Dust collection - would you go 4" or 6" in this setup?

[Alden Peterson]

I am redoing my absolutely awful dust collection setup. Right now I have a setup with (picture at bottom):

* Oneida 4/5 super dust deputy
* Shop Fox 1.5hp dust collector
* wynn filter

I'm fixing this because this system is suuuuper bad downstream as I've consistently just hacked it every time I've needed it changed. And now it's a terribad setup, so I need to redo it - plus some of my tools stopped reaching.

What I don't know is whether 4" vs 6" pipe here matters if I have a relatively small DC. I don't have 240v for the DC either, so it's going to be limited to the roughly 1.5hp.

If I do 6, I'd have to get a larger dust deputy (this one only has 5" max). But I'd be able to do 6" everywhere else. I think the longest run is about 25 feet from here too.

With a relatively small DC and pushing through the Wynn filter does the 4" vs 6" even matter meaningfully? I'm not opposed to doing 6" main line, but I would have to replace the dust deputy, which is rather pricy. But I am redoing the whole thing so maybe that's worth it still?

Or should I just put 5"->6" adapters on the dust deputy.

What would you all do?

Here's the current setup - https://imgur.com/giNSjKG

[Ron Selzer]

I would go with a 5" 30 gauge steel main line, try to minimize your bends, use 2 adj. 90 set to 45 to make a 90 bend, etc. reduce to 4" when going to a tool. Minimize flex hose as much as you possibly can. You have a small system so don't choke it off with 4", 6" you won't be able to maintain velocity in the duct.
Ron

[Jim Becker]

5" is optimal for that setup and yes, that means using metal

[Alden Peterson]

Sanity checking, if I go 5" then I'll have to buy:

* 6" to 5" reducer for dust collector inlet
* 5" flex hose, from cyclone to DC
* 5" metal pieces for the run along the wall
* 5" 45s to get from cyclone to wall (I think 2x 45 degree pieces would work here)
* 5" with 5" out/4" out "Y" pieces to put along the wall. The 5" continues the run and I put a 4" blast gate on there attached to 4" flex hose to the machines
* necessary 5" metal tubing
* some sort of tape (presumably)? Do you also caulk or just tape/screw with self tapping?

Where do you all recommend buying things? And do they make that 5x5x4 or whatever you'd call the Y piece like that?

[Jim Becker]

Blastgate Company is a good source. If the runs are all short you might be ok with 6" plastic, but with that blower, a big 6" network might not perform well. My G700 kicks hiney and while the frst 20' or so is 6", the entire rest of the network is 5" and the performance is really good

[Alden Peterson]

Blastgate Company is a good source. If the runs are all short you might be ok with 6" plastic, but with that blower, a big 6" network might not perform well. My G700 kicks hiney and while the frst 20' or so is 6", the entire rest of the network is 5" and the performance is really good

One of the perks of having a small shop - less needed

I think I'll go with 5" - from what I can tell the 6" plastic connectors are significantly more expensive than the 4" ones and so the price point becomes closer.

Now I just have to figure out how much to get if I get from Blastgate company. All these things together are going to be a lot more $ than I anticipated though, pretty much regardless of what size I choose between 5" and 6" -- the only real cost effective option seems to be 4" but I think my total is still going to be not super long. Unless instead of making the run to my jointer just across the floor I make it go up and over the garage ceiling hah.

[Bill Dufour]

I read somewhere that two 45's inline are more restriction then one 90 semi sweep elbow. This is due to longer length and more bumps inside due to multiple joints. Not sure if I believe it or not.
Bill D

[Kris Cook]

Sanity checking, if I go 5" then I'll have to buy:

* 6" to 5" reducer for dust collector inlet
* 5" flex hose, from cyclone to DC
* 5" metal pieces for the run along the wall
* 5" 45s to get from cyclone to wall (I think 2x 45 degree pieces would work here)
* 5" with 5" out/4" out "Y" pieces to put along the wall. The 5" continues the run and I put a 4" blast gate on there attached to 4" flex hose to the machines
* necessary 5" metal tubing
* some sort of tape (presumably)? Do you also caulk or just tape/screw with self tapping?

Where do you all recommend buying things? And do they make that 5x5x4 or whatever you'd call the Y piece like that?

I used self-tappers and then wrapped the joints with aluminized tape. That has worked well. I was able to buy spiral metal pipe locally at a wholesaler. Do you know anyone that is in the HVAC or similar business?

[Curt Harms]

I have a somewhat similar setup - "2 h.p." DC with 12" blower. I'm led to believe that the 12" blower is more important than the 2 h.p. Wynn filter with Thien baffle in the D.C. 6" S&D PVC seems to work fine, the air velocity is such that material doesn't settle out. It is only about a 15 foot run which I'm sure helps. The machine came with a 6" inlet and plastic 6" to 2 4" fitting. I removed the 2 4" fitting and 6" pipe fits pretty well. I did a few wraps of duct tape on the metal inlet for a more air tight fit. I keep one blast gate open at a time. I did try two gates open at one time just to see and the air velocity did decrease though not as much as I expected. I fabricated my own blast gates.

