[g.l.amour]

@bigben,

i used the cheapest of the cheapest plexi knockoff; scratches most easily. also i found that working plexi, especially drilling is more of a bitch than drilling copper. when the drill brakes through the surface it is most difficult to make the drill not bite. this is why some holes have cracks.
when i was almost finished a couple of days ago; i did a 6.5mm hole, one pass through all the layers of plexi, with the copper already attached. when the drill bit through the surface the whole +/-400gram started spinning with the drill. the whole drill started going awol on me. have some cuts in my hand to testify to that. result, some blood, and the whole top was killed.
maybe real plexi or lexan wouldn't be so much of a problem

@puzzdre,

tapping plexi is a no-brainer; drilling however...
i used the cement type plastic glue for the barbs. this is some funky stuff, melts the plastic a little. thats why i'm not all that worried about the cracks.
actually the copper mirrored holes are 4mm dia, the jets are 2mm (per recomendation of volenti). the velocity of the water exiting is quite amazing.

imagine 9jets; 2mm dia -> 1mm radius => surface= 9 x 1² x 3.1415 = 28.27mm²

imagine 1 barb; 10mm dia -> 5mm radius => surface=5² x 3.1415 = 78.54mm²

so the water is being pushed through 1/3 of the normal barb section.

in the copper the holes are 4mm dia and 4.2mm center to center (this is not enough, drill press is not precise enough, 4.5 would've been better). so in the plexi c to c dist is the same.

first block= reference (the one we made together)
second block= -1°C
third block(this one)= -4°C (succes i'd say)
from 40°C load to 36°C @ 5V

one 6 to 8mm plexi layer should do for the barbs.
2 2mm plexi sheets for eventual jet design.

so i repeat myself, tapping is a cakewalk, hold your heart drilling though.

@#rotor
this is why i try to do my best to further spread the gospel. credit from further refining goes out to Volenti and Bigben2k though, they extrapolated Cathar's work to your method.

cheerz