# Need some opinion on setup



## charlo489 (Oct 14, 2015)

Hi guys, I've been reading for the last 10 months about dust collection, got scared by Bill Pentz, read some more on dust cyclones etc.

My needs are pretty simple, I only have a table saw and router table that are both under a basement window. My goal is to vent outside. I already enlarged the table saw port to 6". Since I'm venting outside and using a top hat baffle, do you think buying a 3hp, 2280 cfm is overkill considering I'll only operate the system on one tool at a time ? We're talking a 7 feet run of 6" piping with some elbows ? 

Do you think a 1200 cfm would be strong enough for a 6" system ?

I live in Canada, it doe get cold, but I'm thinking I won't run the system for long periods of time as I don't use the saw very often, so I don't think my heating will increase much but any input would be appreciated.

here's what I'm planning to get, I'll only use the blower and motor

https://www.normand.ca/en/normand/s...-3hp-220v-2-microns-steel-city-80-310s3b.html


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## sunnybob (Sep 3, 2016)

First question, whats outside the window? No point blowing all your dust out there to have it come straight back in the kitchen door.

Second question, if youre buying all that why arent you using it all?

Once youve answered those, thats way more than you need for a single machine on a short run of pipe.


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## charlo489 (Oct 14, 2015)

well by not using the saw often, I mean I'm just a hobbyist so I'm not sawing everyday...it can be weeks before I use it like most members here, let's be honest. The window is perfectly placed so no issues with dust re-entering the house !

I also believe that the model in the link might be overkill but do you think a 1200 cfm unit could do well with 6" piping ?


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## djg (Dec 24, 2009)

I'm no expert, but I would think that is way overkill for just a table saw or router. I recently redid my DC system using my Jet 1200cfm DC. I had way too much ducting for it to work properly. I still have more than your 7 feet and it works great.


So you're thinking about buying just the 1200cfm blower and motor and mounting it at the window?


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## charlo489 (Oct 14, 2015)

Yes I will only use the motor and blower and mount it over a diy chip separator (top hat baffle design) and then vent outside. What pipe diameter are you using with that 1200 cfm ?

I remember seeing a chart table on bill pentz website about cfm and that's how I came up with my 3hp model...every model seems underpowered according to Pentz but at the same time, I think he's also selling dust collector systems so I'm skeptical


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## djg (Dec 24, 2009)

Sorry, I meant to say, I run 6" duct also.


A lot of good info from others in my redo link:


https://www.woodworkingtalk.com/f32/piping-210123/


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## woodnthings (Jan 24, 2009)

*I'm going from memory here ....*

If I recall, the CFM needed to collect fine dust is in the neighborhood of 1000 CFM. That's well beyond the capacity of most "home shop" stationary dust collectors, which are around 400 "actual" CFMs.
See Bill Pentz statement on "Fine Duct Collection" at the very bottom of this link:
http://billpentz.com/woodworking/cyclone/beginnnerscorner.cfm



Here's what I have learned. Older table saws are one of the most difficult machines to efficiently collect the dust from because most often there is a large cabinet below the blade and about 30" of "free fall" to the dust port. Newer table saws like the Saw Stop, have a blade shroud right around the blade with a shop vac dust port to collect the dust, a much better solution. The dust on the older saws settles down out of the air stream and falsl to the bottom port, not very efficient.


In addition, some dust is always throw up into the blade guard over the blade if there is one in place. An "over arm" dust collection accessory is available for the Saw Stop as well, but most are quite expensive. I have experimented with 2" PVC sections and 90 degree eblows on my table saws with some success. I use a shop vac which has a high velocity air stream which can be focused right at the blade, unlike a stationary dust collector which has a lower velocity air stream, but higher volume.


Again, the blower motor and fan/impeller are typically undersized for efficient fine dust collection as is the ducting, which Pentz likes to see at 8" diameter:
http://billpentz.com/woodworking/cyclone/equipment.cfm#FansNFanTypes


Let's understand that we are not "sucking" the air through the system, like you would drinking from a straw creating a vacuum. The impeller is "pushing" the air through the system and into the filter and unless the filter can breath properly because of it's large surface area, it won't work efficiently. That's why bag filters are not as efficient as cannister filters which have more surface area. Also the porosity of the filter material on a bag is typically more open than the cannister types. I don't own a Wynn filter, but they are widely acclaimed for their performance. Outside venting is certainly more efficient, but there will be some heat loss AND if there are flame fired appliances like hot water heaters or gas furnaces, it may reverse the exhaust fumes, creating a CO hazard. Most newer furnaces have their own fresh air supply, so that's not an issue.
See the section on Basic Components here:
http://billpentz.com/woodworking/cyclone/equipment.cfm#FansNFanTypes




