Okay the question is a little arbitrary, but not meaningless.
I see time and time again folks with 4" ducted systems, with reasonably well designed ducting, and the typical 1.5 - 2 HP DC (the average Taiwan job like HF, Shop Fox, Grizzly etc...), and a Wynn type cartridge filter.
I fully agree with Bill on eliminating tight turns, and rough hose as much as physically possible. And for the most part the folks I see setting up their 4" dust collection networks use a pair of 45s and a piece of pipe to make a 90 degree bend, OR they use sweep elbows.
From reading what I can manage to get through on Bill's site, it sure seems like no way, no how, not gonna happen with 4" duct, but I am seeing well laid out 4" systems that people are posting on, using those fancy pants air quality gauges and reporting good results. So what gives?
My tool selection radically limits my options for dust collection, and some of it has been modified, or will be modified VERY soon to accept larger dust collector air volumes.
The tools and ports in question are... (And yes, there are Thien Cyclones in the system here...)
Ryobi BT3100. 1 Factory 2.5" blade shroud port. 1 added 4" belly pan, 1 2.5" shark guard port. The setup here will be 4"x4"x2.5" wye in line with a 4" hose to the belly pan, and a 2.5" line from the 2.5" on the wye to the blade shroud. That will be pulled by the HF DC. An overhead 2.5" to the shop vac. The shark guard 2.5" will get moved to the router accessory dust collection port as needed.
HF 14" Band saw with 6" riser block. Factory dust port removed. sheet lower dust collection blade cover similar to Pentz' illustration in the works. The idea is to cover as much of the lower blade, while making effectively a... well sort of funnel from the table, down into the lower blade guard. A 4" dust port is in the works for the lower blade guard. A 4"x4"x2.5" wye will be in line with the hose, the 2.5" port will be run up to the upper blade guide shroud. Again like in the Pentz diagram.
Northern Industrial 16 speed floor model DP / table. A 4" port will be run here, and as soon as I figure out how to connect it to the fence will be a happy camper...
Ridgid EB4424 belt / spindle sander. With the spindle, the 2.5" seems to work fine, with the belt, it sprays dust everywhere. Can I use the 4" to correct this?
Ryobi AP1301 planer. 2.5" port on the machine. No real way to attach 4", no real fines being created anyway.
Sunhill SM-150B benchtop jointer. 2.5" port. No real way to attach 4" Might be possible to hack away plastic, but probably not a good idea...
ALL freehand routing done outside on a makeshift workbench.
All sanders (Ryobi Corner Cat, Ryobi Quarter Sheet, and Skil Orbital) have 1.25 (ish) inch ports which are hooked up to the shop vac via reducers. I want a downdraft table hooked to the 4" and keep the 2.5" connector to the machines.
Am I on the right track, or do I really need to carve up my equipment and figure out a way to get 6" duct in here?
Basically, can 4" be effective when combined with 2.5"
I've had great success with my 4" stuff. The only time my router table spits ANY chips out is of I'm routing a dado or something, so the fence can't catch stuff. Otherwise it's more like it's peeling away wood it's so good. My setup is 4x4x2.5 Y with the 4" to the cabinet reduced to 3" PVC. Seems to divide the suction quite nicely between the cabinet and fence. I think the key (to any system) is reducing the distance of tubing or hose. I have a bunch of my stuff plumbed directly to the DC, but with a flex connection so I only hook up one at a time. I may connect the TS and miter saw together with some blast gates... we'll see. But it works darn well like this. I think you'll be fine.
Your planer and jointer should mainly produce chips, not fines, so it's more a matter of cleaning up the mess... Belt sanders are next to impossible to effectively collect from, so unless you have an air cleaner nearby, you've probably got the best setup you're gonna get.
My "Air cleaner" is a 20" box fan with a 20x20x1 Filtrete HEPA rated filter attached. It doesn't pull through that tight filter as well as I would like...
I know I need to do something else to address this, but I am not sure what. The DIY fiend in me says build my own air cleaner, the lazy bum in me says wait a couple of pay periods and pick up one of those Steel City air scrubbers at Woodcraft... The lazier bum in me says forget it, just go grab a beer...
My father had an old saying about automobile engines: "There is no substitute for cubic inches."
I think the same thing can be said about dust collection. The larger the pipe, the better.
Problem is, you get to a point of diminishing returns at some point.
And that point varies depending on tools, the size of your shops, etc.
Man, I'm absolutely no help.
I will have to look through my magazines but one had a good design using a squirrel blower and some house filters to use as an air cleaner. If I can find the project I will try to scan and post somewhere for use or will e-mail if someone wants. Wish me luck I have about 200 magazines to look through. :o
Quote from: shrxfn on March 10, 2009, 10:00:49 PM
I will have to look through my magazines but one had a good design using a squirrel blower and some house filters to use as an air cleaner. If I can find the project I will try to scan and post somewhere for use or will e-mail if someone wants. Wish me luck I have about 200 magazines to look through. :o
I've seen a couple different versions of that, and I've helped build one. The trick is finding a squirrel cage blower that runs on 110... If anyone finds one, let me know!! I'm in the market :D
here is one on e-bay.
Blower (http://cgi.ebay.com/FASCO-110-115-AC-electric-blower-squirrel-cage-fan-NEW_W0QQitemZ350173295173QQcmdZViewItem)
sorry did not see that it was sold or ended. Here is another one from everyones favorite hardware store.
HF Blower (http://www.harborfreightusa.com/usa/itemdisplay/displayItem.do?itemid=97762&CategoryName=&SubCategoryName=)
or the big orange box
HD Blower (http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100658973)
I created an air filter from two fans left from a kitchen and bath remodel. A simple box to hold two stacked furnace filters (prefilter and then a better filter) with an exhaust port to allow a kitchen hood fan and a bathroom vent fan to draw air through the box. Works great but have no idea of how much air I am pushing.
