faster. If you have a vacuum system, we recommend you upgrade the filter and keep it clean. In our shop, we keep two filters on hand so that we can quickly replace the filter, wash out the dirty one, and allow it time to dry.
Shop vacuums are very effective at controlling dust. As mentioned above, go ahead and upgrade your filter for the best results. Shop vacuums can be used to suck up dust and wood chips in the shop. They can also be connected directly to hand and stationary shop tools to collect dust. When connected to tools they should be turned on before and after the tool is used. When working with chip producing tools such as a planer or router they may require frequently emptying.
Dust collection systems are ideal if you have a large workshop or do a lot of woodworking. The stationary dust collector can be setup out of the way and tied into all your tools through a central collection line. The systems allow for the use of various fittings and options such as floor sweeps.
Single Stage Dust Collectors
Single stage dust collectors are designed to suck dust and debris into filter bags. They are called single stage because all the materials are sucked through an impeller on their way to the filters. The primary disadvantage of this, is that the impellers must be made bigger and stronger to withstand the impact of the debris. The larger impellers tend to be noisier and require more power to turn.
Dual Stage Dust Collectors
In a dual stage system, the debris first enters a cyclone separator chamber where the large debris is separated from the fine dust. The fine dust then moves on to the filter bags. Because only the dust is passing through the impeller, it can be lighter weight. The filter bags in a dual stage collector are designed to filter out dust (not chips like a single stage). They are often made to <1-micron standards vs. 5 microns for a single stage filter.
Various pre-separators are available and can be added on to a single stage system to help remove large chips. The separators are typically a plastic cap designed to be fitted onto a metal trashcan. The area within the trashcan allows the large chips to “fall out” and collect at the bottom allowing the fine dust to travel on to the dust bags. While not as efficient as a dual stage system, a pre-separator is a great add on. You will typically experience a static pressure loss with these systems though.
Filter bags are available in a wide range of sizes and filter ratings. The filters are rated in microns referring to the smallest particle size the bag can filter out. One micron or less is ideal for a shop filter. Most systems come with bags around 5 microns.
Whole Shop Systems
Setting up a whole shop dust collection system is the ideal way to collect and control dust from the point of origin. With a whole shop system, a main line is run with lines branching off to each piece of equipment. Blast gates are used to control the flow from each machine. If you’re considering purchasing a dust collection system, you should design the layout first to ensure you purchase the right size collector. See the resources section at the end of this article for a couple of good books on the topic of setting up a dust collection system. They cover subjects such as pressure calculations, static pressure loss, main lines, etc.
Piping – Metal vs PVC
The piping you use in your shop is an important consideration. As sawdust moves through the pipe at high velocities it will create a static charge that needs to be dissipated. This prevents shocks as well as the potential for an explosion. Properly grounded metal piping will dissipate the static charge. PVC pipe can also be used but it must be wrapped with a grounded bare copper wire on the inside and out. If you use any plastic fittings (such as a blast gate) on metal piping you need to attach a copper jumper wire to bridge the fitting and continue the ground. We offer a copper wire grounding kit complete with the wire and fittings you need. You can also purchase the materials from an electrical supply house.
Dust hoses are typically made from a soft flexible plastic and are helically wrapped to help them stay open. The dust hoses are used to connect equipment to the piping. They also help prevent machine vibration from traveling into the piping. You can use a longer piece of collection hose to allow for movement of the machine. Smaller hoses can be run from the system to hand power tools.
Dust hose are available in clear and black anti-static. The clear hoses allow you to see any clogs but need to have a copper wire added on the inside and outside for static dissipation. The anti-static hoses have an additive in the polymer that allows them to conduct the static and do not require a grounding wire.
Blast gates are used to control the flow of air from the main line to the machines. By opening a blast gate suction can occur at that machine. You should only open one gate a time unless your system is designed for multiple machine to be operated at the same time. (This is typically only done in larger commercial shops.)
The blast gates are available in aluminum and plastic. The aluminum gates are more durable and do not require a grounding wire. The plastic gates are more economical but require a grounding wire to jump the grounding around the gate.
Various clamps are available for dust collection systems. Wire clamps are the most economical and are ideal for multiple connections. Steel band clamps work well when a more secure connection is required. Key hose clamps are used for connections that need to be removed frequently.
Various fittings are available for connecting hoses together. Y-Fittings, T-Fittings, Splices, Elbows, and others are also used to layout a system. Other fittings are available for reducing and enlarging hoses to allow them to connect to tools and other systems. Specialty fittings such as floor sweeps and lathe dust collection hoods are also available.