Also understand that air velocity and air speed are not the same, see section 6 here:
http://www.billpentz.com/Woodworking/Cyclone/dc_basics.cfm#HowMuch



CFM requirement chart for the basic stationary machines based on 4000 FPM air velocity:
http://www.billpentz.com/Woodworking/Cyclone/dc_basics.cfm#CFMRequirementsTable


As small shop owners, we are uninformed for the most part and under equipped in the final application of the ducting, motor impeller and filters. I do know that even with the best intentions and the most affordable equipment, we won't collect all the fine dust. I use overhead air filtration, but is it on all the time? ..no. Do I wear a respirator or dust mask all the time? .... no they are clumsy and sweaty.


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## danrush (Oct 16, 2017)

It seems to me that you should consider how to make up the 1000+ cfm that will be pumped outside. I know that the hvac guys need to provide make up air whenever they install a 600cfm or greater kitchen hood vent in our area, per code. As noted earlier, it's not so much heat loss, but also combustion exhaust concerns. 

Sent from my SM-J337V using Tapatalk


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## charlo489 (Oct 14, 2015)

there's no concern regarding exhaust, here in Quebec everything runs on electricity, we don't have gas water heaters or furnaces like you guys have so just cracking a window will solve the problem.


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## redeared (Feb 7, 2019)

My basement shop is not that big, but what works well for me is a 200cfm inline fan ducted to the outside via the dryer vent. I set it up mainly to exhaust VOC's during the winter when I can't open the basement door, but with inexpensive 4" dryer vent hose and couplings I can move it around to the areas I'm working in for dust collection. In the past my dust levels where enough to set off the smoke alarm on occasion.

On laundry days everyone knows to check the connection to the blower and reconnect it to the dryer, its a slide off/on connection so it's not a big deal.


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## QuickConnexion (Jan 21, 2019)

Interesting YouTube video of an economic dust collector system :


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## djg (Dec 24, 2009)

I have one of those devices that turn on the DC when a blast gate is opened. I do like this method better, though. Just flip on your tool and the DC turns on also.


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## charlo489 (Oct 14, 2015)

well, I pulled the trigger and got a steel city 2hp dc. 1550 cfm with an 12" 3/4 impeller. Overall I'm satisfied but wished my overarm collector was a bit more efficient. I'm using a 6" port on the cabinet with a 6" pvc mainline and a 4" flex hose reduced to 3" at the guard.


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## woodnthings (Jan 24, 2009)

*You won't like my advuce .....*



charlo489 said:


> well, I pulled the trigger and got a steel city 2hp dc. 1550 cfm with an 12" 3/4 impeller. Overall I'm satisfied but wished my overarm collector was a bit more efficient. I'm using a 6" port on the cabinet with a 6" pvc mainline and a 4" flex hose reduced to 3" at the guard.



You did a nice job on the fabrication, but the flaw is in the "split" system, it's can't keep up and the suction a few inches away from the opening is greatly diminished. The best overarm method I've come up with is using a shop vac with it's high velocity but "focused" inlet right on top of the blade. Your blade cover is too wide which results in less "at the source" vacuum/suction..... That's just my opinion based on quite a lot of experimentation. 



Here is one example of my system, it's OK, but not the best one. I can't reveal that one for privacy reasons and potential inventor's rights.... sorry.












Another variatioon:


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## charlo489 (Oct 14, 2015)

yeah I'm also thinking my guard is too wide. However, it must say that the only dust that doesn't get sucked by the overarm is when the cut is finish...the last 1/2" or so. So I would say that 95% of the dust is removed. I might give the shop vac thing a try


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## charlo489 (Oct 14, 2015)

All right so I've been thinking how I could improve my dust collection at the guard and came up with a much better solution ! I redid my guard but this time, no plexiglass and the 3" pipe is now sitting 1" on top of the blade instead of 3 or 4" on the previous one and it's also closer to the front of the blade, where much of the dust is generated. I added some silicon rubber all around the guard to maximize the succion. I did a test with mdf, which is the worst dust producer ever and almost nothing came out...like 3 specks of dust at the end and that's it !


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