DC ducting sizes

[Harvey Pascoe]

Here goes again, more DC questions. :eek:

My Delta 50-760 dust collector arrived today and as calculated it barely fits in my 2 car garage shop without causing major space restrictions. But the one thing I did not plan on is the amount of space and problems created by upgrading from 2.5" to 4" ducting. All my machines are clustered at the door end of the shop but the obvious solution for ducting is to go overhead and down with the problem of leaving space for the overhead door, so I will have to use PVC pipe supported from the floor (ouch, its gonna be messy looking).

I've read a lot about the ducting sizes people use with a 4" DC, anywhere from 6,5, and 4" main ducts for a 4" DC inlet port. What size main ducting should I use from the DC and running overhead? This would be rigid PVC pipe. Will a 4" main be adequate for one machine at a time operation?

My router table will not accommodate a 4" duct without major alterations (underside port). Will reducing it from 4" to 2.5" reduce the effectiveness when it presently works fine with 2.5" hose with a Shop Vac?

[Neil Brooks]

You'll be fine with 4" pipe.
You'd be better with 5", but you'll be fine with 4"

Enjoy. The 50-760 is a lot of bang for the buck !

[david brum]

My router table will not accommodate a 4" duct without major alterations (underside port). Will reducing it from 4" to 2.5" reduce the effectiveness when it presently works fine with 2.5" hose with a Shop Vac?

Yeah, 2.5" hose won't work nearly as well as it did with your shop vac. DCs really lose their effectiveness below 4". You'll be better off upgrading to 4" or sticking with the vac for your router.

[Harvey Pascoe]

I got the machine assembled and running. Wow! This is a whole new world of dust collection. That thing will suck the socks off your feet. I was worried whether the suction would overcome gravity to pull heavier chips up 4" verticals. Now I see that is not an issue. I will put three 4" verticals down to the machines and branch off to 2.5" where needed at machine level. BTW, I tried 2.5" and the suction is easily double that of the shop vac and worked reasonably well on the band and table saw, leaving a bit of dust on tables, but far better than the big Shop Vac.

As it is, I will add the garbage can separator as I can see this is going to suck up a lot of unwanted things when cleaning and the can will make it easier to retrieve them, plus not having scraps go through the impeller blades.

Going overhead, this is going to be easier than I thought. Thanks for your help.

[John Williamson]

I use 4" PVC with no problems. Did all the research on larger pipe and the system would theoretically be more efficient using 5" or 6" but bottom line is that it works and no chips are left in the machines at the end of the day. Larger diameter pipe could pull more CFM and possibly pull some more fine dust into the collector but the overhead filter keeps things clean in the shop. Also my house hasn't exploded and I haven't been killed with a static electricity shock from the PVC.

For the average home user you should be fine.

[Glen Blanchard]

Here goes again, more DC questions. :eek:

All my machines are clustered at the door end of the shop but the obvious solution for ducting is to go overhead and down with the problem of leaving space for the overhead door, so I will have to use PVC pipe supported from the floor (ouch, its gonna be messy looking).

Harvey - I recently completed my DC system in my own 2 car garage. I have the Oneida cyclone and their metal ductwork. I had the same dilemma as you regarding how to get the ducting to the machines sitting under the garage door and still have the door operational. My solution was to string a guy wire with turnbuckles from one end of the garage to the other, sitting under the opener tracks. The duct work is supported by the guy wire with additional supports fastened to the garage door track on each end of the door. This arrangement prevented me from having to bring any vertical supports to the floor. Just another option for you.

[Chris Padilla]

I use 4" PVC with no problems. Did all the research on larger pipe and the system would theoretically be more efficient using 5" or 6" but bottom line is that it works and no chips are left in the machines at the end of the day. Larger diameter pipe could pull more CFM and possibly pull some more fine dust into the collector but the overhead filter keeps things clean in the shop. Also my house hasn't exploded and I haven't been killed with a static electricity shock from the PVC.
For the average home user you should be fine.

The point of the larger diameter pipe IS to get that fine dust. The overhead filter is fine to keep the shop clean but it does zero for the dust that is in the air while you are there cutting and breathing unless you have a mask on or something.

[Alan Schaffter]

The point of the larger diameter pipe IS to get that fine dust. The overhead filter is fine to keep the shop clean but it does zero for the dust that is in the air while you are there cutting and breathing unless you have a mask on or something.


Yup!!!:) and a 4" inlet is way too small!

[Bob Riefer]

Taking household contamination out of the equation for a moment (because many operate in a detached space, or otherwise handle that issue.. too many variables):

Assuming a 4" pipe is getting all the visible material, AND that the operator is willing to wear a respirator... wouldn't 4" be alright then? That is, 6" would let you take the mask off, but otherwise wouldn't have much benefit if you're already getting a nice tidy shop with 4" pipe.