[Alden Peterson]

I have a somewhat similar setup - "2 h.p." DC with 12" blower. I'm led to believe that the 12" blower is more important than the 2 h.p. Wynn filter with Thien baffle in the D.C. 6" S&D PVC seems to work fine, the air velocity is such that material doesn't settle out. It is only about a 15 foot run which I'm sure helps. The machine came with a 6" inlet and plastic 6" to 2 4" fitting. I removed the 2 4" fitting and 6" pipe fits pretty well. I did a few wraps of duct tape on the metal inlet for a more air tight fit. I keep one blast gate open at a time. I did try two gates open at one time just to see and the air velocity did decrease though not as much as I expected. I fabricated my own blast gates.

The biggest question I have is if I do 6" pipe everywhere if my 5" through the Super Dust Deputy is going to be a limit to make it kinda pointless.

[Rich Aldrich]

The key to the duct size is keeping the air velocity above 3500 Feet per minute. Velocities below will let sawdust drop out and you will have build up in the ducting. We target 5000 - 5500 FPM in our systems at the saw mill to prevent build up. If the velocity is too high, the pressure drop gets to high and reduces the total CFM. Best to size the duct for the air speed.

[glenn bradley]

I read somewhere that two 45's inline are more restriction then one 90 semi sweep elbow. This is due to longer length and more bumps inside due to multiple joints. Not sure if I believe it or not.
Bill D

A long sweep is optimal. The price versus the benefit tipped me to a pair of 45's. Dust collection for home shop folks is a series of compromises. Spend on the big winners and save on the small stuff. Just watch that you don't have enough small stuff to equal a big impact item .

To the OP; For what metal ducting costs (it's not really the pipe, it's the fittings, suspension system, and snap collars that add up) I would hesitate to spend a lot on your current system. I would add up what the "next band aid" is going to cost and compare it to a purpose built cyclone system. It won't be a push by any means but I would want to know how much more money I am throwing at a system I already don't like before I took the step. Not trying to be brutal, just trying to help.

[Alden Peterson]

A long sweep is optimal. The price versus the benefit tipped me to a pair of 45's. Dust collection for home shop folks is a series of compromises. Spend on the big winners and save on the small stuff. Just watch that you don't have enough small stuff to equal a big impact item .

To the OP; For what metal ducting costs (it's not really the pipe, it's the fittings, suspension system, and snap collars that add up) I would hesitate to spend a lot on your current system. I would add up what the "next band aid" is going to cost and compare it to a purpose built cyclone system. It won't be a push by any means but I would want to know how much more money I am throwing at a system I already don't like before I took the step. Not trying to be brutal, just trying to help.

Honestly my existing setup works... surprisingly ok right now. I'm shocked how well it works given how hacky it is. But I do have to change things given where I moved tools. Which has me considering doing it right, or at least, less bad

And yeah, pricing out a relatively small 5" system is starting to get to be quite a few hundred dollars.... I'm not sure if I should just do 4" and call it good enough (-:

What do you mean by "purpose built cyclone" system?

[glenn bradley]

Honestly my existing setup works... surprisingly ok right now. I'm shocked how well it works given how hacky it is. But I do have to change things given where I moved tools. Which has me considering doing it right, or at least, less bad

And yeah, pricing out a relatively small 5" system is starting to get to be quite a few hundred dollars.... I'm not sure if I should just do 4" and call it good enough (-:

What do you mean by "purpose built cyclone" system?

I misunderstood. I thought you disliked the performance . . . my bad . A re-build / retrofit could probably be done for much less that new .

By "purpose built" I mean a system designed to expect the hit on airflow introduced by the cyclone. The horsepower, fan size, fan curve, etc. are all built expecting a certain set of operational parameters. When we put a separator ahead of or behind the blower we change that and there is not really a way to "adjust" the blower's design.

That being said, I started with a Shop Vac and a 5 gallon bucket separator. Upgraded to a 4" bagger, added a separator. Upgraded to a cyclone with a 6" main and 4" drops and am now at a 6" main with 6" drops on all but a couple of machines. So, I have a good range of experience as far as a home shop, weekend warrior goes. That doesn't make me right . Dust collection is, like our shops, a journey .

I will say that moving from a 4" port to a 6" on things like the tablesaw and jointer improved things substantially. I am really milking my 2HP cyclone for all it's worth. Although I built out the area in anticipation of upgrading to a 5HP cyclone the 2HP is doing a decent job so I am holding off on that expense . . . At my age you really start to think about whether things will last for at least 10 years. After that I probably won't care much

[Rob Luter]

The key to the duct size is keeping the air velocity above 3500 Feet per minute. Velocities below will let sawdust drop out and you will have build up in the ducting. We target 5000 - 5500 FPM in our systems at the saw mill to prevent build up. If the velocity is too high, the pressure drop gets to high and reduces the total CFM. Best to size the duct for the air speed.

^^ This ^^