Bill is definitely on the right track with his ducting advice, but there are a few things to keep in mind that help to explain the wide variety of opinions out there:
- People have different levels of sensitivity to wood dust (more sensitive people will notice problems before less sensitive people)
- Hood design is extremely important! Often two hoods are way better than one (think tablesaw and cabinet/above table)
- Sometimes you want a small port at a tool (imagine 6" hose at a drill press or router table fence!)
- Sometimes a larger port won't do much like at a restrictive tool like a benchtop planer
- With a less restrictive tool like a big hood behind a CMS, a 6" port is much better than a 4" port and will definitely catch more dust
- 4" ducting is cheap and people often have no idea what they are missing with larger ducting
- etc
I used to have a 1HP DC and thought it was fine for a couple years...until I started coughing and sneezing after a day in the shop. So I upgraded to a 2HP DC. Ahhh! Much better! However, eventually the coughing/sneezing and now sinus headaches started arriving after a day in the shop.
Now I have a large Pentz cyclone with big ducting and have had that for several years now. No problems. Also, my wife has asthma and she's fine in the shop. Bigger is definitely better for us.
When you look at those tool airflow tables you see in magazines that say a CMS only needs 350cfm to clear the debris, what you are really looking at is the theoretical amount of airflow required to remove that type of waste, assuming you have a perfect dust hood. However, back in our shops in the land of reality, we don't have a perfect hood that will entirely contain all the dust spewed by these machines. We have a hood that captures a portion of the dust. If you can't contain all that dust, then you need to help make up for it and that's with a larger DC with properly sized ducting (not too big and not too small) with properly sized hoods.
At my DeWalt 12" SCMS, I have a full 1250cfm going to it via 7" pipe (airflow measured by me), yet I'm still not capturing all the dust. I've measured the air outside the shroud with a Dylos particle counter and it slowly gets worse and worse with each cut. Much, much better than not having the DC on though.
If I had smaller ducting with smaller ports, then the air quality would get worse much faster.
fyi, with my large cyclone and a 7" main duct, in one place in my shop I could flow about 1400cfm. Add on a 6" reducer and the airflow dropped to about 1300cfm. Add on a 5" reducer and the airflow dropped to just over 1000cfm. Add on a 4" reducer and the airflow dropped to 730-ish cfm.
Why would I want to kill airflow with a small port?
However, with my benchtop planer, using 6" flex hose to the tool and its factory 4" port, I could flow 725 cfm. With a shop made 6" port the airflow only went up to 779 cfm. Not much of an improvement. That's because the tool is so restrictive internally. There is not much makeup airflow inside the machine around that cutterhead.
Always remember that hood design is the most important thing. I'd rather have a 600cfm dust collector hooked up to a tablesaw with two 4" ports (cabinet and above table like a Shark or Excalibur) than 1000 cfm via a 6" port to the cabinet alone. The more efficient your hoods are at containing the spewing dust and directing it to the ducting, then the less airflow you'll need at the tool.
Cheers,
Allan
Allen, you just hit on the problem...
I do believe that Bill is on the right track, but his explainations are so detailed as to end up being plain and simple noise. Which leads me to wonder just how is the hobby woodworker supposed to deal with all they have to deal with in dust collection? Most of us aren't engineers... How do us mere mortals deal with this?
I mean honestly I would love a bucket of cash and to have Bill over on a consulting basis to set my system up... But that's just not going to happen in this lifetime unless I hit the lotto (hasn't happened yet...).
I hope I didn't come off as saying Bill is wrong, I don't think he is, I simply don't get it... I can only keep up with him so far before my head goes numb...
Even us engineers don't like too much detail sometimes... I like boiled down explanaitions a lot of times! Good thing for us, there's usually someone who LIKES reading the details, and is willing to do the boiling down for us!
I hear ya guys. That's why I've been trying to help out folks on the WOOD Mag DC forum. Testing how saw blades cut and explaining the info is very simple. Going over DC theory stuff where it's hard to see the results in your shop is much more difficult. Add on the fact each of us is different and reacts to wood dust in different manners just adds to the confusion. ???
A simple way to think of dust collection is like this:
A dust collector is simply an air mover. It moves dirty air at the tool through some pipe to the DC. Then this dirty air gets sorted into two areas, bigger bits in the dust bin and fine dust in the filters. Some tools are better at moving air and "sorting" the dust than others are. The more concerned you are about dust collection and respiratory health, the better performing DC you should buy.
For ducting, you want to help make your DC purchase work well. You don't want to hinder it. A DC can only move air well if the airflow isn't restricted. The more restrictive you make the path from the tool to the DC filter, the less air it will flow. That will mean more dust in your shop and in your lungs.
You will restrict airflow and lower performance by using too much pipe, too many elbows, too much flex hose, as well as using pipe that is too skinny. A poor filter that clogs easily is also a problem. All these things will reduce airflow, so you want to minimize them.
- Keep the runs short
- Use long radius elbows or two 45 deg elbows instead of a sharp 90 deg bend
- Reduce the amount of flex hose you use
- Use properly sized ducting
*** Using ducting that is too large can also cause problems. I'll skip the reasons for that at the moment.
I have a "duct size" ballpark rule of thumb that will give good performance for the majority of people out there with a modestly sized shop (2-car garage and smaller).
1HP DC = 4" ducting (really shouldn't use a duct network)
1.5HP DC = 5" ducting
2HP DC = 6" ducting
There are exceptions to this but I'll skip that for now.
Ideally, once you've decided on a duct size, you want to keep that size all the way from the tool to the DC. So if you want 6" pipe for a 2HP DC, you'll need to make sure your DC inlet is sized to match the pipe and you also want a new 6" hood for the tool.
Visualize that for a moment....lots of airflow moving from around the blade, carrying the dirty air though an unrestricted hood, through a short run of 6" ducting and then through the DC inlet, all the way to the dust bin and filter and finally back into the shop air.