I'm not stating, I'm asking :)

Thanks

[Alan Schaffter]

Taking household contamination out of the equation for a moment (because many operate in a detached space, or otherwise handle that issue.. too many variables):

Assuming a 4" pipe is getting all the visible material, AND that the operator is willing to wear a respirator... wouldn't 4" be alright then? That is, 6" would let you take the mask off, but otherwise wouldn't have much benefit if you're already getting a nice tidy shop with 4" pipe.

I'm not stating, I'm asking :)

Thanks

That is a big assumption. Even big DC's don't get all the "visible" dust. If they don't get all the visible dust then they certainly are not getting all the fine dangerous stuff (if I remember 25 microns is visible, the dangerous stuff is .5 to 10 microns.) Regardless, no way that 1.5 hp DC is gonna get all visible dust through a 4" ducted system. That single stage unit is designed to be rolled right up to the machine and be connected with a short length of flex. Run the numbers and you will see. Bottom line, you need to run the numbers to see what kind of CFM you are getting at each machine. It may be that DC is optimized for only 4" pipe.

He might be breathing ok through a mask but what about the rest of the house and family when he is done for the day. Unless he strips and hits the shower first, he will carry a lot of fine dust into the house on his clothes, hair etc.

[Chris Padilla]

Taking household contamination out of the equation for a moment (because many operate in a detached space, or otherwise handle that issue.. too many variables):

Assuming a 4" pipe is getting all the visible material, AND that the operator is willing to wear a respirator... wouldn't 4" be alright then? That is, 6" would let you take the mask off, but otherwise wouldn't have much benefit if you're already getting a nice tidy shop with 4" pipe.

I'm not stating, I'm asking :)

Thanks

Bob,

Generally speaking, going to 6" diameter is going to grab more stuff from cutting operations. However, some systems may not operate at their peak efficiency through a 6" pipe...they might well need a 4" pipe or 5" but that simply means that the system is not a good one to grab the small stuff. But, keep in mind, THE KEY to grabbing as much as possible is sound shroud/hood design at the source of the dust. This is the big challenge. One might be able to make up for poor source collection with an air source having the ability to remove chrome from a trailer hitch but most of us don't have such a thing.

[Greg Portland]

He might be breathing ok through a mask but what about the rest of the house and family when he is done for the day. Unless he strips and hits the shower first, he will carry a lot of fine dust into the house on his clothes, hair etc.This isn't asbestos, it's wood dust. Minute amounts of wood dust in his hair or clothing is going to be a minimal concern given the volume of air & amount of dust that could effectively fall off his body and become airborne. I'm assuming that he'd blow himself off with an air compressor before entering the house (if I walked into the house all dusty my wife would not be pleased).

4" pipe is fine for chip collection but will definitely allow the fine dust to escape on larger machines.

[Chris Padilla]

This isn't asbestos, it's wood dust. Minute amounts of wood dust in his hair or clothing is going to be a minimal concern given the volume of air & amount of dust that could effectively fall off his body and become airborne. I'm assuming that he'd blow himself off with an air compressor before entering the house (if I walked into the house all dusty my wife would not be pleased).

4" pipe is fine for chip collection but will definitely allow the fine dust to escape on larger machines.

Bill Pentz would disagree with you vehemently! :) It all depends on one's tolerance level to sawdust.

[Neil Brooks]

Bill Pentz would disagree with you vehemently! :) It all depends on one's tolerance level to sawdust.

I think it's a very fair point, however, to -- metaphorically -- draw a graph for people, highlighting percent capture vs. dollars spent.

The OP should get adequate information, but -- like all of us, in most things -- has to decide where he/she wants to fall, on that curve.

As an aside ... I'm really enjoying my (used) copy of Sandor Nagyszalanczy's "Woodshop Dust Control."

It's NOT going to incite me to re-wire my house for 440V, and put in a 25HP DC with 18" ducts, but ... it is an interesting read, and provides a comprehensive overview of DC.

[Harvey Pascoe]

Wow, some people are really paranoid about dust. Heck, I'm going from a lot of dust down to almost nothing I can see in the halogen spotlights over my bench, so I'm not going to worry about what I can't see.The pollen around here is 50 times worse. I've now tested the unit with mock up connections and the results with 4" were excellent.

I did get the garage door problem solved quite easily. Ran the pipe all the way across with brackets on the ends (22') and one middle support where a down leg will b anyway, so no problem with that.Hey, I can hang tools on it. Once I put pencil to paper all sorts of possibilities popped up and it turns out to be far less complicated than I thought. In one days time the job is already half done.

