DC Ducting -- How far is too far ?

[ssmith1627]

Just a week ago picked up the HF 2HP DC. I've read a lot of the threads here about DC ducting but now that I actually have one, a whole lot more questions come to mind !

My inital idea was to implement something like this drawing on the Rockler site:

http://images.rockler.com/rockler/images/68665-lg.jpg

The ducting up to the ceiling, across, and back down to my table saw from the DC would be about 20 feet. The ducting to the floor sweep would be about 15 feet. And the ducting to where I now have the router table would be 28 feet ! Is it ridiculous to think I'm going to get enough suction that far away ? I wanted to get some feedback before I started actually connecting these things.

Will I be better off running 5" hose / piping ? Especially for these distances -- will that help ?

Thanks guys -- as always -- I appreciate the advice !

Steve

[daniel1954]

Dc

I have simular distances with my 1hp DC. I used 4 inch PVC for mine. I don't think you will have any issues as long as you close off all the areas you are not using. Even with my 1hp I can usually have 2 open at any one time so you should be good to go. Of course, just like shop size, you can never have too much dust collector.

[LCHIEN]

Going thru Bill Pentz's site is laborious but educational.
There you learn that your DC ducting is all a compromise.
Too large a dia and the air velocity is too slow to keep the particles suspended.
Too small and the friction resistance to flow overwhelms and the air flow falls off and the velocity suffers again.

Reading his tables I came to the conclusion that 6" was too big and 4" too small for my HF 2HP DC, 5" would be just right (said goldilocks), but, that stuff is hard to find.

The tables will give the approximate head loss from length and fittings of different diameters

I have yet to permanently plumb my shop, so take my take with a grain of salt!

Maybe 4" will work OK. Maybe 6" will work OK if there are not too long a vertical run.

[Popeye]

I used 4" thinwall pvc pipe run in the overhead down one side of the shop with a crossover for the RAS, jointer, planner. This is the longest run and is about 33' horizontal and another 14' in vertical drops. The biggest chip makers are the planner and jointer and it pulls all of it to the 55 gallon seperator. All friction fit (some screws to hold joints) HF DC, home made adaptors. Pat

[Tom Miller]

As long as you're using smooth-wall piping (e.g. sewer&drain pvc), I wouldn't hesitate to run a 30'+ line. That'd still be less resistance than 10' of flex hose.

You really want to minimize the flex.

If you can get 5", that might be a sweet spot, as long as you maintain decent air speed throughout. (But, the only reasonable source of 5" would be HVAC ducting.) Where you can run into trouble is if/when you choke down at the tool. You could end up with too low air speed in the larger lines.

Regards,
Tom

[ssmith1627]

Flex hose only seems attractive because you can get it in clear -- would be nice for those long runs up at the ceiling to know where a problem might be.

Noted the point about the solid wall stuff -- that certainly makes sense. What about flex for just the drops to each machine ?

Thanks for all the messages guys. It's great to knock this stuff around with you all when I'm tackling something new.

Steve

[Tom Miller]

...What about flex for just the drops to each machine ?

I only do flex for the last few feet of the drop that absolutely need to be able to flex. Treat every foot of this stuff like the plague.

Regards,
Tom

[JR]

Noted the point about the solid wall stuff -- that certainly makes sense. What about flex for just the drops to each machine ?

That's the way I do it. I believe you should do your best to optimize performance - within practical limits. For DC systems that means running solid pipe as far as you can. After that, wherever that is, you've reached the point where flex is required.

BTW - I've found that a standard 4" blast gate fits nicely into the black 4" PVC pipe and also into 4" flex. So the junction between the solid pipe and the flex is a good spot for a blast gate.

I guess my runs of solid pipe are about 12'-15' linear feet each (2 runs), plus rise and fall. The jointer, planer and bandsaw are at the end of the longer run and seem to get serviced just fine by my HF 2HP DC.

I just put on the Wynn .5micron filter last night and there seems to be loads of flow now. Those pleated filters, with their increase surface area, really improve flow. If you think your system might be on the edge of acceptable performance, a filter upgrade would help. You really need it anyway because those 30 micron bags are really just fine-dust pumps.

JR