Dust Collection For The Workshop

 

 This article is about dust collection. There are a lot of articles and discussions on this topic available via the Internet. I think I've read them all. You won't find anything new here, but perhaps it will save you a little time sorting your way through the information.

I'll read this later! Take me directly to the pictures on how you put stuff together

The saga begins....

Dust collection is about two distinct things. Keeping the shop clean, and keeping the shop air healthy. Usually, people are after the first thing when they start looking at dust collection. It's the second thing that causes all the problems.

Woodworking machines such as a tablesaw or planer produce chips, sawdust and shavings that cause a great big mess. In addition, they also produce a lot of fine dust that dirties the place up a little, but doesn't cause it to look like a disaster area. Most people try to keep the sawdust under control via a shopvac, which works fine. Shopvacs generate a lot of static pressure ("suction"), which easily takes care of all those chips and shavings. Still, vaccuuming up sawdust is suspicously like housework, it would be much better if all that stuff ended up in a trashcan rather than on the floor.

Fortunately, most woodworking machines have some sort of connection for dust collection. You attach a hose to the tool, run the hose to your dust collection machine or shopvac, and most of the sawdust ends up safely in a bag or can. Moving a hose from tool to tool can be cumbersome, something you can avoid by running some ductwork to each tool. Problem solved!

Of course, that would be too easy.

The Bill Pentz effect

If you do any kind of research on Dust Collection on the Internet, you'll come across Bill Pentz' web site. Bill is a woodworker who developed severe allergies to wood dust. Despite the best dust collection equipment, he couldn't go back into the shop because of health issues. His web site has a lot of good information, but it will take you the better part of a weekend to read. It is also very depressing. Most people are ready to throw in the towel after reading all the information, because they can't or don't want to spend so much money on dust collection.

I suggest you take Bill's information at face value. I don't like his shock and awe style, but I can understand why he feels so passionate about the subject. Some people disagree with Bill's conclusions, but I have not seen his facts disputed anywhere. You'll have to determine for yourself how much of a risk you consider the dust to be.

According to Bill. you need to move roughly twice the amount of air people previously thought was required. To move that kind of air, 4" pipes and hoses wouldn't cut it, you'd need at least 6". Of course, 4" is the industry standard. Nearly all woodworking tools (table saws, jointers, planers etc.) have 4" dust ports. Many people don't like the idea of having to saw holes into their precious machines to enlarge the port. Also, pipes, hoses, duct fittings and blast gates with a 6" diameter are three to four times as expensive as those with a 4" diameter. Finally, to generate enough static pressure ("suction") for such a big pipe, you need a big impeller and a big motor. All this adds up to lots of money and effort. My estimate is around $2,500.

It's natural to blame the messenger for bad news. It's no wonder that there are some very bitter fights on the various woodworking forums on this topic.  

Why so much air?

The problem is the fine dust. A shop vac is great for cleaning up wood chips, but it doesn't have much of an effect on the fine dust particles. These sort of swirl around, oblivious to the whining efforts of the shop vac. Even a real dust collection machine with a 1.5HP motor doesn't have much of an effect. To capture the fine dust, you need to move a large volume of air. And to move that amount of air, you need big pipes, with a diameter of 6" or more. That's big, a lot bigger than the hose on a shopvac.
A little math for comparison: The area of a circle is PI * r2. A shopvac uses a 2 1/2" diameter hose, so the radius is 1.25. The area is therefore PI * (1.25)2 = 4.9". For a dust collection hose with a 6" diameter, that's PI * (3)2 = 28.3". That's more than five times the air! If you were to take a 6" hose and put it on the same shopvac, you'd move a lot of air of course but very slowly. The static pressure ("suction") would drop to almost nothing, a shopvac simply isn't built for that.

The options

There are several options. The first is to abandon the idea of dust collection altogether, and use a broom and maybe a shopvac to clean up now and then. The second option is to create a basic dust collection ("chip collection") setup that will keep the shop clean but won't capture much of the fine dust. The third option is to suck it up (pun intended), spend the money, and build yourself a real dust collection system.

Keep in mind that the dust collection system is only part of the solution. You still need a shopvac with a good HEPA filter, wear a respirator and run an air cleaner. If you can work outside, or open doors/ windows, so much the better! Also, there is little point in getting every bit of dust out of your planer if you neglect to install an overhead guard (with DC) over your table saw blade. Or use a sander without hooking it up to a shopvac.


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