Dust Collection 101

09 Sep.,2024

 

Dust Collection 101

As a woodworker, keeping dust out of your lungs is one of the best things you can do for your health, along with always wearing eye, ear, and respiratory protection in the shop, and making sure you have the same number of fingers at the end of the day as at the beginning. And unlike the treadmill in your basement, collecting dust is something best done intentionally and proactively. In this article, we'll go through the various options for dust collection, explain what you need to know about pressure and flow rate, explore best practices, and try to keep sarcastic wisecracking to an appropriate minimum. WEN has an extensive lineup of air filtration systems, dust collectors, vacuums, accessories, hoses, and more to meet all your dust collection needs.

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Dust collection categories

Broadly speaking, you can break dust collection methods down into 3 categories: 

  • Point-source: as the name implies, this is collecting dust at its source. Think of a wet-dry vacuum or dust collector hooked up to a tool directly, such as a circular saw or hand sander. This is the method most often used with small and/or handheld tools.
  • Central: this method makes use of a central dust collector and a series of ducts or tubing, connectors, and/or blast gates combined in a network. This network hooks up to multiple (usually stationary) shop tools such as sanders, band saws, table saws, and more.
  • Ambient: best used as a supplement to either point-source or central dust collection, this method uses a device such as an air-filtration system to scrub any dust from the air that was missed at the initial collection point, and is important for keeping air quality high and particulate concentration low.

A diagram showing the different types of dust collection.

Before we dive into a bit more detail, it's important to note that even if you have a great dust-collection system set up, it's always a good idea to wear proper NIOSH-appoved respiratory protection as an added layer of defense when dealing with wood dust.

Point-source dust collection

Collecting dust at its source is one of the keys to effective dust management. The point-source method offers maximum versatility and portability. Usually, this method will involve one dust collector (or wet/dry vacuum) attached to one other tool at a time. When you move to the next tool, you disconnect the collector from the first tool and connect it to the second. Simple, right? 

This method is often the least expensive and most modular, especially for those just beginning their woodworking journeys, or for anyone whose shop space is limited. However, it does involve a little more hassle than central dust collection - disconnecting the collector from each tool and reconnecting it can be a bit of a pain if your project requires many different types of tools to bring it to life.

Central dust collection

The central collection method is best used by those who have large shops, or advanced / professional woodworkers. It requires more resources and time initially to set up a duct network, and obviously, the more machines it will connect to, the more time, effort, and money it will take to set up. 

Generally, a central setup consists of: 

  • A central dust collector. It's often physically positioned centrally in the shop (or as close to centrally as possible) to minimize the distance between the collector and the furthest machines. This minimizes pressure loss (more on that later). This dust collector is almost always a dedicated dust collector, not a wet/dry vacuum, for reasons we'll discuss later.
  • The machines in your shop (duh). 
  • A ducting network. This network, in turn, consists of: 
    • Rigid or flexible ducts that connect to each machine and the dust collector. Most permanent setups use 4-inch to 6-inch diameter rigid tubing, which is more efficient than flexible hoses.
    • Blast gates to direct air flow within the network. Generally, they should be positioned as close to the collector as possible to maximize efficiency.
    • Connectors, cuffs, and fittings to connect the various parts of the network together. They come in all sorts of shapes and sizes.

If you have a small or medium-sized shop, and only need to connect to one or two machines, you probably don't need a large network of rigid tubing. You can likely get by just fine with a couple of blast gates, flexible hoses, and connectors.

The WEN DC (left) and DC (right) dust collectors are great for use as mobile point-source dust collectors, or can be mounted on the wall for use as central dust collectors in small to medium shops.

Keep in mind that central dust collection may require a large dust collector. Large dust collectors require large motors. Large motors require large electrical circuits. Some 120-volt dust collectors require a 20-amp or 25-amp circuit to run properly. Some dust collectors may require a 240-volt circuit, so make sure that your shop is properly wired to supply the dust collector (as well as the other machines in your shop, which will be running simultaneously). If it's not, bring in a professional electrician to help get your shop shipshape.

The WEN DC -CFM dust collector has two 4-inch inlets for easy connection to larger networks.

Once the initial setup is done, there's very little adjustment required. Simply turn on the dust collector, adjust the blast gate network to direct airflow from the tool(s) you plan to use, and get to work.

Ambient dust collection

Whether using a point-source method or central method, ambient dust collection is a great complementary option. It will not replace either of those methods, and is intended to help circulate and clear the air in your shop, not to collect dust from a tool or get it off your workbench. Most ambient dust collection is done using an air filtration system, often one suspended from the ceiling for maximum airflow. The system draws air into the housing through its filters, which capture any airborne dust, then exhausts the clean air into the shop. Look for a system capable of cycling the air in your shop several times per hour.

The WEN remote-controlled air filtration system is a great entry-level option for small to medium shops, garages, and more.

WEN offers several air filtration systems for various shop sizes; for more information, check out our helpful guide to choosing an air filtration system.

Pressure and flow rate

For more information, please visit Dust Proof Motor.