You don't want 4" drops on a 2HP DC with a 6" main duct. It doesn't match. You've choked the airflow down and are losing performance. With some tools it won't matter because the tool itself is very restrictive internally and you can't move much air inside them. Benchtop planers are like this because there is hardly any space around the cutterhead. However, with tools like a CMS, TS, lathe, etc where you can have a large open hood, it can matter a lot.
Before I type a small novel, are we on the same page so far? 8)
Cheers,
Allan
So far so good...
But let's use for example, a layout like mine...
Dust Collector #1. Wet Dry vac / Thien cyclone setup.
Dust Collector #2. Reasonably stock HF 2HP 20amp DC fitted with Wynn filter and Thien cyclone setup.
Table saw, 3 ports, 1 @ 4" belly pan, 1 @ 2.5" blade shroud and 1 @ 2.5" blade guard (Shark Guard). The DC will pull from the belly pan and blade shroud. I have a shop vac setup to pull from the shark guard.
Band Saw. Will be adding a 4" port to the lower wheel guard, and adding a 2.5" port to the upper blade guide area to pick up what is spewing off the blade. This will be serviced from a 4x4x2.5 Y fitting.
CMS, Need a bettter hood, seen some plans out there but not sure what to do honestly...
Jointer. Benchtop with 2.5" port.
Planer. Bencthop with 2.5" port.
Oscillating sander. Bencthop with 2.5" port.
Sanders etc... 2.5" to reducers to the tool.
Drill Press. Need to add SOME sort of dust collection port.
Router table accessory. 2.5" port on top, need a lower port of some kind...
My Dust collector, and almost every single one like it I have seen including the Jet, Delta, etc... models I have seen at Rockler, all have 2 @ 4" to a single 5" fitting for intake.
As far as I know, 5" ducting is all but non existent.
From what I understand from Bill's articles, and I could stand to be corrected, hence why I posted the questions... Going with 6", and reducing down is a bad thing....
The impeller housing to inlet ring connection size is 5"...
My plan, such as it was, was to make a single straight run down the wall the DC is located against, for all the dust collection aside from the drill press, which would be gotten to via 2 @ 45 deg bends and across 6 feet.
I KNOW I want to keep flex hose to an absolute minimum, and completely eliminate any sharp bends.
So the question remains. Do I figure out a way to adapt the inlet of my DC to 6", and live with the restriction between the impeller and inlet ring, or do I go with 4"?
Sorry about all the questions. This is not exactly an easy topic to fully grasp, and it is quite important...
Quote from: dbhost on March 18, 2009, 08:51:19 AM
So far so good...
But let's use for example, a layout like mine...
Dust Collector #1. Wet Dry vac / Thien cyclone setup.
Dust Collector #2. Reasonably stock HF 2HP 20amp DC fitted with Wynn filter and Thien cyclone setup.
Sounds good....but we have a "problem" right away. The HF 2HP DC seems to have been designed by a marketing guy because its performance is nowhere near what a "normal" 2HP DC should be. The fan is way too small so in this case I'd stick with 5" pipe....at least until I can see one of these in person and do some testing. I live in Canada and HF isn't available here.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
My Dust collector, and almost every single one like it I have seen including the Jet, Delta, etc... models I have seen at Rockler, all have 2 @ 4" to a single 5" fitting for intake.
If you had a different brand of dust collector, I'd recommend replacing the factory metal blower inlet cover (most are removable) with a shop made plywood version with whatever sized flange you want to use the pipe size you want. Here's a pic of my friend's General International 2HP DC (very nice unit) and it came with a 2x 4" adapter on a 5" flange. It's now gone and he has a plywood version in its place with a PVC coupler screwed in so he can use 6" PVC pipe.
You can also see the factory blower cover being used to hold up the 6" PVC pipe during some airflow testing I was doing. That's all it's good for now. ;D
(http://i41.photobucket.com/albums/e254/allansouthsurrey/shop/IMG_3689.jpg)
Quote from: dbhost on March 18, 2009, 08:51:19 AM
As far as I know, 5" ducting is all but non existent.
It's only tough to find if you are looking for PVC. Your local BORG or a local HVAC distributor has a ton of 5" metal HVAC parts. Buy the heavier gauge stuff (26ga preferred) or buy 28ga spiral pipe (no need for 22ga spiral like some places recommend). Avoid 30ga stuff. You'll suck it flat. You can use HVAC elbows, wyes and reducers too.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
From what I understand from Bill's articles, and I could stand to be corrected, hence why I posted the questions... Going with 6", and reducing down is a bad thing....
The impeller housing to inlet ring connection size is 5"...
Yup. Reducing pipe diameter reduces airflow. It's as simple as that. However, there are times when you want to do that and that's when your DC isn't strong enough to move enough air through the pipes. You see, dirty air wants to move within a certain speed range though the pipes. Too fast and it'll have too much resistance and will reduce airflow. Too slow and the sawdust will fall out of suspension in the airstream and clogs may form. It's like Goldilocks....you want the ducting to not be too small or too large. You want it sized "just right". ;D
An example for your shop...suppose you had a 24 foot long run on the ceiling to get to a restrictive tool. I'd run 5" along the ceiling and 4" down to the tool. The reason for this is because with a restrictive tool, the airflow will be reduced. So 5" pipe would be too large going up the wall and sawdust would fall out of suspension and build up at floor level, making a clog over time. So I'd stick with 4" pipe to keep the velocity higher and carry that sawdust up to the ceiling. Then it can slow down a bit because the dirty air is moving horizontally and doesn't need to move as fast to get the sawdust to the DC.
...about that typical 5" flex hose joining the blower to the filter stand.... Want to see what my friends and I did to a friend's 2HP DC? Click this link and read the blog called "Project Hotrod - how to modify a 2HP DC to flow more air".
http://tinyurl.com/7ghmax
I will never let a little sheet metal get in the way of better performance. 8)
Quote from: dbhost on March 18, 2009, 08:51:19 AM
My plan, such as it was, was to make a single straight run down the wall the DC is located against, for all the dust collection aside from the drill press, which would be gotten to via 2 @ 45 deg bends and across 6 feet.
