Dust collector Plumbing.......

[Andre Cormier]

Hi,

I have a HF DC and will be plumbing it shortly. The plan is 6" pvc pipe along the ceiling with 4" down to the tool. The DC will be direct vent outside with thien separator. Most of the setups I have seen are one long continuous trunk along the wall. For my setup, it would be better to have a 6x6x6 wye before the DC and have 2 trunks along the ceiling. Is there a reason why this would not be possible?

Merry Christmas!

[Dan Friedrichs]

Assuming you're using blast gates at each tool, no, there is no reason not to use 2 trunks. That will be fine.

That said...

If you're really only using 4" to each tool, you might as well just use 4" trunks. The smallest diameter determines the flow rate for the entire system, so even a short section of 4" pipe will result in a system that performs nearly the same as a system that entirely uses 4" pipe. For the best performance, run 6" all the way to the tool, not reducing at all for any reason.

[Mike Cruz]

For the most part, Dan's got it. I mean, if you are running 6" pipe for 40' and then go to a 4" pipe for the last 3', that would probably be better than running 4" the whole way (because of the reduction of flow due to the friction of 40' of 4" pipe verses the 6" pipe). But the bottom line, as Dan says, is that you are better off running the 6" pipe all the way to the machine. If you don't have a 6" port, make one. Or split the 6" into 2 4"ers at the machine and try to do one upper and one lower, or something like that. The splitting works well for TS's, BS's, and drill presses. One direct 6" port works well for planers and jointers.

[Dave MacArthur]

Same as both above. Don't run 4" drops. Run 6" drops, 6" main, and split your 6" drops to two 4" ports per tool, or a 6" port.

[Aaron Montgomery]

Agree. Run 6" to each tool if possible. I did this for my HFDC and it worked fine. That included changing the ports at several tools. It works better now that I've replaced the HFDC with an Oneida V-3000. (Though I also completely changed my duct runs)

[Leo Graywacz]

4" will restrict your flow to 350 cfm to that machine. If you have a DC that will pull more than that then by using smaller drops on each machine it will give you the opportunity to have more than one gate open. One of the benefits of having a smaller drop to the machine is getting a higher velocity in the duct that will help lift the chips straight up against gravity. I don't recommend going smaller that 5" on drops and if your port to the machine is smaller than that have a reducer right at the port to reduce losses.

5" will limit you to about 550 and 6" is about 785. If your machine doesn't require this amount of draw then you are just wasting CFM that can be used elsewhere in your system.

Here is a program from Bill Pentz's site to help you design your system. You will need Excel to use it.

http://www.billpentz.com/woodworking/cyclone/staticcalc.xls

[Andre Cormier]

Glad I posted this question.....

My shop is small so I need to have my tools semi mobile. There will probably be flex hose from the trunk down allowing me to orient the machines differently.

So far the only tool set up for dual 4" is the bandsaw. I was planning to have 2 6x6x4 wye's on the trunk and lead two 4" flex hose down to the saw. The trunk will be directly overhead so fairly short pieces of flex.

Is there a benefit to running a 6" down and then splitting that in 2 4" to the upper and lower port on the saw. There really would only be a difference of about 5' of 6" pipe vs two 4" pipes.

My Rigid Planer Seems to be doing fine with the 4" port. Will bringing a 6" to it be that much better?

Thanks

[eugene thomas]

i ran my dust collector system with 6" main line and each tool off main with 6x6x4 y's. i wish used y's with all 6" openings. then when want to go with bigger line to each tool not had to break apart the main line again to change out the y.. but i have feeling my dust collector system will be a project that will never get done. just keep improving or adding on as the tools keep coming.

[Chris Strizver]

My Rigid Planer Seems to be doing fine with the 4" port. Will bringing a 6" to it be that much better?You're thinking of it wrong. If you DC has a 6" port out, it actually needs at least a 6" opening somewhere along your system in order to pull enough air to maintain enough CFM to keep dust suspended in the airstream. So, even though your planer seems to do fine with a 4" port, if you reduce down to 4" pipe X number of feet before the tool you'll be restricting airflow. Your DC simply can't suck the same volume of air. Once the air hits the 4"->6" transition, it slows down considerably with all the extra space.

Now, it may just be that your DC is powerful enough to pull enough air to collect the chips and keep them suspended even with a reduction to 4" pipe. But then you're cheating yourself of fine dust collection potential. And fine dust collection --the stuff you can't see and the stuff that kills you-- comes at a premium. Best to not cheat yourself of it.