Let's shift gears and discuss a bit about the differences and relationships between pressure and flow rate. This is an essential concept to understand when selecting a dust-collection tool, so travel back to high-school physics class with us for a moment.

Pressure is force distributed over an area. In terms of dust collection, it's the "muscle" behind air movement. It's often expressed in pounds per square inch (PSI), kilopascals (kPa), or inches of water column (inWC or WC). If you prefer an electrical analogy, it's like the voltage in a circuit. When there is a pressure difference between two points in space, air flows from the area of higher pressure to the area of lower pressure. Higher pressure means more muscle, if you will.

Speaking of air flowing, the flow rate is the amount (volume) of air that moves through a given area in a certain period of time. It's often expressed in cubic feet per minute (CFM) or cubic meters per minute (CMM or m3/min). Dust collectors are often rated by CFM. Going back to the electrical analogy, it's like the current flow in a circuit. Higher CFM ratings mean more flow.

What does this mean, practically? Good question. Two things:

1. Pressure loss in a network

If you're setting up a central dust collection network, you will lose some pressure due to resistance in the system. As rules of thumb, a longer network will suffer more losses than a shorter one, and a more-complex network will suffer more losses than a simpler one. The goal is, of course, to minimize losses. To do so:

  • Use rigid tubing if setting up a large, permanent network. For semi-permanent connections to a couple of tools, flexible hoses will suffice. Flexible hoses cause approximately 5 times the pressure loss per linear foot as rigid tubing, depending on the diameter, flow rate, and construction. If using flexible hoses, stretch them as much as possible to minimize losses.
  • Keep connections as short as you can. Long lengths of tube cause more losses than shorter lengths, even in rigid tubing.
  • Avoid 90-degree turns if possible. Every 90-degree elbow causes a pressure loss equivalent to 5 to 10 feet of rigid tubing, again depending on the diameter, flow rate, etc. 45-degree turns or wyes cause about half that loss.
  • Make sure your connections are tight. Loose connections invite leakage. Use hose clamps at each connection point. If you're using flexible tubing, make sure there are no punctures or tears. 

The exact numbers and calculations are a topic for another time. Keep in mind that larger-diameter ducting generally suffers less loss than smaller-diameter ducting, but is bulkier, heavier, and more expensive. If you lose too much pressure in the system, you will not collect any dust, or will collect very little.

2. Air power

Combining pressure and flow rate gives power. It's important to understand that two different machines can offer the same amount of air-moving power, but do so in two different ways. Maybe one has high pressure and low flow rates, and the other has lower pressure but higher flow rates. One will be suitable for some tasks, one for other tasks. Many vacuums' power levels are advertised as being a certain number of airwatts, which is a measure of power (both pressure and flow rate, related by a mathematical constant). 

The WEN 20V handheld vacuum has a maximum power of 94 airwatts, and is a powerful, portable part of the WEN 20V lithium-ion cordless power tool system.

Another practical example of the difference here can be seen when putting wet/dry vacuums and dust collectors head to head.

Wet/dry vacuums versus dust collectors

As a general rule of thumb, wet/dry vacuums offer higher pressure and lower flow rates. Dust collectors offer lower pressure but higher flow rates. 

Wet/dry vacuums are often used to clean up general shop debris, wood chips, small pieces of concrete, and other miscellaneous construction detritus. Their higher pressure allows them to suck up heavier debris than dust collectors can, but they don't have very high flow rates, and are usually connected to flexible hoses. They do their best work when used as point-source collectors. 

The WEN VC and VC wet/dry shop vacuums are ideal for cleaning up all sorts of messes at home or on the job site, and work great as point-source dust collectors thanks to their included HEPA filters.

Dedicated dust collectors, on the other hand, tend to have much higher flow rates than shop vacuums, meaning they are not as good at picking up heavy debris, but are very good at moving lots of small debris (i.e. sawdust). As we mentioned earlier, this is why wet/dry vacuums are almost never used as central dust collectors. 

For general point-source collection, it's important to choose a tool that will work well for your needs. A dedicated dust collector may not perform as well as a shop vacuum when connected to woodworking machinery that produces large chips (planers, jointers, etc.), since those chips are heavier than fine sawdust. However, when used with machines that produce fine sawdust (sanders, band saws, table saws, etc.), dust collectors excel. 

Dust collection: best practices

If you just need the basics, here they are: 

  • Wear NIOSH-approved respiratory protection. 
  • Use point-source dust collection (whether a wet/dry vacuum or dedicated dust collector) whenever possible. If you have a central dust collection setup, use it as well.
  • Ambient dust collection machines, like air filtration systems, are a helpful supplement to point-source and central dust collection. 
  • If you have a machine that produces large chips, a wet/dry vacuum may perform better than a dust collector. If your machine produces fine sawdust, a dust collector will excel. 

Your lungs will thank you, and considering you're not tracking dust all over the house, so will your family.

Conclusion

Thanks for reading! If you have any questions, or need help deciding which WEN dust-management machine is right for you, please give us a call at 1-847-429- (M &#; F, 8 &#; 5 CST), or drop us a message here to talk to our friendly and knowledgeable technical support team.

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