Ignoring the drill press for now, how long is that wall? Or are you saying the run to all the tools is only 6 feet long? Would you have the ducting run along the floor? 4' high? Ceiling?
Quote from: dbhost on March 18, 2009, 08:51:19 AM
So the question remains. Do I figure out a way to adapt the inlet of my DC to 6", and live with the restriction between the impeller and inlet ring, or do I go with 4"?
I'd do 5" pipe.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Table saw, 3 ports, 1 @ 4" belly pan, 1 @ 2.5" blade shroud and 1 @ 2.5" blade guard (Shark Guard). The DC will pull from the belly pan and blade shroud. I have a shop vac setup to pull from the shark guard.
I'd run 5" to the saw, then use a 5x5x5 wye with a 5x4 reducer for the belly pan and 5x3 (or 2.5) for the blade shroud. (I'd need to see the shroud)
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Band Saw. Will be adding a 4" port to the lower wheel guard, and adding a 2.5" port to the upper blade guide area to pick up what is spewing off the blade. This will be serviced from a 4x4x2.5 Y fitting.
I'd run 5" to the BS, use a 5x5x5 wye with a 5x4 reducer for the door and another 5x4 reducer for a custom made under table port. I just finished making my bandsaw DC hookup and here's a pic. I used 5" for the under table port because I have a large DC.
(http://i41.photobucket.com/albums/e254/allansouthsurrey/shop/IMG_3761.jpg)
Quote from: dbhost on March 18, 2009, 08:51:19 AM
CMS, Need a bettter hood, seen some plans out there but not sure what to do honestly...
Lots of styles to choose from, but most revolve around a large shroud covering the rear portion of the saw from the fence back. Run 5" pipe to here and use a big port behind the saw. I use HVAC parts for hoods like floor register pieces. Cheap and saves a bunch of time. Look at my blog again and read the one about making new hoods for some ideas. I should probably add my SCMS and BS there now.
http://tinyurl.com/7ghmax
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Jointer. Benchtop with 2.5" port.
Planer. Bencthop with 2.5" port.
Oscillating sander. Bencthop with 2.5" port.
Sanders etc... 2.5" to reducers to the tool.
Use your shop vac with these but use a good filter. I use a HEPA filter in my shop vac. Those tools you listed are very restrictive and a big DC doesn't like to move air through tiny ports. 4" minimum is my rule of thumb.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Drill Press. Need to add SOME sort of dust collection port.
A shop vac is good here or 4" hose from a DC. Anything larger becomes unwieldy.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Router table accessory. 2.5" port on top, need a lower port of some kind...
Back to the DC. Run 5" pipe, 5x5x5 wye with 5x3 and 5x4 reducers, 3" to the fence and 4" to the cabinet. There is a chance you might get better performance by using your shop vac at the fence port.
Quote from: dbhost on March 18, 2009, 08:51:19 AM
Sorry about all the questions. This is not exactly an easy topic to fully grasp, and it is quite important...
No problem.
Cheers,
Allan
I should have explained the TS here. I keep forgetting this isn't BT3Central...
I have a Ryobi BT3100 table saw with the router table wing and accessory kit that I modded to get a GREATLY improved fence. The factory ports on the blade shroud and router fence are 2.5". I have no clue how to hook up a different fence port since the router fence is based on the TS fence...
The saw. (Sorry, no pics of the shroud,)
(http://inlinethumb23.webshots.com/44374/2531294620103915817S600x600Q85.jpg) (http://home-and-garden.webshots.com/photo/2531294620103915817ZNYDIs)
The router fence setup.
(http://inlinethumb17.webshots.com/24656/2619091060103915817S600x600Q85.jpg) (http://home-and-garden.webshots.com/photo/2619091060103915817ESBUGD)
Adapting to 6" S&D is NOT out of the question with the current 2HP HF DC... The older model, with the 14 amp motor / smaller impeller is reported to be a bit weak, the current model though, has a much stronger 20 amp motor, and a larger, I believe 11.5" impeller. (I may have read that wrong, and I haven't measured it myself).
I have seen at least 3 of these converted like your friends General International DC. I am / have considered it, but debate the usefulness of 6" in my small shop.
The DC plumbing will be run along the ceilling, down an 18' wall, and accross to meet up with the drill press. I believe tools needing the dust collector will be the table saw, the band saw, the compound miter saw, the drill press, and eventually a lathe. I am sure the Ridgid OSS could use improved dust collection, but how?
For your table saw... With a shark guard and blade shroud, are you really getting much, if any, dust from the belly pan? You could put a plast gate inline with the bely pan split and manipulate the flow. Partially close it, and get more suck thru the blade and shark?
Not sure... Haven't tried hooking up the shroud / shark and not the belly pan. The ports are there, I figured I'd use them...
Ahhh...thanks for the pics. It looks like the router table fence might be best served with a shop vac. Tiny ports = shop vac.
Thanks for the info about the revised HF 2HP DC. If you get bored one day can you please remove the blower cover and measure the fan for me? I'm curious how much this has grown. Ideally, a 2HP DC would have a 12" fan so I'll keep my fingers crossed for you.
Too bad you didn't get the shark guard with a 4" port. I've tested that one and compared it to my Excalibur and it performs very well. Maybe it works just as well with a shop vac?
I have the Ridgid OSS so I know what you mean. Right now I use my shop vac with it. I'm hoping to build a custom hood for it, especially when I use the belt sanding attachment. I'd use the factory port in addition to a hood at the side of the belt sander. I'm debating a movable one for the spindle sander too. If it can move easily and be suspended in the air, then maybe it can go above the spindle if you are sanding inside a shape.
The big tools requiring a DC rather than a shop vac would always benefit from larger ducting. 4" just doesn't cut it, except for the drill press.
Cheers,
Allan
Quote from: AllanJ on March 21, 2009, 01:35:19 AM
Ahhh...thanks for the pics. It looks like the router table fence might be best served with a shop vac. Tiny ports = shop vac.
