I’m sure this has been asked about a million times, but here goes.  I’ve done soooo much to control dust collection in my shop, but I think I must be doing something wrong because I have dust, (not a little but a lot) My shop is 1/2 of a 2 car garage. I have a Laguna C Flux 1.5 HP dust collector.  I have a 4 inch hose lying on the floor that goes to my table saw, miter saw and bandsaw. Everything else is being collected by a rigid shop vac.  So my question is this, should I run pvc piping to these machines? Or is the hose laying on the floor good enough? I do have gates on the machines and wonder if I should leave them all open, or only open the one I’m going to use..?

Pauley,

Perhaps this article from Wood Magazine will help.

https://www.woodmagazine.com/figure-dust-collection-needs-by-the-numbers

Per the URL, your system is less effective with the hose vs ducting.  The more hose/ducting the less effective.  A 1.5 HP, 900 CFM is not a large system.  IMP your system can only effectively collect dust for one-two machines.  I use a shop vac on my 14" bandsaw and am satisfied with the collection.  I do not believe a shop vac can effectually collect saw dust for a planer and jointer.   Most miter saws are dust machines.   My 2c.  Danl

I guess a lot depends on the way your saws are made. 

 

My table saw is a "contractor's" saw. I added a dust collection shroud to the bottom opening then added a removable plywood cover on the back where the motor/belt enters the saw as well as a cover over the slot opening for tilting.

 

My bandsaw has a dust collection port but the lower door doesn't seal that well- inexpensive Taiwanese saw. Lots of leakage there. Sealing the door would require some reverse engineering to allow easy access for blade changes.

 

Miter saws are notorious for poor dust collection. I made an adapter to connect a hose where the bag was installed. Not efficient. 

 

Edit: Agree with everything Dan. My Dust collector is terribly underpowered and I am using flex hose. I do have blast gates so only one machine at a time is connected to the collector. According to Mimi, I don't have dust collection (my shop is in the basement).

19 hours ago, Danl said:

Pauley,

Perhaps this article from Wood Magazine will help.

https://www.woodmagazine.com/figure-dust-collection-needs-by-the-numbers

Per the URL, your system is less effective with the hose vs ducting.  The more hose/ducting the less effective.  A 1.5 HP, 900 CFM is not a large system.  IMP your system can only effectively collect dust for one-two machines.  I use a shop vac on my 14" bandsaw and am satisfied with the collection.  I do not believe a shop vac can effectually collect saw dust for a planer and jointer.   Most miter saws are dust machines.   My 2c.  Danl

 I thought my dust collector was much better than the harbor freight one I had. I tend to read to much about this and that’s what is causing my confusion.
Where you say it’s less effective with hose than ducting…would it be greater or just slightly better with ducting as apposed to the 4 inch hose?

Edited January 16, 20251 yr by Pauley

19 hours ago, lew said:

I guess a lot depends on the way your saws are made. 

 

My table saw is a "contractor's" saw. I added a dust collection shroud to the bottom opening then added a removable plywood cover on the back where the motor/belt enters the saw as well as a cover over the slot opening for tilting.

 

My bandsaw has a dust collection port but the lower door doesn't seal that well- inexpensive Taiwanese saw. Lots of leakage there. Sealing the door would require some reverse engineering to allow easy access for blade changes.

 

Miter saws are notorious for poor dust collection. I made an adapter to connect a hose where the bag was installed. Not efficient. 

 

Edit: Agree with everything Dan. My Dust collector is terribly underpowered and I am using flex hose. I do have blast gates so only one machine at a time is connected to the collector. According to Mimi, I don't have dust collection (my shop is in the basement).

Thanks Lew.  I do have a cabinet table saw. I also have a grizzly’s inch band saw, and I I do agree the doors don’t even come close to sealing properly and collecting the dust from that just doesn’t seem realistic.

It's commonly though that the flex hose has about 3x the drag on air flow versus smooth piping. This isn't conjecture, it can be measured. That's a significant reduction of low. Reducing the sue of flex may not solve all your problems, but it should help quite a bit.

2 minutes ago, Fred W. Hargis Jr said:

It's commonly though that the flex hose has about 3x the drag on air flow versus smooth piping. This isn't conjecture, it can be measured. That's a significant reduction of low. Reducing the sue of flex may not solve all your problems, but it should help quite a bit.

