DC Thien lid question and best bandsaw dust extract setup..

[Tim Rinehart]

Hugh Jardon and Cory Hoehn...thanks! Reference original thread... http://www.sawmillcreek.org/showthread.php?t=137002

Gotta thank both of you for the inspiration here. I picked up a HF DC a week ago, and decided to modify with the trash can and Thien lid.

Overall, very happy with how it looks, but now I have the chore of getting ducting run.

I used 4" Sch 40 PVC elbow as entrance into Thien lid, which has some constriction over the normal 5" inlet this DC is setup with. I have a piece of 4" PVC connector (about a 4.5" ID) that I was able to turn down to accept the flex hose quite nicely between the lid and the DC inlet.

Now, I've got about 20' for my longest run (to my lathe and bandsaw) for pickup of dust. I'll NEVER run more than one of these at a time, so...I'm debating between 4" Sch 40 pipe and fittings from HD, vs 5" spiral pipe and fittings from Rockler.

If I have any confidence in making the 20' run with 4" PVC... I'll probably stay that way, but also wasn't sure if my inlet conditions (the 4" PVC elbow in Thien lid) already killed any advantage to running 5" pipe. I don't think it did...but don't have any real experience to base it on. I think regardless, the 5" run will reduce losses I'd otherwise get with 4"...but not sure if 5" would be overkill for 20' run in this case.

Q1: Do I need more than 4" with this DC and my usage?

Next, on my Thien lid, I've seen where some pics (incl Phil's) don't show any stub coming down from the connection to the inlet of the DC, and I don't have one either...but some (like Corey's) show a stub.

Q2: Should there be a stub for the Thien lid to work as expected?

Lastly, I've run my shop vac when using Jet 12" bandsaw and still get ALOT of dust around sides, front, back...you name it.

Q3:what is best anyone has come up with for dust extraction beyond the single 2" port on a 12" BS (mine is a Jet 12", but I think most like the Jet 12" are similar in dust extraction port design).

Thanks for your input, as always.

[David Hostetler]

Tim,

If Bill Pentz is right, and chances are he is, perhaps a bit overkill, but overkill in the right direction, you really ought to be using 5" ducting.

Specifically, if you can you should...

#1. Replace the Thien lid with one with a 5" piece of spiral pipe in the center for the outlet to the DC.
#2. Cut a side inlet / spiral pipe 5" fitting into the trash can. (See Phil Thien's site for this, there are lots of posts there...).
#3. Run with 5" spiral / similar pipe run with self cleaning blast gates...

There are other options. Not necessarily Bill Pentz approved...
#1. Use 6" duct and fittings, and "upfit" your impeller cover to a shop made one with a 6" port. Folks are doing this and reporting excellent results. I believe this is not a Bill Pentz approved approach...
#2. Use a 5" to 4" reducer between your impeller and Thien cyclone, and just run the 4" like you are talking about. I am using a similar approach (right now I am using a single 20' hose to go tool to tool, my ducting is going to be 4" because it is what I have...). Again, lots of folks are doing this with good results. I am sure Bill Pentz doesn't approve, but it gets results...

If I had nothing but money to run 5" spiral pipe, I wouldn't be messing with a HF dust collector in the first place... The 6" upfit is a good option, and what I will likely do in the future, but for now, and a long time to come, I will only be using 4". My machines are fitted for it, and upsizing everything to 6" would be more hassle than it is worth...

You may want to double check your lid to baffle alignment. As I understand the Thien baffle, the intake elbow is supposed to be lined up so it comes in just as the baffle 120 deg larger portion starts, yours seems to start in the middle...

[Rod Sheridan]

Tim, 4" is certainly too small for a system, it's even too small for many of the individual machines that come fitted with 4" ports.

If you start with a table saw, my present machine requires 475CFM at the cabinet, with 160CFM at the blade guard, for a total of 635CFM. That's almost twice what a 4" duct can supply. (My saw has a 120mm port, about 5", plus a 50mm port on the guard).

My jointer/planer require about 500CFM also, too much for 4" pipe once again.

You would be best laying out your shop on paper, determining the CFM's required, then doing the static pressure loss calculations to size your ducting.

Regards, Rod.

[Joe A Faulkner]

You might consider searching the net for the Thein Discussion Forum. Once you find that site, checkout a post titled:
Trash Can Topper Project with 6" Ports by vawoodworker84.

You might also look for posts there and here from Greg McCallister. On the Thein Forum look for the title: My version w/6" duct or here at:
http://www.sawmillcreek.org/showthread.php?t=97825.

You may want to consider 6" pipe for the entire system. Of course you would need to build a new "hat box" for your trash can.

[Cory Hoehn]

Nice work, Tim! Why plumb the entire shop if you've got that spiffy DC on wheels? Wouldn't it be just as easy (and probably much more efficient) to move the short hose from tool to tool? That's what I've been doing with mine and it works great.

I think for the amount of duct work you're going to put in, you'll need a bigger DC to get "proper" CFM to all your machines. That having been said, the HFDC will suck up most of anything you'll throw at it.

Good luck.

Cory

[Ben Bonif]

Kinda in agreement with Cory or in my case I am. Hate the cobwebs of ducting on lower ceilings and won't ever again give up my wall space so a clean wheel setup hold massive amount of appeal to me. I'd feel different in a huge shop or such I'm sure but in small shop setting -if room to roam allows-wheel it to central location and be done

[Tim Rinehart]

Thanks to everyone for the comments. I went to Phil's site and read thru the referenced articles on larger inlets and such. Wow, ALOT of material on this.

Regardless of adequate duct sizing, I did realize my lid doesn't have enough breathing room between the elbow and baffle/lid to help prevent accumulation of debris, and that I needed the stub coming down from the outlet. I'm kinda curious as to the effect of not running with the stub in place. Unless it somehow helps the swirl and drop of chips...wouldn't it not being there provide a more difficult environment for chips to get sucked up? I'll have to perhaps experiment with effect, with/without the stub piece.

I see my primary use of this to be for sanding when at my lathe...and I like the idea of it being 20 feet away, in a corner, and perhaps with some sound deadening added back there so I can comfortably listen to the radio while working in my shop. I think I'd use it more that way, vs pulling it around obstacles like table saw, grinder, etc.

It's proximity to my table saw is such that it will likely require only a short length of flex...which could double as the same route for a portable planer and other items that can roll TO the area of the DC and table saw.

Maybe the best route initially, is to just run a length of 4" PVC directly to my lathe (bandsaw there too), a small length of flex, and see how it goes with minimal investment in materials. If I go the larger duct route...I think a 5" or 6" side entry looks to be a good workable solution.

Thanks again to everyone for comments/suggestions.