My router table fence has a small port too, but I have the DC split with a 4" Y, then it necks down to 3" PVC to the cabinet, and down to the 2.5" hose to the fence. IT sucks REALLY well from the fence I have to say. Maybe reducing the entire DC flow down to 2.5" would be bad, but dividing it up then reducing it seems to work well.
Well,
Since I have the hose, blast gates, and fittings, only thing I am missing is the pipe, and honestly, getting everything in 6" would be a pure and simple PITA at this stage, the system, at least for now, is going together with 4" S&D pipe...
FWIW, this is a temporary setup at best. I am working on permitting and budget considerations for a new 12x16 gambrel roof barn / shed for a workshop. Yeah I know, not the biggest footprint, maybe not even big enough, but as big as I can go on my lot. Depending on air quality readings with the 4", I may go to 6" in the new shop... So in the space of about 2 years, I may be selling some 4" self cleaning blast gates, some 4" to 2.5" wyes, and a fist full of clamps...
I hear ya. ;)
Like most things, something is definitely better than nothing. I ordered a Dylos particle counter so one of these days I'll try some tests to see what the difference may be in a situation like yours. I'm curious. ;D
Cheers,
Allan
I am doing what I can to maximize air flow. I wish money and time weren't the rare commodities that they are...
Bill does have some very valid points though that pretty much most tool dust collection ports need a LOT of improvement...
I can say that the high static lift of the shop vac setup does work well on top of the saw / router table. But below is a different story... Too big of a space involved LOTS of air needs to be moved to replace the lots of air that gets quickly filled with dust...
Where possible, I want to keep flexible hose to less than 2.5', but I know that won't always be possible...
So I continue with the odyssey and plod forward...
With the pending shed / workshop layout, I will likely START off with 4", but I found a company called KenCraft that seems to offer 5" DC ducting and fittings. Lee Valley has 5" blast gates, now I just need to find 5" hose, and a way to connect that to the tools / improve the dust hoods there and I think I am good...
Just like the shop, the dust collection is a work in progress...
Quote from: dbhost on March 30, 2009, 02:17:06 PM
I am doing what I can to maximize air flow. I wish money and time weren't the rare commodities that they are...
You and me both!
Quote from: dbhost on March 30, 2009, 02:17:06 PM
I can say that the high static lift of the shop vac setup does work well on top of the saw / router table. But below is a different story... Too big of a space involved LOTS of air needs to be moved to replace the lots of air that gets quickly filled with dust...
That's a good way to look at it. Big space requires a big DC. Small space requires a shop vac.
Quote from: dbhost on March 30, 2009, 02:17:06 PM
Where possible, I want to keep flexible hose to less than 2.5', but I know that won't always be possible...
Yes, keep the hose short, but don't mess up your shop because of it. Woodworking is a hobby for most of us and a hobby should be fun. It shouldn't be a PITA. Do what you need to in order to reduce the length and turns in your ducting, but don't piss yourself off because of it. It's all about balance.
Quote from: dbhost on March 30, 2009, 02:17:06 PM
With the pending shed / workshop layout, I will likely START off with 4", but I found a company called KenCraft that seems to offer 5" DC ducting and fittings. Lee Valley has 5" blast gates, now I just need to find 5" hose, and a way to connect that to the tools / improve the dust hoods there and I think I am good...
Just like the shop, the dust collection is a work in progress...
You can make your own blast gates too. ;) I made my own 7" blast gates. Lee Valley sells 5" flex hose, same with Grizzly. Three local woodworking stores within 40 mins from me sell 5" hose too. If you live near a big city, it's probably available right there. I use HVAC fittings (elbows, reducers, wyes) available at Home Depot and seal all the seams. Sure there are better parts available elsewhere but I'm not interested in mail ordering expensive parts. Sizing the duct diameter properly and using crummy HVAC parts will flow way more air than 1" smaller diameter pipe with fancy welded long radius elbows, extra long tapered reducers and nicely flowing wye branches.
For hoods, I'll remind you about my blog on Wood Magazine's site about making new hoods utilizing HVAC parts. They are a major time saver and are really cheap at a few bucks each...and it's kinda fun to find a close-fitting HVAC part and make it work. ;D
http://tinyurl.com/cjwa9f
Good luck with this!
Cheers,
Allan
Yeah. I am very happy with the shop vac system, mostly. It works GREAT on the planer (Ryobi AP1301), jointer (Sunhill SM-150B), and did work as well as anything could on my old Ryobi BTS-21 table saw... It also works exceedingly well with handheld sanders. Where it falls flat is with my Ridgid OSS, 14" band saw, and table saw. We aren't even going to talk about the drill press... I will check your blog later. Maybe you have some ideas how to collect the dust off my Ridgid OSS that actually, oh I dunno, works...
I agree with you about the balance thing. I am an unrepentant cheapskate and tinkerer. I am actually having fun fooling with this setup. I am aware there are some of my locations that need more flex line than that.
Not sure I am quite willing to make my own blast gates when the Lee Valley self cleaning ones are quite affordable. While not as cheap as a DIY approach, this is one of those what is your time worth issues... I was not aware they had 5" flex hose...
Are there any special things to consider when using HVAC ducting?
Just curious. I have seen more than a couple of guys upsize to 6" on the HF 2HP DC inlet before the impeller. Won't the 5" between the impeller and the inlet ring be a problem with that setup?
I fully agree with Alan and a few others here.
Yes, my web pages grew from incorporating well meaning help from simple without explanations to so complex I can?t even find things. To make repair I am doing another rewrite to separate off the cream and move the technical into its own areas.
Also, as Alan shared, the CFM numbers I advocate remain the industry standard which our small shop vendors continue to ignore. Not me, but instead the top commercial dust collection firms that guarantee their customer air quality built the following table. This table includes more than twenty years of refinement to set the minimum airflow we need at each tool for each different level of dust collection.
