Another big thanks to Botnerd for certifying me as a
Journeyman. I appreciate it.
Update on the ROV: I fabricated the plexiglass motor mount,
got the motors fitted, wired up the tether and the control
panel, and would've finished except it was late (10pm) I had
to get up early for work (6am) and I had no #8 screws to
mount the terminal strip for power distribution (RATS!)
The frame fabrication went great. Seriously low-tech, but
here's the deal: I drew the ROV up in Rhino3D (very nice 3D
modeling and CAD package), converted the frame to a flat 2D
shape, and printed it 1:1. The printout was stuck to a
sheet of plexiglass using Super77 adhesive. The trick is to
spray the paper with a thin coat and let it sit long enough
to get tacky. The idea is to wind up with the consistancy
of a Post-It. Once stuck on the plexi it was time to cut.
Holes came first. I used normal twist drills. With light
pressure at the bottom of the hole you can avoid most
chip-out problems, but overheating was an issue. At one
point I made some spade drills for drilling plexi, but
didn't have one in this size. All the holes were drilled to
take a #8-32 tap. I didn't wind up tapping any, but that
way if I want secure threaded anchor points for ballast,
I've got them.
The shape itself was cut out on a scroll saw. I used too
aggressive a blade, so I got some chipping. A finer
skip-tooth blade with reversed teeth on the bottom would've
been better. I even have them, so I'm kicking myself. But
not hard. It's a prototype.
The 3D forming was done using a heat gun and a wooden form.
My "form" consisted of a bunch of 2x4 and 2x2 lumber and
some quickclamps. Cheesy, but I got nice 90-degree bends in
the plexi. Only problem is the wood surface isn't smooth
and now I have wood grain patterns on my plexi. Ah well.
The frame itself came out great and the motors zip-tied
right into place. Wiring the umbilical was a snap, and with
all the holes in the plexi there were plenty of places to
anchor the motor mount into the ROV frame.
Only thing left is power. Then it's time to test!