help with hose and fitting size for shop vac Thien sep

[Guillemot]

Hi All,

I've been reading over this forum for the last month and have finally decided to jump in and build myself a Thien separator. They just look awesome, and I'm drowning in sawdust.

I plan to run it on my Rigid 12 gallon shop vac (comes with 2.5" hose) on a 30 gal trash can.

What size dust collection hose and fittings would you all recommend for this setup on the tool side of the separator? The "here's the plans" posting suggests 4", but this seems too large for a shop vac setup.

Maybe 3" from the tool to the separator (with 10' of 3" vacuum hose and 3" fittings) and reduce to 2.5" from separator to vacuum? Seem reasonable?

Thanks for providing so much great information.

Jeff

edited to correct vacuum size (i incorrectly said 5 gal initially)

[phil (admin)]

Yep, what Chuck says.  If you go w/ a 30-gallon can, you may find it collapsing if you ever block the inlet of the hose.

If you want the capacity, try to find a 30-gallon DRUM.  They're much stronger than garbage cans.

[Peter]

It is indeed possible to collapse a 30-gallon can with a Shop Vac. I did it. Twice. The second time, the walls of the can touched. But I had already built the seperator and I wasn't very interested in buying a new can...so I pushed the can back into shape and added external stiffeners to strengthen it. I used some scrap 3/4" plywood to make two rings around the can, dividing its height into thirds, and put a #6 x 1/2" screw in each rib of the can. I didn't seal the screws. There is so much leakage now, that I doubt the can would collapse even without the ribs. But I have noticed that the vac no longer picks up heavier objects, such as screws, nails, etc. This is mostly okay by me--I really just want to remove sawdust from the shop. I suppose that if I sealed all those screws, it might suck up screws.

Here's a photo:


But as it is, it gets all the dust! And almost none goes into the Vac--just the talcum-powder-fines.

[footprintsinconc]

peter, you can just put a bead of caulking above and below the plywood rings and you wont have that leak issue anymore.

[dbhost]

For 2.5" equipped shop vacs, use 2.5" hose, for 4" equipped dust collectors, use 4" hose...

[dbhost]

FWIW, On my 20 gallon trash can separator, I used Peachtree #387 2 1/2" Router Table / Bandsaw Dust Ports and 2.5" schedule 40 pipe nipple, and street elbow from Ace Hardware.

I believe Rockler and Woodcraft both also offer similar ports. They offer simple, easy connection to your Ridgid Vac.

There are several users that have built stands, that put the vac over the trash can, and put the whole shebang on wheels. Makes for a VERY portable, and reasonably space efficient dust extraction system.

As the others have mentioned, be VERY careful to not block off the airflow. A shop vac can generate enough suction to suck a trash can flat VERY quickly if you let it...