after all the cad work and tons of calling and researching about 10,000 different investment casters, die casters, milling shops, 3d printers and everything under the sun, i've come to the conclusion that the amount of money i'd need to spend to get the tank done in its current design in metal just isnt worth it. i've started to do some research on resin casting with a more durable and protective material. ill see how that goes and fill you in as i find out more. if i do a metal version, i'll have to rethink the design completely. this was a tough thing to come to grips with. bummer.