Big tools and dust collection

[Tpt life]

1 hour ago, rodger. said:

Not too wild about drilling a 6" hole in the side of my brick house. So I got to thinking...

A 6" hole has an area of 28.26 square inches, and would require a lot of work to drill out (and disturb 4 -6 bricks). However, a rectangular vent that requires the removal of one full brick, has an area of 32.5" (brick is 10x3.25).

The rectangle vent is equivalent to a 6.4" round hole.

Does this make sense? Is there any reason that a circular hole is preferred to a rectangular hole?

 

Surface area creates friction. The best surface area to volume ratio is round. If you go rectangular there are some calculations for picky stuff. You can just try to overshoot by ten percent or so likely. If you find the right system, you can likely find a transition from round to rectangular. 

[rodger.]

5 minutes ago, C Shaffer said:

Surface area creates friction. The best surface area to volume ratio is round. If you go rectangular there are some calculations for picky stuff. You can just try to overshoot by ten percent or so likely. If you find the right system, you can likely find a transition from round to rectangular. 

The exhaust would normally be 5", if I matched it to the intake. So if I go 6", would that be a good cushion?  Due to the rectangle, I also get an additional .4" (which is like 6 percent in addition to the 6" hole).

I will go 6" round duct right up to the wall vent.

[Tpt life]

@rodger. I am just pushing the concept out there. I claim no experience in the calculation. What you propose, I would not hesitate to try. 

[KenMasco]

Her's what I did.  1.5 HP 1200 com delta blower, cartridge filter, SDD, 4" black sewer pipe and Ivac blast gates.  Three runs of pipe, the longest is 20 feet.  Can't see the need for anything more.