(http://billpentz.com/woodworking/cyclone/images/CFMRequirementsTableSmAAF.gif)
Also Alan was correct with his summary about blower horsepower and air moved and he accurately touched on the major problem with our small shop vendors. These ?bendors? remain trapped in an exaggeration game they created and now don?t know how to escape with their often just plain fictitious CFM and filtering claims. Based on tests that dozens of us did all over the country, most vendors advertize maximum airflow that is roughly double what their systems provide in real use. Many, especially vacuum vendors exaggerate maximum horsepower when the reality is none provide more than about 1.5 hp when connected to a 120 V outlet.
Alan also touched on our biggest problem in getting good fine dust collection today. Almost all small shop dust collector and cyclone filtering claims are badly exaggerated. Our tests found all mainstream small shop dust collector and cyclone makers freely passed ten to twenty times larger particles than claimed on their ads. Their rationale is they use outdoor testing versus indoor which requires testing the filters when clean and new. The result is the fine filters we buy to protect our health leave a clean looking shop while freely passing the fine invisible unhealthiest dust particles sized 10-microns and smaller. Worse, these filters become dust stores so every time we turn on our dust collector or cyclone they blow dangerously unhealthy amounts of fine invisible dust all over our shops.
You would not believe the numbers of people who have bought http://www.DylosProducts.com (http://www.dylosproducts.com) Dylos 0.5 and other air quality meters that found their expensive top magazine rated dust collectors and cyclones made their shop air outright dangerous. Additionally, you would not believe the hundreds who have written over this past nine years who said they had no problem with wood dust, then suddenly they ended up getting ill, some with life threatening problems. Folks, many woods are sensitizer so just like me you can go for decades with no problem the suddenly find yourself with a minor problem up to being rushed to the hospital.
Let me summarize all the physics, engineering and medical concerns together. The only way to avoid the fine dust is not to breathe it. You can work outside, collect the fine dust as it is made or use a strong fan blows that dust away from us as it is made then out of our shop. Air cleaners are great to help with finishing, but they work so slowly we end up with our lungs doing the filtering. To collect the dust at the source we either need tools that totally trap the dust or the airflows shown in the above table plus upgraded hoods and tool ports. For tools with un-modifiable 2.25? ports always use a big shop vacuum with fine filter. To move the air we need for good fine dust collection either use an oversized blower with smaller pipe or an appropriate sized blower and the right size pipe. For my cyclone solutions I do a little of both because we really should be using 7? diameter pipe for 1000 CFM, but I recommend 6? diameter pipe and compensate by using an oversized blower wheel to increase pressure and duct air speed. This lets me move the real 1000 CFM that our table shows we need at most larger tools with all 6? duct. To move this much air in an average shop with ducting and a good set of fine filters such as the MERV-15?s I get from Wynn Environmental http://www.wynnenv.com/cartridge_filters.htm (http://www.wynnenv.com/cartridge_filters.htm) we need at least a 3 hp dust collector turning a 14? diameter impeller or 3.5 hp cyclone turning a 15? diameter impeller. That is pretty much it in a nut shell except you still need to address your tool ports and hoods.
Bill...
Okay so for example, for those of us cheap skates here that went with the cheapo HF 2HP DC (yeah right I know overrated but it is what it is..) and Wynn 35A cartridge (your recommendation) how are we to get the 5" port, and connection hose between the impeller housing and inlet ring to play nice with 6" (or bigger) duct?
I quote your Cartridge Conversion page subsection G...http://www.billpentz.com/woodworking/cyclone/DCConversion.cfm (http://www.billpentz.com/woodworking/cyclone/DCConversion.cfm)
"They make this filter in the same paper poly blend that most other makers offer, and offer it in the far superior all poly version."
And I in turn quote from the Wynn Environmental product description page for the 35A cartridge kit.
"99.995% efficient at 1.0 micron and above"
You recommend .5 micron filtration, yet you tout the 1 micron spun bond poly as being far superior. Why is that?
And YES I understand you state that as a lesser solution, but if it is what we have to work with.
I'm mostly trying to get my head around this. You do recommend the 6" pipe pretty clearly in your writings, so I am just itching to figure out how that works when not all, but most single stage dust collectors use 5" fittings like the Central Machinery does... Is necking the port down from 6" to 5" at the DC an option? If not then how does that work? On most of these machines, you CAN make a custom flange to go into the impeller housing, but it would require a LOT of sheet metal work to adapt the inlet ring and outlet of the impeller housing to accept 6" hose...
And with a great quantity of woodworking equipment being fitted with 2.5" ports injection molded in to fragile plastic housings, it would seem to be a less than simple matter to upgrade those to 6" duct.
dbhost...
Okay so for example, for those of us cheap skates here that went with the cheapo HF 2HP DC (yeah right I know overrated but it is what it is..) and Wynn 35A cartridge (your recommendation) how are we to get the 5" port, and connection hose between the impeller housing and inlet ring to play nice with 6" (or bigger) duct? You don?t, the HF only has ample capacity to support 5? duct.
I quote your Cartridge Conversion page subsection G...http://www.billpentz.com/woodworking/cyclone/DCConversion.cfm
"They make this filter in the same paper poly blend that most other makers offer, and offer it in the far superior all poly version."
And I in turn quote from the Wynn Environmental product description page for the 35A cartridge kit.
"99.995% efficient at 1.0 micron and above" So step up to the newer Wynn MERV 15 filter and get your real 0.5-micron filtering.
You recommend .5 micron filtration, yet you tout the 1 micron spun bond poly as being far superior. Why is that? Let?s discuss apples and oranges separately:
1. I recommend spun bond poly filters over paper poly blends because the spun bond lasts four times longer, can be washed, and for the same CFM requires half the overall filter area. They cost twice as much but are worth it.
