# Dust collector ??????



## papawd (Jan 5, 2011)

O.K. not sure if the best place for this discussion but since breathing dust is very unsafe guess this will do.... I am getting myn dust collector on Mon. and am curious if running a 4" hose to my saw then one adapter to 2 1/2" would be better than adapting 4" to 2 1/2" at the dust collector then running the 2 1/2" hose to the saw ???? I am thinking the run would probably be better with 4" hose which would give a larger air flow ?????


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## jlord (Nov 16, 2009)

Use the reducer at the machine it is attached to. Most of your run should be the 4".


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## DaninVan (Jan 1, 2012)

What James said, Warren. 
The biggest issue will likely be chips from dadoeing plugging up the 2.5" pipe; the shorter the 2.5" section the better. I cut a lot of fairly wet lumber, especially cedar, and it's definitely an issue for causing jams, especially if slivers of wood or bark get into the hose.


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## DeclanJustin (Mar 10, 2012)

I have a Jet DC1100 1-1/2 hp Dust Collector, I am wondering what's the best way to set it up for dust collection in my small 10×12 shop?


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## AaronRC4 (Feb 27, 2012)

*6" hose!*

You didn't say what DC you have but it doesn't make much difference on the size of duct work you need. According to Pentz and my shop uses what he recommends, 6" PVC S/D (that stands for sewer and drain) thin wall pipe is necessary. Typical DC's have very low suction. A vacuum cleaner which uses 1-2" hose has a SP(static pressure) when operating of about 35-50" of suction. It takes this much to move air though a small diameter pipe. A DC runs at about 7-8" Sp and you have to use 6" diameter or you will choke it off and reduce your CFM which is what picks up the sawdust. 

Under no condition use 2-3" duct. Even 4" will starve the airflow but sometimes you have no choice. 

A very common post is" I have a very small shop and don't need a big DC". Very bad logic. The machine cannot tell if its in a big or little shop and spews out the same amount of dust. The dust concentration will be higher in a small shop. Not good for your lungs.

Dust collection is expensive to set up. Don't do it twice by buying to small. 

Rules are 1- run 6" PVC from the collector to the machine. No step downs. 2. Make your own blast gates. The ones you buy are usually awful and fit inside the duct work and choke it off. You can make a 6" manual gate for about $5.00. Lots of articles on the web. Goggle" Blast Gates Halbert" to see an example of a automatic blast gate. 

3 Exhaust out side if possible. If you can't because of weather use canister filters. Wynn is a good source.

Impeller size is every thing .Minimum is 14" with 15" for cyclones. Check out the Pentz site but don't get bogged down with to much confusing data. KISS and good luck.


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## Tommyt654 (Apr 5, 2009)

Your correct in running a 4" hose vs 2 1/2.I would enlarge the collection port on my saw to 4" if I was you, the cfm is most critical here as that what mostly draws light dust to your collector. I would also build or buy another chip collector to place in between the unit and the d/c like Cochesuga had done in his review on here somewhere.While static presure is a factor, not so much unless your really flowing a ton of air,most small shop units rated a 1 1/2 to 2 h.p are really only flowing maybe 6-800 cfm at best and the 4 inch piping will work fine for that, when you get into larger units say like 1100Cfm up then you should really consider a larger pipe,like a 6 inch, but not until you hit that majic number are you reallly gonna see any benefit over a 4 in. pipe IMO


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## DaninVan (Jan 1, 2012)

Tommy, no argument with your numbers but having said that, running the 6" pipe means not having to redo the piping should the DC ever be upgraded to a larger m/c. If that ain't gonna happen then no argument from me.
A quick reminder to ensure the at the pvc is grounded for it's entire length. There's a previous thread with an article describing a simple effective grounding method for pvc here somewhere...


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## AaronRC4 (Feb 27, 2012)

The area of a 4" hose is 12.5 " sq. The area of a 6" hose is 28.3" sq. That's 2.25 time bigger. A DC 1100 Will flow about 783 CFM @4.12" SP and 424 CFM @ 6.66" SP. Thats a huge difference in performance so do every thing possible to keep the SP as low as possible by using 6" duct or hose. The DC1100 comes with a 6" single inlet with a 4" duplex which should not be used.

I have the TESTO numbers run by John Otto of Jet Tools . Some where on the net they should be available . The current numbers used in Ads are not correct. The DC1100 uses a 11" impeller. If you want to hot rod your unit buy a DC1200 impeller. They have the same shaft size and are interchangeable. Just don't run the unit with out ducts installed and check with an ammeter. 

When using plastic duct or flex hose the easiest way to get rid of static shocks is to spray the plastic on the outside with "Static Guard" . This works very well for Vac hoses and I've used it for years. Lasts up to 6 months.


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## gwizz (Mar 3, 2012)

Remember the following points :

Your dust collector pulls a fixed volume of Air ( 1,200 to 1,600 cfm )
your piping system needs to maintain over 3,000 ft per min to carry the wood dust etc.
bigger pipe fixed volume less speed
these system assume home shop use with 4" main piping and smaller hose pickup at open area ( like router table tops ) 6" is too big and air would slow down dropping it's heavier particles in the pipe causing blockages.
use blast gates so that only the machine working at the time gets all the volume.
4" to saw, planers etc is great, smaller flex to pickup points increases speed and suction on router fences etc.
if machine is equipped with a DC port that's the size you should reduce to to pickup as it will give the ideal intake velocity for the design of the machine. 

STATIC arcing is a fire hazard in plastic pipe and dust collector bags etc, spraying stuff or running grounding on the outside of the pipe does NOTHING for the static being generated on the inside of the pipe which is the fire hazard !
. 
.


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## Mike (Nov 22, 2004)

Most home dust collecters are designed to work with 4" hose; this provides the right amount of air flow for the collecter to function at it's best.


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## Phil P (Jul 25, 2010)

gwizz said:


> STATIC arcing is a fire hazard in plastic pipe and dust collector bags etc, spraying stuff or running grounding on the outside of the pipe does NOTHING for the static being generated on the inside of the pipe which is the fire hazard !


Hi Richard

I think you'll find that this page by Dr. Rod Cole pretty much disproves that theory. 

Most of the fires I've heard about in dust collection systems are because people have been collecting from sanders, there have been sparks where abrasives have hit impellors and the sparks have subsequently smouldered and caught fire in the waste bag many hours later. This is a very good reason why we all need to remove ALL dust bags/drop boxes from extractors at the end of day/session and place them outside the building, or at the very least inside a closed metal bin or container where any fire hazard is contained

Regards

Phil


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