Of course, the planer doesn't make a whole lotta fine dust. YMMV

[Dan Friedrichs]

Is there a benefit to running a 6" down and then splitting that in 2 4" to the upper and lower port on the saw. There really would only be a difference of about 5' of 6" pipe vs two 4" pipes.

It would probably be about the same either way. I'd caution you against using much flex pipe, though - if you must use it, keep the pieces short and try to find the stuff that has a relatively smooth inside wall (ie - the wire is on the OUTSIDE).



My Rigid Planer Seems to be doing fine with the 4" port. Will bringing a 6" to it be that much better?



Planers don't really generate fine dust, so as long as you're getting all the chips (or whatever percent of them that you're happy to have collected), it's probably fine. Also, it would be pretty hard to hack a larger dust port into most planers (unlike, say, a table saw, where it would be relatively easy to enlarge the dust port). So if you're happy with this, I wouldn't worry about it.

Unlike Chris, I'm not very concerned about the dust settling in the duct work. If you are concerned, just put a 6" gate at the very far end of each trunk, and open it for a few seconds every so often. That will get the full amount of air running through the duct and clean it out. But I have several 4" ports connected to 6" ducts, and have never noticed any accumulation.

[Andre Cormier]

After reading your opinions and other searches on the net I think I will plumb 6" to every tool. I was hesitant to use 6" because of the availability and cost of the flex pipe. but I found some at Penn State at a decent price 25' for 100$. I will try an limit the length of flex hose to less than 5' per tool.

http://www.pennstateind.com/store/N-CVD-0625.html
Has anyone used this hose, any good?

Here is what the system will be:

- New HF DC with thien baffle.
- Direct vent outside, no bag.
- 6" PVC trunk, 6" down to tool
- I will try and mod the tools to accept 6" or 2x4"
- if 4" is as big as it will go, a long sweep reducer right at the tool 6" down to 4"
- One tool at a time with the use of use blast gates

Have I got my DC Planned out correctly? Any other suggestions to the settup?


Another thing that I have added to my shop that has been great is a large fan mounted through the wall with aluminum louvers on the oustide. It's capable of moving 1600 CFM's of free air and in "theory" can replace the air in my small shop in 2 minutes. I live in Florida so heat loss is not a problem, it actually cools nicely in the summer. Coupled with a properly plumbed DC I should be relatively dust free.....I hope.

[Mike Cruz]

Sounds like you have a good plan there. Yeah, venting outside's biggest issue is heat/cold air loss. But if you are okay with the outside air temp, you're lucky. That said, it is hard to control your humidy, though. Something to think about.

The only thing I might add to your plan above is a theory of mine... And take it for what it is, a theory. Since 6" flex pipe has more resistance than 6" PVC, I've wondered why not use 7" flex pipe with 6" PVC? I would imagine that the drag coefficient and air handling capacity of 7" flex is similar to 6" PVC. I would still put 6" ports on your machines. I came up with this hair brained idea when after stretching the 6" flex pipe over 6" PVC piping, I looked at it and realized that the 6" flex pipe looks a little smaller than the PVC, and I probably should have ordered the 7". BTW, if you, or anyone else, is wondering HOW I got the 6" flex pipe over the 6" PVC, I cut out about the last 2-3 inches of wire (the amount of flex pipe that you need to go over the PVC) in the flex pipe and then used will power, strength, and determination to MAKE it get on the PVC. It ain't easy, but she'll go...

[Dave MacArthur]

Andre--
Your new plan sounds quite good! All the best options, can't think of anything to suggest. Now good luck on the build!

Oh, one last thing, there are tons of threads here on getting 6" pipe for DCs in the right format and price, and most folks report using the sewer DWV thin-walled pipe (it has some number but I forget it) as the cheapest and best option for fittings. I think you should do a search here a bit more looking in the workshops forum for DWV pipe, sewer pipe, DC pipe etc. and see what folks are saying, they've totally cracked this piping nut many times. And I'm about 99% certain that local procurement of the pipe is the way to go.

Just re-read you post and it looks like maybe you were only talking about getting the flex hose at Penn. In any case, there's a thread here for "best sources for DC fittings" and what all goes together nicely without trial and error.

[Dan Friedrichs]

That sounds great, Andre. You should be able to get very good performance out of that system, for not very much money.

The PVC pipe that Dave is talking about is ASTM D2729.