2. In terms of filtering level the EPA, European Union, and medical experts all consistently recommend HEPA level filtering for dust control. HEPA is the old radiation breathing mask standard where every single filter is individually tested and certified as 99.9% efficient on particles sized 0.3 microns and larger. When I first put up my web pages only one vendor, Donaldson Torit, offered a fine woodworking filter, their 0.5-micron filters. All other affordable filters were 1-micron. Since then manufacturing efficiencies have improved and we can now get good 0.5-micron filters for about what I had to pay for poly blended filters ten years ago. Today I personally use on my Jet DC a single and on my cyclone a set of the Wynn Environmental MERV-15 rated filters.
And YES I understand you state that as a lesser solution, but if it is what we have to work with. I tire of hearing this same argument. For decades I used a ceiling mounted air cleaner, nice set of dust collectors, and a large doorway fan that kept my shop well ventilated and often too hot or cold to enjoy. I saved diligently and finally bought the top magazine rated cyclone system with vendor designed and supplied ducting plus vendor recommended filter upgrade. Less than a month later I found myself rushed to the hospital with an apparent heart attack. That cyclone created a bad false sense of security because it left a clean looking shop while building up dangerously high invisible dust levels. Three months after I went to the hospital an air quality test showed my shop and home badly contaminated. Worse, that cyclone was a dust store as just turning it on with no woodworking pushed the fine invisible dust level over 10,000 times higher than the maximum airborne invisible dust that EPA considers safe. Because I worked many toxic woods the considerable invisible dust that built in my clean looking shop and home caused me to rapidly sensitize with a bad allergic reaction. My Cyclone and Dust Collection Research web pages and dust collection efforts are dedicated to try and help others avoid this same problem. I would gladly pay ten times what I spent on that expensive POS cyclone with ducting and fine filter to have not had to live on an oxygen hose for the last ten years. So you will never convince me that compromise on our dust collection is wise.
I'm mostly trying to get my head around this. You do recommend the 6" pipe pretty clearly in your writings, Yes, you need 7? duct to move the 1000 CFM or 6? duct and oversized blower wheel. so I am just itching to figure out how that works when not all, but most single stage dust collectors use 5" fittings like the Central Machinery does... Is necking the port down from 6" to 5" at the DC an option? If not then how does that work? On most of these machines, you CAN make a custom flange to go into the impeller housing, but it would require a LOT of sheet metal work to adapt the inlet ring and outlet of the impeller housing to accept 6" hose... Although it is an easy fix to install a 6? flange on the face of the HF blower, upgrading a HF to 6? pipe is a waste of time and money. That blower and impeller do not move ample air to support 6? duct, so you will end up with clogging in the vertical runs and piles in the horizontal runs unless you use minimum duct and keep very clean open filters.
And with a great quantity of woodworking equipment being fitted with 2.5" ports injection molded in to fragile plastic housings, it would seem to be a less than simple matter to upgrade those to 6" duct. Agreed, I quit buying tools from makers who continue to give us 2.5? diameter ports on machines that need up to 1000 CFM for good fine dust collection. For those tools that I already own and use these small ports I forget my DC and instead use a good shop vacuum. An okay shop vacuum pulls about 50? of working vacuum versus a HF dust collector at about 5?. My high end shop vacuum pulls over 100". That ten to twenty fold difference in pressure is the only way to get good chip collection from tools with these tiny ports. To get them to also have good fine dust collection you need to use in addition to your vacuum a hood going to your dust collector which pulls in as much air as possible from around the working area of your tool.
Quote from: Bill Pentz on November 02, 2009, 07:11:54 PM
I tire of hearing this same argument. For decades I used a ceiling mounted air cleaner, nice set of dust collectors, and a large doorway fan that kept my shop well ventilated and often too hot or cold to enjoy. I saved diligently and finally bought the top magazine rated cyclone system with vendor designed and supplied ducting plus vendor recommended filter upgrade. Less than a month later I found myself rushed to the hospital with an apparent heart attack. That cyclone created a bad false sense of security because it left a clean looking shop while building up dangerously high invisible dust levels. Three months after I went to the hospital an air quality test showed my shop and home badly contaminated.
Oh common, that is B.S. Unless you had a hole in your filter stage, no such thing was happening. Anyone with a Dylos meter can tell you those types of assertions are bogus.
And there is no way your shop/home air quality was "contaminated" three months after running any machines. That is preposterous.
Quote from: Bill Pentz on November 02, 2009, 07:11:54 PM
I'm mostly trying to get my head around this. You do recommend the 6" pipe pretty clearly in your writings, Yes, you need 7? duct to move the 1000 CFM or 6? duct and oversized blower wheel. so I am just itching to figure out how that works when not all, but most single stage dust collectors use 5" fittings like the Central Machinery does... Is necking the port down from 6" to 5" at the DC an option? If not then how does that work? On most of these machines, you CAN make a custom flange to go into the impeller housing, but it would require a LOT of sheet metal work to adapt the inlet ring and outlet of the impeller housing to accept 6" hose... Although it is an easy fix to install a 6? flange on the face of the HF blower, upgrading a HF to 6? pipe is a waste of time and money. That blower and impeller do not move ample air to support 6? duct, so you will end up with clogging in the vertical runs and piles in the horizontal runs unless you use minimum duct and keep very clean open filters.
This begs the inevitable question then. If, in your opinion, after all of the research you have done, the HF DC and similar models are not workable dust collection solutions, why list them at all in your writings other than to say DO NOT DO THIS?
Your assertions on pleated filtration versus a simple bag are certainly based on solid, well established engineering principles (Look at an automotive air filter for an example of using pleated media to expand the amount of surface area available to filter through, thus increasing air flow for a given filtration level).
A cursory Googling of duct size / cfm charts shows a WIDE array of highly conflicting data. Most of this data is aimed at negligible static lift systems (HVAC) and nearly useless, there are the charts you seem to quote, and other charts showing, well vastly different data. Going back to the automobile analogy, while I am certain the amount of static lift has to be somewhat higher, typical carburetor fitted big block V-8 engines were frequently fitted with 650 to 850 CFM 4BBL carburetors, which pulled air through an enclosed can type air cleaner housing with an approximately 3" intake hole for fresh air. From a "Feel of the hand" perspective, a Pontiac 455 CID V-8 Holley 750CFM 4BBL intake pulls with a perceptably lower feeling of suction than my Harbor Freight 2HP Dust collector. This is however a mere pereception issue, and has no basis is scientific method or measurement.
