J. Phil Thien's Projects

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

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

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: 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

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.

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 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

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