With the arrival of our new Magnum Industrial dust collectors, we thought that it would be a good time to review the basics of choosing and setting up a dust collection system.
An effective dust collection system is an important component of every clean and safe woodworking shop. To make this happen, you need to plan ahead, carefully review your dust collection needs and choose the equipment that suits your shop.
To Duct or not to Duct
For some woodworkers, a dust extractor will meet their needs. Dust extractors are powerful and portable, and they provide point-of-origin dust collection for mitre saws, jobsite table saws, track saws, sanders and grinders equipped with the appropriate vacuum shroud. Unlike a shop vac, dust collectors are designed to move fine particles. Many have HEPA filters, anti-static hoses and tool-activated power switches.
If you use a table saw or disc sander, which can require up to 400 and 450 CFM respectively, you’ve already outgrown your dust extractor. But small shops don’t necessarily need big dust collectors.
KMS sells a variety of 3/4 and 1 HP portable dust collectors that pull between 450 and 700 CFM and can connect directly to your machine.
“Don’t plumb in a 1 HP dust collector,” says Lyle Glasgow, a woodworking specialist at KMS in Coquitlam. “If you have a small shop with two or three pieces of machinery, use a 4″ or 5″ diameter hose up to 6′ long and move your dust collector from workstation to workstation.”
If you have a large shop (or plan to expand), operate two or more pieces of machinery at the same time or want to avoid disrupting your workflow with moving and connecting a small dust collector, choose a larger collector (1 1/2 HP or higher) and install ductwork that fits your shop and workflow.
Duct Diameter and Distance
The first step is determining the CFM requirements of each machine in your shop. This chart, courtesy of Oneida Air Systems, shows the typical CFM demands for common woodworking machines.
The next step is finding the best place for your collector. If possible, find a location that doesn’t disrupt your workflow. From there plan the ductwork to each workstation and then go out and buy a collector that meets your shop’s requirements. Your collector needs to provide enough CFM for each machine running in your shop. So if you plan to operate two machines simultaneously, your collector must be able to haul in debris from both machines. For example, if you have a table saw that demands 450 CFM and a planer that needs 800 CFM, your collector will need to handle at least 1,250 CFM. Your collector’s performance is also affected by the diameter and length of your ductwork, factors that play a significant role in the overall effectiveness of your system.
Dust collection systems need to balance air volume (measured in cubic feet per minute or CFM) and velocity (feet per minute or FPM) and limit static pressure (SP). The air travelling through the ducts must maintain enough velocity to keep the dust and chips in the airstream—that’s 4,000 FPM in the branches and 3,500 FPM in the main line. If velocity diminishes, the debris will fall out of the airstream and build up inside the ducts. Decreasing duct size improves velocity but also increases friction, or static pressure (SP), which affects the volume (CFM) of air being moved. Systems that move less CFM collect less dust. Try to take a direct route to each machine, avoid tees and hard 90 degree elbows, and limit curves, bends and flex hoses. Each shop poses unique challenges—there is no cookie-cutter solution. You should build a system that works for your shop and budget.
If you’re looking for more information about why duct size matters, check out this helpful tutorial from Oneida. You can also pick up a copy of Dust Collection Basics. It has a handy table to help you calculate the right balance between volume (CFM) and velocity (FPM) for your shop.
You Can’t Get No Static-Faction
Some folks like to use sheet-metal ductwork, while others prefer PVC pipe. If you plan to use the latter, consider grounding your system. Wood and dust particles create static electricity, and because plastic pipes aren’t conductive, a static charge can accumulate and release with sometimes shocking results. To connect each machine to the main duct, consider using clear plastic hose, which we offer in both 4″ and 6″ diameters. This hose lets you easily spot clogs and is wire-reinforced, which helps ground your system.
Whether you use metal or PVC, connect your ductwork with screws so you can access individual sections for down-the-road maintenance. Seal the connections with foil tape or duct sealant and make sure there are no leaks.
Filters and Bags
Most bag-style dust collectors come equipped with a top filter bag rated between 35 and 1 micron(s). Because fine dust particles are often the most harmful to our lungs, it’s important to check the micron rating before you buy your collector. It’s also not a bad idea to wear a respirator—especially if your machine has a more porous filter, i.e, anything above 10 microns. Also wear a respirator whenever you empty the bag or canister.
After awhile, a layer of fine dust will cake the inside of your filter bag. This dust, or “cake,” will affect the performance of your system: The right amount of cake works like an additional filter, removing fine dust particles before they reach the filter bag. Too much cake, however, will restrict the airflow. Keep an eye on the build up, and regularly clean out your filter bag.
In lieu of a bag filter, many collectors can be fitted with a 1 micron pleated canister filter that delivers more surface area and better filtration. “The machines we stock come with a bag or with a canister filter,” says Glasgow. “Bags have less surface area and wear out faster. Canisters are easy to clean, perform well and last a long time. When you buy your dust collector, upgrade to a canister. It’s better long-term value than buying a machine with a bag-style filter and upgrading to a canister once the bag wears out.”
If you want to upgrade your existing dust collector with a better filter, KMS sells optional filter bags and canister filters. Remember that canisters and bags with high micron ratings will reduce a collector’s CFM performance, an important consideration for those upgrading an older collector with improved filter media.
Dust Deputy and the Cyclone Kid
Another cost-effective upgrade–especially for smaller shops–is a cyclone pre-filter or Dust Deputy, which removes larger chunks and chips before they reach the collector. The benefit is twofold: fewer bag changes and better performance. Oneida’s Dust Deputy features design elements similar to those found in two-stage cyclone dust collectors, which are some of the most powerful and efficient dust collectors available.
“Are cyclones a better system?” asks Glasgow. “Absolutely. A 1 HP cyclone is about as efficient as 2 HP bag-style collector.”
While bag-style machines draw everything through the impeller, cyclones separate the larger pieces from the fine particles, allowing them to use impellers that are designed to efficiently pull fine dust particles. If you’re looking for a cyclone dust collector, please drop us a line. KMS can special order cyclone collectors from a variety of manufacturers.
Ambient Air Filters
It’s not a bad idea to install an overhead ambient air filter to supplement your dust collection system. Overhead filters clean and circulate air through a series of pleated filter media and remove fine dust particles that would otherwise remain long after the sawing and sanding is done. “To improve airflow in the shop,” says Glasgow, “position your overhead filter at the edge of your shop and angle the exhaust so it hits the wall and creates turbulence. This helps keep the clean air moving.”
Remotes and Switches
Adding a remote control or an automated switch can improve your workflow, especially in a larger shop. But these upgrades are more than just time-savers. With a remote control, you are more likely to turn on the dust collection system, even when you are making only a few cuts. This means less dust in your lungs. With automated switches, your dust collector will activate whenever you use a connected tool. And after you power down your tool, the switch keeps the dust collector running for several seconds to remove residual dust from the air and your ductwork.
Whether your shop is large or small, proper dust collection will make it safer and cleaner, and while it might take time to plan and build an effective system, your shop is worth it—and so is your health. If you have any questions about dust collectors and accessories, give us a call, send us an email or stop by one of our nine locations. We’d love to help you find the best dust collection solution for your shop.
(If you really aren’t sure how to set up a dust collection system for your shop, think about consulting a professional mechanical engineer who specializes in dust control design.)
Check out our line of Magnum Industrial dust collectors in the slideshow below!