Got my 2nd "DIY" box fan home, and as I have had a few questions about the "box" on my exhaust. I figured I would show it here, as I had to change the flow direction. This fan is a little different, as I made it to run cool tubes. Years ago I had both 4" and 6" cool tubes, so I made this fan to fit both types.
Then I can just change the flow direction, as I got it home it's setup to push the air thru the 2x 4" falges. This I will change, as the tubes Im gonna use are 6"
I can simply unscrew the lit, that gives access to the fan.
Then unscrew the end peaces, with the flanges.
Swap them around and remount them
Now the fan is ready to push air thru my 6" cooltubes. (Pulling hot air, thru the fan will shorten it's life)