Started with setting up a separator (which many say isn't necessary, but is if you want to easily recover those things you accidently suck up and prevent chunks of wood from going through the impeller) with a 40 gal steel can, making the lid and ports. That went easily and quickly, then on to Home Depot for the myriad PVC fittings which, miraculously, I got right the first time, surely by pure luck. By end of day the overhead main was installed with drop down tees. Just had no idea how quickly one can fit up this stuff when you plan ahead. Also, I didn't glue any pipe, just drilled and screwed so any changes will be easy to make. The main has to come down tomorrow because I forgot to install the grounding wire.

[Anthony Whitesell]

Careful Harvey or you'll start on paranoid topic #2...grounding PVC. :D

[Brad Gobble]

Bill Pentz +1

'nuff said

[Chris Padilla]

Careful Harvey or you'll start on paranoid topic #2...grounding PVC. :D

Oh no!! :D I'm still trying to figure out how to "ground" an insulator...the physics just won't let me. ;)

[Joe Leigh]

I usually avoid these threads like the plague but this one was particularly amusing. The OP is a hobbyist with a small shop in his garage. A 1 1/2hp system with 4" duct is light years ahead of a 2 1/2" shop vac. It's not the space shuttle or a clean room at IBM or an operating theatre. It's a garage, sheesh...
Can we get through one dust collection thread without all the drama of the life threatening exposure with anything short of a custom 5HP Cyclone system with 6" mains, or without quoting chapter and verse from some dust guru or other?
How about airborne particles not generated from the shop? How about pollen? Pet dander? How many dust "experts" are smokers?
Some folks here need to lighten up. These dust collection threads are starting to resemble the myriad useless SawStop and Festool threads.

[Greg Portland]

Bill Pentz would disagree with you vehemently! :) It all depends on one's tolerance level to sawdust.
I have to assume that you just read my post and not the thread of posts to which I was replying. The question is can someone wear a full respirator & just perform chip collection (4" pipe, 1.5HP DC, etc.). I say yes assuming they dust themselves off (vacuum, air compressor blow off, etc.) before they enter the home. If you don't agree with this then how do you empty your chip bin safely? Most people put on a respirator & dump the dust/chips (or bag it and dump it). Either method will expose you to dust.

[Greg Portland]

Heck, I'm going from a lot of dust down to almost nothing I can see in the halogen spotlights over my bench, so I'm not going to worry about what I can't see.That is the stuff that is most harmful. However, you can assess the risks yourself and do what you want.

[Kirk Poore]

If you don't agree with this then how do you empty your chip bin safely? Most people put on a respirator & dump the dust/chips (or bag it and dump it). Either method will expose you to dust.

I drag my 44 gallon trash can outside to my 90 gallon trash bin and dump it while holding my breath and standing up wind. No respirator, no problem.

Kirk

[Chris Fournier]

I've got to agree with Joe Leigh.

If you're gonna put on the Bill Pentz Club dust detector ring and wring your hands about every last deadly speck of dust in your shop then I think that woodworking is likely not for you; perhaps instead you should set up to make computer chips in your shop.

Not to knock Bill Pentz and his generous sharing of his research and opinions, I appreciate them and the effort they took. This does not mean that I have to adopt his standards or outlook by rote.

Over the years I have progessed from shop vac to single stage DC to just now the purchase of a cyclone and metal spiral ducting ($$$ouch). In the scheme of things my new DC system makes sense as I've recently bought some much larger equipment that brought on chip/dust issues that I didn't have with my earlier equipment.

The world is full of hazards that shorten our now incredibly long, healthy lives but we need to keep things in perspective. Perspective does seem to be somewhat lacking in these DC threads.

Some guys like to build furniture, others like to build shops and still others like to build DC systems. Which guy you are has everything to do with your outlook on this topic!

[Chris Padilla]

The question is can someone wear a full respirator & just perform chip collection (4" pipe, 1.5HP DC, etc.). I say yes assuming they dust themselves off (vacuum, air compressor blow off, etc.) before they enter the home.

Sounds perfectly reasonable to me.

I heard a saying once that was quite interesting: There are no toxic substances...only toxic levels.

We all have to decide our tolerance levels. Bill Pentz cannot handle a 1/2 micron dust spec...others can smoke 4 packs of cigarettes every day for 50 years and live to be 90.

