[bigben2k]

3/8" preferably, but will settle for anything right now. Need a 3" wide strip, enough to construct a box.

I'm also leaning towards a smaller diameter; 32" is not handy (bordering on ludicrous), and would have wheels, like fantester's biggest unit. I have no problem/concerns/qualms exceeding the specifications, if testing an 8" by 6" core, on a 24" diameter tunnel.

Got a source for 24" concrete formers? At 24", we could split a 12' length.

Yeah, I'll get the motor first, then try it out. If I want to add motor control, I'll do it later. Lost the blower; better luck on the next one.