Duct collection question(s)

Stick486 said:

use the 26GA...
tape the seams...
use rubber cement as gasket material... thin layer on one part and assemble after dry...
use saddles instead of fittings... hose clamp them on..
use these style of reducers..
see if a wholesaler will give you a break...
.

Click to expand...

Sounds like sound advice! Thanx for the .pdf!

I've gotten others (on another forum) who have stated they didn't go the route you mentioned, rather they reduced to 6" PVC immediately out of the DC and reduced to 4" lines fairly quickly. Then there are yet others who have recommended a mixture of the two (metal vs PVC, reduction "out of the DC"). My thinking is that I wouldn't want to reduce to 6" lines until after the first branch, and reduce for 4" lines for the down-drops.

Maybe I'm being too picky about "leaky" systems and the aesthetic of the spiral pipe vs. snap-steel vs pvc (thin wall or schedule 40).

My set up will basically be:

1) 15-18' run across the "back wall" of the shop which will service:
A) a small line to my bench (against a wall)
B) router table (Triton TRB001 2" dust collection hose)
C) radial arm saw,
D) 18" band saw.
-[The "small line" will be a sweep-type opening for brushing stuff into
and a 2" line for small cleanup]
-B and C will likely be a "Y" where both are either open or closed for air movement purposes.

2) a 10-15' run to the center of the shop which will service the Robland X31.

3) Somewhere in there I need to put in a floor vent for cleanup.

So I would think the following would be the starting point:

.....................Robland, 4" drop
......................|
. ....................6"
|----|..............|
|DC |---7"----Y-----6"------T---------T---------X
|----|..............................................A

The periods are to be ignored -- they are there for spacing purposes only.

Where the "T"s are each 4" 45 degree angles into flex hose. The flex hose runs will be about 6-8' each, coming from roughly rafter-height where the 6" line is. The "A" is a 4" Y 'splitter' that will either be both-open or both-closed (via a gate) to feed the Radial Arm saw and router table. I have these both open due to the restricted air flow from the router table and its expected decrease in efficiency. The "X" at the end of the run will be a "gradual 90" to 4" line to feed the bench sweep, and I'll put a 2" "Y" near the "bottom" of the run for the vacuum hose line.

Theoretically I could switch to PVC at the 6" runs. Savings would be measurable, but I'm blessed with a good budget. Is there an advantage (other than price) by switching to PVC?

[BEGIN EDIT]:

I just read the Bill Pentz site article on Ducting (Thanx, Stick!) https://www.billpentz.com/Woodworking/Cyclone/ducting.cfm and it covers ALL of this stuff.

Stick, your initial advice is SPOT ON with that article in mind. I think my design idea (made before reading that article), with the thought of using the 26g spiral ducting, is correct.

[END EDIT]

I'm sure I'll come up with more stuff to dither about...

-M

I went w/ an 8'' trunk line on the smaller unit w/ one long sweep (pricey) set at ankle height to service 2 walls...
didn't need to lift to the ceiling, for that I went w/ a lot less LF and fittings for a major increase in efficiency, simplicity, and I saved a lot of money...
reduced at the machine w/ a saddle...
if the machine needed 2 pickups I went w/ 2 separate pickups instead of using Wye's...
keep in mind, every time you reduce, add a fitting or length you reduce air flow and efficiency...
you can put a saddle exactly where you need it and relocate them as required...
if you have the talent, you can make your own saddles... buy one and use it as a template...

commercial snaplok is a available in 10' lengths and spiral in 20' lengths...

Economy Aluminum Foil Tape w/o liner or heat rated is all you need as long as it's not imported or the cloth duct tape... use the plain tape w/o printing on it... printed on tape is spec'd tape and overkill for your application...
if you want to ''weld'' the tape on, clean the metal w/ DNA 1st to remove the salts and oxidation..... Distilled white vinegar works too but you need to thoroughly rinse...

''paint'' the inside of the saddle's flange w/ rubber cement to make a gasket.. let it dry before installation...
if you make your own saddles, fibered joint mastic w/ mesh tape is the best way to seal the take offs..
A better grade of Siliconized Caulk (I'm not a fan of DAP) or Vulkem 116 works well too... Vulkem is 1st choice but it's a product you need to learn and has a long cure time but is pretty much bullet proof. tools beautifully w/ thinner wetted finger and a little goes a long ways...
Great for gaskets too but if you put parts together while it's wet you can about give up the idea that you'll be taking things back apart w/o destroying something...
clean it up while its wet w/ turps/thinner or all bets are off...
if it dries on your hands, it's there for the duration... (week or two).. scrubbing w/ a coarse rag and baby oil will help get it off of your skin sooner.. other wise you'll loose hide if you try and force it by other means...

DO NOT use pure silicone caulk... it will ''eat'' the metal...
ALWAYS clean before you tape, mastic, caulk or rubber cement...