Thank you Fred. I think that’s what I was looking to find out.  So I think I’ll pipe my dust collector to my table saw and my bandsaw saw.  They are the ones with a 4 inch port.

You should be good enough with flex pipe.

2 hours ago, Pauley said:

 I thought my dust collector was much better than the harbor freight one I had. I tend to read to much about this and that’s what is causing my confusion.
Where you say it’s less effective with hose than ducting…would it be greater or just slightly better with ducting as apposed to the 4 inch hose?

The Wood magazine link provides a PDF link which gives you a good relational number when comparing flex hose to solid piping (I agree with Fred).  It also addresses  performance loss due to using elbows.   Danl

He’s running a 1.5. I’m running a 1.5. How much do you think he can  be losing between solid and flex? It only matters when it’s your job is to sell it.

Edited January 16, 20251 yr by BillyJack

There's so much more to it than HP. Impeller size and shape, filtration, the separator if there is one, the ports on the tool all play a part in how much air his DC moves. But the flex is a big drag and generally speaking less is better.

Edited January 16, 20251 yr by Fred W. Hargis Jr

Fred I’ve learned not to get caught up in everything, but sometimes you just need to look at the basics and go from there. I’ve learned not to blow up my head over every little tweak.

 

Figuring out a DC is like trying to understand a full blow; hot rod at the track. We understand what parts are and there names, but we won’t understand it all and how it functions..

Edited January 16, 20251 yr by BillyJack

I run a shop fox 1.5 with a 6” coming off reduced to a 5” head pvc down to 3” to flex. I can run the edge sander and table saw. Table saw and router. Only time I turn off tye table saw is wit( the planer.. Ive never taped off my lines but I know it would help, but it runs fine..

 

For the hobby shop, it’s fine. Funny the use of calipers, etc in woodworking.We rarely use them in the cabinet and furniture industry..

 

I have enough problems with spell check

Edited January 16, 20251 yr by BillyJack

Go back to the original post, Jack. Pauley isn't seeing the kind of dust collection he wants with what he haves. All we are doing is trying to help him get it to perform better. We all have different expectations of what "good" DC is. Yours are different than mine, and different than Pauley's. What he has isn't apparently meeting his expectations. No one is disputing what you have is fine for you.

Edited January 16, 20251 yr by Fred W. Hargis Jr

No problem Fred..

 

I can’t see his setup. No pictures, but flex pipe isn’t causing his problem.

 

Dust is in every shop, there is no 100% . He says he has a lot. We would to see this setup.. it could be be his straps on his  connections, etc..

Edited January 16, 20251 yr by BillyJack

Never messed with biscuits or dominoes but I do like dowels for mitered corners, not for alignment but to help hold it together, especially cabinet doors. The way I see it, the glued surface of the dowel is along it’s side grain and the side grain of the hole it’s in. So once the joint is glued together your using the tensile strength of the dowels as insurance to keep the miters tight and the door from racking in case a little kid wants to swing on it.

Yes Flex will carry dust .Flex causes turbulence in airflow and this will result in less effective performance. My DC is Grizzly 1.5 HP with a canister filter. The canister makes a huge difference. Yes close off all stations not in use. Bends should no be a direct 90 degree but a gradual 90. You can use two 45 degree bends to accomplish this or look in electrical for a long 90 (much more expensive. Like Billy Jack said use the largest hose possible from the DC till ready to run down to the tool.

Hope some of this helps.

Keep in mind that wood tools create velocities in the 1000's of feet per minute, and a typical opening in the tool only has about 100 fpm of drag to offset the particle speed.  In other words, you're never going to get complete capture of dust, especially from a "consumer" sized system.  I've done industrial systems with 50~75 hp motors, and what you find inside the building are piles of uncaptured dust.  it just comes with the territory.  Replacing flex duct with smooth typically improves air flow, but only by about 10%.  Using gates at each tool so you can focus all the air on only the tool in use is much better; that probably gets you about 20% increase.  But whatever you do, you won't get better than about 80~90% dust capture at a typical tool.

Sorry, about any confusion a couple of posts back. I thought I was replying to a joinery topic, not sure what happened there.

He’s running a 1.5 as I. If the canister is the difference , then a bag would be better..I put in one complete system at one shop and helped on a larger one at tyehe furniture factory..