This leaves us to ponder, what setups were tested, and were air quality samples taken before / after the dust collection system was run, and before / after dust producing events took place?
If you really want to know the CFM of your system at the dust ports, contact your friendly neighborhood HVAC person that has an air velocity gauge (or google to find how to DIY a pitot tube like used in airplanes to measure air speed).
The air velocity gauge will tell you the speed of the air in feet per minute. Here is the basic math: given you have the feet per minute (FPM) now multiply that times the cross sectional area you are pulling the air from (change it from square inches of cross section to square feet by dividing by 144). So a 6" pipe is 29.27 sq inches or .196 sq feet. So to get 1000 CFM you need an air velocity of 1000/0.196 = 5093 feet per minute in air velocity. That is almost a mile a minute or 60 MPH (88 KPH).
So if you have a 6" duct, if you don't have 5093FPM, or about a 60MPH breeze, you don't have 1000CFM.
And for some popular ducts to give 1000CFM:
| Duct Size | Feet Per Minute | Or roughly Miles Per Hour |
| 2.5" | 29,333 FPM | 333 MPH |
| 4" | 11,459 FPM | 130 MPH |
| 6" | 5093 FPM | 57.8 MPH |
| 7" | 3742 FPM | 42.5 MPH |
So the size of motor/impeller/duct(diameter, length, curves, and smoothness inside) combination you use still needs those air speeds applied at the tools to fulfill the air quality needs. I think it is easy to see why a good system requires big motors! And why using to much flex tubing will cause lots of friction in the air especially if there is much of it at lower sizes.
Now in defense of Bill... He is addressing what it takes to keep us healthy. He has been effected by poor dust management in his own shop and this is what he has come up with to keep him healthy. ... If you are superman, well, this may not apply to you. ... All of us must make our own choices.
In short,
more air removed from the work area, the fewer fine particles you will breath in.
If you must recycle the collected air back into the shop, you need to filter it. A poor filter will let the 'bad stuff' on through, and to small a filter will clog a lot faster. In what I see in Bills documents, chip collection is a good thing (and helps keep the filters clean) but secondary to keeping the fine particles picked out of our breathing space.
Bill has made his decision for him, and is just trying to let us know what he has found to be reasonable solutions in his eyes.
On duct work, not all HVAC type ducting will stand up to the vacuum pressure that a good dust collection system will generate. If you close all the 'blast gates' it can starve the blower and the low pressure will cause the air to collapse the ducts.
If I am wrong, please correct me. This discussion is to help us all.
Quote from: dbhost on November 03, 2009, 12:12:00 PM
Quote from: Bill Pentz on November 02, 2009, 07:11:54 PM
I'm mostly trying to get my head around this. You do recommend the 6" pipe pretty clearly in your writings, Yes, you need 7? duct to move the 1000 CFM or 6? duct and oversized blower wheel. so I am just itching to figure out how that works when not all, but most single stage dust collectors use 5" fittings like the Central Machinery does... Is necking the port down from 6" to 5" at the DC an option? If not then how does that work? On most of these machines, you CAN make a custom flange to go into the impeller housing, but it would require a LOT of sheet metal work to adapt the inlet ring and outlet of the impeller housing to accept 6" hose... Although it is an easy fix to install a 6? flange on the face of the HF blower, upgrading a HF to 6? pipe is a waste of time and money. That blower and impeller do not move ample air to support 6? duct, so you will end up with clogging in the vertical runs and piles in the horizontal runs unless you use minimum duct and keep very clean open filters.
This begs the inevitable question then. If, in your opinion, after all of the research you have done, the HF DC and similar models are not workable dust collection solutions, why list them at all in your writings other than to say DO NOT DO THIS?
Your assertions on pleated filtration versus a simple bag are certainly based on solid, well established engineering principles (Look at an automotive air filter for an example of using pleated media to expand the amount of surface area available to filter through, thus increasing air flow for a given filtration level).
A cursory Googling of duct size / cfm charts shows a WIDE array of highly conflicting data. Most of this data is aimed at negligible static lift systems (HVAC) and nearly useless, there are the charts you seem to quote, and other charts showing, well vastly different data. Going back to the automobile analogy, while I am certain the amount of static lift has to be somewhat higher, typical carburetor fitted big block V-8 engines were frequently fitted with 650 to 850 CFM 4BBL carburetors, which pulled air through an enclosed can type air cleaner housing with an approximately 3" intake hole for fresh air. From a "Feel of the hand" perspective, a Pontiac 455 CID V-8 Holley 750CFM 4BBL intake pulls with a perceptably lower feeling of suction than my Harbor Freight 2HP Dust collector. This is however a mere pereception issue, and has no basis is scientific method or measurement.
This leaves us to ponder, what setups were tested, and were air quality samples taken before / after the dust collection system was run, and before / after dust producing events took place?
I am not qualified to answer most of what you said, however, I can take a stab at the carb analogy and it is exactly what Bill was saying about the shop vac vs. the DC when it comes to 2.5" dust ports. A car engine has a surprising amount of negative pressure when it is in the intake phase. If I remember my HS auto shop class, its something in the high 20's" (28" comes to mind) of mercury class which is far more than a shop vac. Therefore, the suction of a car engine alone can provide the CFM through such a small opening, not to mention particle size, don't forget when you are running a dust collector you are not only pulling in the finest materials but also the coarse materials. The finest materials maybe finer than an air-fuel mixture, however, mixed into that is the coarser particles that are certainly larger than the air-fuel mixture of an auto engine and its because of this that you need the larger ductwork and ports to reduce the friction developed in the larger particles that slow down the airflow and ultimately slows down the fine particulates so that they escape and are not captured by the DC.
At least that is how I see what Bill is saying and has been saying on his web site for years.
Paul