i finally found cheap copper on ebay, $1.50 for 1/4" x 2" x 3", so i'll get 20 of those and try to make 10 WBs. this should leave enough room for some experimantation with the design. here are the 4 main inlet/outlet configurations that i thought of, all of them have a square grid on the inside:
there is however the question of how to mount the barbs. here are the two different schemes that i have in mind:
in 1, the barb is threaded into the top piece of copper. 1a and 1b are 2 diff approaches to that, but it doesnt seem like there would be a diff in performance.
in 2, the barb is soldered on the top piece. the holes that fall under the barb are drilled all the way through. this is much easier to make since i dont have to thread a large barb into copper. i was also thinking that it'll create jets on the inlet.
the barb in 1 is a 1/2" threaded brass fitting. the barb in 2 is also brass and looks like this:
