|Project by Aggie69||posted 12-18-2012 03:18 AM||19502 views||86 times favorited||25 comments|
I have a small workshop with several tools that generate a lot of dust and sawdust. I wanted to build a dust collection system that wouldn’t break the bank, was small and didn’t take up a lot of room, and could be built from off the shelf components from the local lumber yard.
I had an old 2 1/2 inch Sears Wet Dry Vacuum system that was great as a vacuum, but clogged up way too easily to use around dust and sawdust. I’d seen reviews of the Dust Deputy by Oneida. It’s an inexpensive ($40) cyclone separator for dust and sawdust. I bought one and tried it and it worked great! In a test, I picked up piles of sawdust that were deposited in the cyclone separator container leaving the vacuum filter completey clean This, connected between the old Sears Wet Dry Vac and the piping for my new dust collection system, became the work horse of the shop. Building it into a simple dust separator was very easy, using a 5 gallon bucket, a couple of pieces of 3/4 ” plywood cut into two circles (inside bucket diameter and 2” larger than the bucket diameter), six bolts, and a little silicone sealant.
I found very quickly that when a company gives you a dimension for something, say 2 1/2 inches, that’s really not the dimension you probably need. It may be the inside dimension, outside dimension, nominal dimension, dimension of the adapter on the hose or the inside or outside dimension of the hose itself!! Trying to understand what’s available on the market and what hose fits what adapter was a nightmare. My Wet Dry Vac had a hose adapter that was classed as 2 1/2 ” because of the outside diameter of the fitting on the hose. The hose itself had an ID of 2”. I decided to use 2” PVC from the local Lowes – Home Depot because it and it’s associated fittings were readily available and very inexpensive (~$6 for a 10 ft length). Plastic 2” conduit hangers were also inexpensive and readily available there as well. Since dust moving through plastic generates a tremendous static charge that will knock you on your keister, I devised a very simple static dissipation system. I used 2” foil tape (like that used in heating and air conditioning duct installation) and ran it along the length of the PVC pipe collection system. At each blast gate, I installed a #12 machine screw through the tape and into the PVC. These became clipping points to which I attached grounding wires from the various collection hoses. One of the screws became the attachment point between the foil system and the electrical ground of a 110V outlet.
There are a number of distributors that sell blast gates (the open/shutoff between individual tools and the dust collection system). Unfortunately, they don’t give you actual dimensions of the valve. A 2” valve doesn’t necessarily connect to 2” PVC (which is 2” ID). Rather than taking a chance (and probably being wrong), I decided to build my own valves where I knew they would be the right size. I built them out of 3/16 Masonite (hard board). I cut short pieces of 2” PVC pipe and glued them to the outside pieces of the blast valve body. This way they would fit directly into the 2” PVC TEE’s or elbows for each tool hookup. The blast valve shutoff slides are 3/16” Masonite also, sanded down a little to fit into the opening and slide smoothly.
For connection hoses I decided to use two sizes 2 1/2” and 1 1/4”. I ordered two 13 ft lengths of 2 1/2” hose from Sears (~$19 ea) thinking they would match up nicely with the old 2 1/2” hose from the Vac. —NOT—They don’t have the embedded wire coils in them like the old hose, they’re NOT right hand spiral wound (they’re concentric circles of plastic), and they’re not the same size as the old hose. I had purchased some 2 1/2” hose adapters through the internet. They fit the old hose perfectly, but were the wrong size for the new hose. What did work great however were 2” PVC FITTINGS. The new hose was a perfect interference fit into 2” PVC fittings (like a 2” PVC coupling which would then attach directly to the blast gate). At Lowes, they had some 1 1/4” flex hose that they sold by the foot. It was quite expensive at $2.68/ft. While getting ready to purchase several feet of it, I ran across the same size hose in black called well discharge hose. It was in a package 24 ft long, over by the well and septic system supplies, and only cost $10!. 1” PVC pipe fit into the hose very well as a connector only requiring a hose clamp to finish the connection. I used braided picture frame wire that I ran down the inside of each flexible hose. I brought the wire out at each end of the hose leaving several inches free. At each end I attached a small alligator clip clip that could be used to attach to the grounding bolt at the blast gate or to the tool itself. These supplied continuity for the static dissipation system.PVC Pipe Dimension Schedule 40 (Schedule 80 is same OD, but smaller ID’s)
Pipe Size (in) -OD (in) – ID(in)
- 3/4 ——- 1.050 ——- 0.824
- 1 ———- 1.315 ——- 1.049
- 1 1/4 —- 1.660 ——- 1.088
- 1 1/2 —- 1.900 ——- 1.610
- 2 ———- 2.375 ——- 2.067
- 2 1/2 —- 2.875 ——- 2.469
- 3 ———- 3.500 ——- 3.068
- 4 ———- 4.500 ——- 4.026
- 5 ———- 5.563 ——- 5.047
- 6 ———- 6.625 ——- 6.065
- 8 ———- 8.625 ——- 7.981