I’m looking for suggestions from anyone who has built their own dust collection system using PVC pipe and the corresponding fittings. I have a craftsman 5.0 HP wet/dry vac that I’m looking to use for the vacuum. I also am looking to invest in a Dust Deputy and install it on my own bucket. My question is what diameter PVC would be best for my vacuum 1 1/2" or 2" piping and corresponding Ball Valves.
Any ideas and help is appreciated.
I did what you are doing few months ago and personally I’m bit disappointing with Dust Deputy setup. While its working fine I’m very much dislike running vac for hours with no end. I went with 2-1/2 pipe all around with following gates:
Sadly I had to mod them a bit as they leaked some air.
Got section of this pipe for looks mostly:
Few intersections like this:
and bunch of this all over the place:
Sadly I cringe every time I I see this unit go for sale at 169$
Here are some thoughts to help you with your squirrel-cage idea. Squirrel-cage fans are ideal for moving a lot of air, or CFM, through a duct system having little restriction to flow. Vacuum fans may move less air, but they have the ability to generate a high amount of suction, or “inches of lift”. The combination of flow and suction is what must be considered when designing a vacuum for a given purpose, i.e. separating dust. Here’s a formula for “Air Watts” you might want to research: (Air Flow * Vacuum)/8.5 = Air Watts. Again, Air flow is in Cubic Feet per Minute (CFM) and suction, or Vacuum, is in Inches of Water Lift. Since vacuum is calculated at the working end of the hose, one must also consider the amount of restriction to air flow caused by reducing the size of the hose or duct the air is flowing through. For example, going from a 4" duct to a 2-1/2" hose results in a 37% reduction in the cross-section that the air must flow through. If the CFM is to remain unchanged, the amount of suction would mathematically have to increase substantially in order to maintain air flow.
Leakage around the edge of a squirrel cage fan, cavitation, and horsepower of the fan motor are other important considerations that cannot be ignored in your plans. Since squirrel cage fans are not designed to generate a lot of suction, or inches of lift, you should expect a considerable drop in suction at the working end of your vacuum hose by the time you shrink the cross-section of the squirrel cage inlet down to work with a 2-1/2" hose connection. Now, you must also consider the amount of flow restriction caused by the cyclone!
Bottom line is this: a squirrel cage fan as a vacuum source for a cyclonic separator is not going to result in a device that is particularly good at picking up sawdust. The amount of airflow at the working end of the pick-up hose would be so wimpy that it would not begin to keep up with the amount of dust you will generate with your cutting, planing, milling, or sanding operations.
Great choice of central vac system! Same rules apply if you want to use a bucket lid separator near the point of collection. I’ve got a 1250 CFM system, but the fine separation is not on par with the smaller bucket top devices. Good luck!