My point is to simply INFORM...not scare...and not preach. As long as you have all the (correct) info, make your choices and happy woodworking! :)

[Harvey Pascoe]

Well, I did ground my ducting since I have an understanding of static electricity. BTW, you don't ground an insulator, you provide a ground for the charge that develops from air friction, the same as lightning. Air turbulence static is lightning. Notice how you get shocked when you touch your car in dry winter air? Its not grounded but has sufficient mass to be a grounding source.

Anyhoo, way off topic and I'm not paranoid about dust (except for cocobolo) since I spent 40 years in a far worse environment and I'm still here. I'm not a hobbyist, I make my living in that puny garage shop. I'm ugrading from a Shopvac and a garbage can, fer goshsakes. I can either spend my time making product or perfecting a shop, not both. As it is I'm down a week's production time to get the DC installed. However, I enjoy the banter between perfectionists and producers, I just wonder where the perfectionists get the bucks to strive for perfect shops. By woodworking? Some of you folks, judging by your shop pix run substantial commercial operations and your revenues may support massive and complex ducting. Others seem to have other (very good) sources of income. Have some consideration in your answers to who is asking. No garage is going to accomodate 6" ducting and still leave room for work.

I have no intention of living to be 90 so screw the subatomic particles! I also smoke cigars, so that should get the dander of you "utterly clean and green" types up.

[Joe Leigh]

I like your style Harvey...and no disrespect intended with the "Hobbyist" reference.
Smoke 'em if you got 'em...

[Harvey Pascoe]

I liked the quip about making computer chips!

[Chris Fournier]

I really enjoy walkng into my shop the morning after I smoked a cigar the evening before.

As Robert Duvall said in Apocalypse Now: "...it smells like victory."

I hope that they never create a filter that robs me of this particulate.

[Alan Schaffter]

Well, I did ground my ducting since I have an understanding of static electricity. BTW, you don't ground an insulator, you provide a ground for the charge that develops from air friction, the same as lightning. Air turbulence static is lightning. Notice how you get shocked when you touch your car in dry winter air? Its not grounded but has sufficient mass to be a grounding source.

Anyhoo, way off topic and I'm not paranoid about dust (except for cocobolo) since I spent 40 years in a far worse environment and I'm still here. I'm not a hobbyist, I make my living in that puny garage shop. I'm ugrading from a Shopvac and a garbage can, fer goshsakes. I can either spend my time making product or perfecting a shop, not both. As it is I'm down a week's production time to get the DC installed. However, I enjoy the banter between perfectionists and producers, I just wonder where the perfectionists get the bucks to strive for perfect shops. By woodworking? Some of you folks, judging by your shop pix run substantial commercial operations and your revenues may support massive and complex ducting. Others seem to have other (very good) sources of income. Have some consideration in your answers to who is asking. No garage is going to accomodate 6" ducting and still leave room for work.

I have no intention of living to be 90 so screw the subatomic particles! I also smoke cigars, so that should get the dander of you "utterly clean and green" types up.

Hmmmm, me thinks I detect a bit of sarcasm :) I'll just address two points-

If you haven't done so, read Rod Cole's point paper on static (just Google it). The only thing you are doing by running a ground wire in PVC duct is providing a localized source of grounding and creating the opportunity for a clogged duct. Since PVC is a non-conductor you are only grounding the immediate vicinity of the wire ON THE INSIDE of the duct. The car analogy doesn't hold, because most of the car IS A CONDUCTOR. I've never been shocked by touching the vinyl, leather, or plastic of a car door. Are you running the grounding wire in an attempt to reduce the annoyance of static shock or to prevent some sort of static induced fire or explosion? If you want to reduce the annoyance factor, make sure your machines are grounded, ground the metal coil in your flex, and wrap the first few feet of each drop with foil that is grounded.

"Producers and Perfectionist"- hmmm pretty narrow group of woodworkers. What about those who do both, or most of us in between? I am not a producer, not a perfectionist either, but I have a very nice (award winning) shop- not because I had money to buy nice stuff, but because I build everything and scrounge the rest. I paid less for my 3 hp DC and cyclone than you did for your Delta- I got my DC used from a lumberyard that was closing and I built my cyclone for under $50.

Oh, one more thing, did you mean "drop down tees" literally? I hope you meant wyes.

[Harvey Pascoe]

Yes, unfortunately I did mean T's on the drop-down. I have a situation in which I couldn't figure out how to avoid having one, understanding the drawbacks involved with a T. But my system is not overtaxed so the loss of performance is acceptable to me.

BTW, I placed a glass jar at the bottom of one of my drops. Interesting to see what gravity will place in the jar. So far, screws and chunks of wood.

My production schedule simply doesn't give me the time to do as much "shop made" stuff as I'd like. Sometimes its cheaper just to buy it, as it surely was in this case.