Piping new-to-me DC

[David L Morse]

Does 6" flex hose fit over the OD of 6" PVC?

Typically no, but most will fit inside a 6" coupling if you cut some threads for the wire spiral.

Threads.jpg

[Ron Selzer]

Does 5" plastic pipe even exist? I have found a bunch of 5" abs gates and flex hose, but no pipe or other fittings.

5" plastic pipe is out there but the price is way up there, cheaper to buy Nordfab
5" x 5' pvc sch 40 $188.39 pvcfittingsonlinedotcom
home depot has some fittings listed online but no pipe

[Alex Zeller]

You may find 5" PVC conduit at a local electrical supplier cheaper than 5" pvc pipe.

[Michael Schuch]

I'd go next size higher, with the qualifier that I use metal duct which is available in 1" increments. My 2hp Oneida system has a 7" port and I have 7" duct out to the major branch for the main and 6" from there. I'd settle for some slight settling over restricting max CFM...but that's a personal point of view.

I have been struggling over having a larger main line than the branches. I have been thinking about exactly what you have with a 7" main line and 6" branches. If I only use 1 tool at a time and only have one gate open at a time is there any advantage to have the 7" main line? A 7" main line or bigger makes sense to me if I had more than one gate open at a time but being a one man shop it seems like a 6" main line would be sufficient??? I certainly wouldn't want to go down to a smaller duct diameter. Most of my machines only have 4" dust ports except my new to me table saw has a 6" port.

I have a used 3hp 3ph blower on a fair sized cyclone out of a professional wood working shop that closed. They had the most cobbled together ducting I have ever seen with 3 or 4 different types of pipe including metal, HVAC duct and different sizes and different wall thicknesses of PVC.

[Ole Anderson]

Michael, if you have longer horizontal runs going up to a 7" main definitely has benefits, mainly less friction losses, therefore more airflow. 800 cfm airflow on a single machine is not out of the question. I pull that much or more with my 2 hp Oneida SDG (same as Jim) with my TS, 5" bottom, 3" top connection. 6" pipe size on your vertical runs would be recommended to increase velocity a bit to be able to pull small offcuts along with the dust and chips. 800 cfm in a 7" duct will get you almost 3000 fpm velocity, the same flow in a 6" pipe will get you a bit over 4000 fpm velocity but at the cost of more friction losses..