Building the Brain

Aluminum Brain
Brain Pan Wraparound Panels Wood Form
Brain Pan Wraparound Panels Wood Form
   I elected to build the brain out of aluminum. The triangular upper and lower sections are 1/16" sheet aluminum, and the side panels are a thinner aluminum which started out as a kick panel for a door. The outsides were cut with a scroll saw. To cut the shapes, I first scanned the patterns from Dave Painter's plans, then printed them on full size laser label media and stuck them to the aluminum sheet. I used a drill press to cut 1/16" holes inside the shapes, then used a Dremel tool with a small ball cutter to connect the holes, and finished off the shapes with a set of needle files. The eye holes were enlarged slightly to accomodate Mark Thompson's eye lenses.

Bottom Plate Top Plate Ledge Front Panel
Bottom Plate Top Plate Ledge Front Panel
   To keep the wraparound panel properly secured and shaped during assembly, I cut a duplicate of the bottom plate shape out of 3/4" pine and used plastic push pins through the cutout holes to fasten the wraparound to the wood form. I also used the wood form to bend the wraparound panel. The 5 rectangular objects on top of the wood form are some scrap 1/4" acrylic, to raise the bottom plate high enough so the adhesive would not stick to the wood. I used J-B Weld to glue the bottom plate to the wraparound panel. The join was not perfect, but I was able to pack in enough J-B to fill the gaps. I used a long aluminum bar clamp to hold the bottom together. Note - before you apply the J-B Weld, be sure to roughen the edges of the join with coarse sandpaper or a file, or else it won't stick well.

Eye Pieces Top Plate
Eye Pieces Top Plate
   The open ledge to support the top plate was attached in the same way as the bottom plate, with the wraparound pinned to the wooden form. Then, the wooden form was removed and the front panel attached with more J-B Weld. The eyepieces and two smaller filler pieces were then attached, more J-B Weld was slapped on to fill the cracks and a couple of scratches, and I did some preliminary sanding. The top plate fits snugly into the top of the brain.

Brain Cup Parts Prelininary Cup Tubing Cutter
Brain Cup Parts Preliminary Cup Tubing Cutter
   I found a tapered aluminum cup that appears to be some sort of weird looking salt shaker, but has almost the perfect dimensions to be used for the brain cup. I cut a 4-1/2" aluminum ring to form the bottom part of the cup, and a 3-3/16" disc (slightly larger than the 3" disc called for on the plans) for the top. Also in the picture is the 12V, 7RPM Hankscraft motor I got from Mike Joyce, to turn the crown and move the light rods. The second picture shows the cup after I flattened out the top of the cup and attached the top plate and bottom ring with J-B Weld. I filled in the seams with more J-B Weld and did some preliminary sanding. And finally, why do anything simple when you can do it the hard way? I wanted to cut several sections of nested brass tubing, hence the odd looking Dremel rig.

Brass Tubes Light Rods Drill Press Setup
Brass Tubes Light Rods Drill Press Setup
   I decided to make my light rods out of brass tubes. At first, I experimented with 1/2" aluminum rod, but after failing to drill out a centered hole and discovering I had nothing which would turn down the ends, I gave it up as a bad deal. I picked up a set of 12" nesting brass tubes from K&S at the local hobby shop, in sizes of 7/16", 13/32", 3/8", 11/32", 5/16" and 9/32", and 2 sections of 1/4" tube. According to Craig Reinbrecht's measurements, I cut the 7/16" tube in 11/16" lengths, nested the 13/32" and 3/8" tubes and cut them in 1/8" lengths, and nested the 11/32", 5/16" and 9/32" tubes and cut them in 3/8" lengths. Finally, the 1/4" tubes were cut in 3-15/16" lengths. The nested tubes were then soldered with a mini butane torch and silver-bearing paste ("Solder Weld" from Radio Shack). The net result looks a lot like Craig's diagram.    In order to attach the pushrods to the light rods, I drilled a 1/8" oblong hole through the top of the light rod near the end for the 1/8" brass pushrod. Then I used a tiny 1/32" bit to drill a hole through the side of the tube and the bottom of the pushrod, for a piece of piano wire as a hinge. The right hand picture shows my drill press setup for the 1/32" hole. Buy 2 of these drill bits - you'll break one. :-)

Cup and Rods Inside Cup Painted Brain
Cup and Light Rods Inside the Cup Painted Brain
   The sockets for the light rods are from Radio Shack, with a Dremel tool and cutting wheel used to remove the bracket. A length of 22 gauge stranded hookup wire was soldered to the center post of the socket, then the socket was soldered to the end of the light rod with solder paste and the mini torch. The wire is led out through a small hole in the light rod right after it enters the cup with a short length of spaghetti tube to keep it away from the edges, and a ground wire is soldered to the outside of the tube right next to it. I painted the light rods and brain cup with self etching primer and Duplicolor Cast Coat Engine Enamel CT302, then attached the pushrods to the light rods with a piece of 1/32" piano wire, bent over to keep it in place. The rest of the brain was also painted with Cast Coat, along with 3 short (3/8") pieces of 7/16" brass tube to cover the topside light sockets. I didn't like the looks of the bare sockets sticking up. The brain cup is attached to the rest of the brain with four 6-32 machine screws threaded into holes tapped in the top of the cup.

Neck Plate Neck Pipe Attached Inside the Bubble
   The neck support is a length of 1-1/2 (ID) PVC conduit, with the flared end at the top to hold the Hankscraft motor. I glued a couple of flat PVC round pieces to the top of the pipe to provide a flange to screw to the ring on the underside of the bubble plate (1/4" curved version from Planet Plastics). Four 6/32 screws attach the lower ring to the top of the neck pipe, through the bubble plate. In between the ring and bubble plate, I inserted a 1/8" foam ring (Trackbed, at your local hobby shop) as a spacer. Another foam ring sits underneath the brain cup on the upper side. Four more 6/32x3/4" screws attach the brain cup to the lower ring, through holes tapped in the brain cup. Finally, I drilled four holes on the perimeter of the bubble plate, 3/16" in from the edge, and countersunk them. I carefully tapped holes in the bubble itself for 6/32x1/2" nylon screws, and screwed the bubble plate to the bubble. The white nylon screws aren't too obtrusive, although I would have preferred to use clear acrylic screws (couldn't find any around here).

Crown Parts Riveted Crown
View from the Top Crown Parts Riveted Crown
   The eye lenses are from Mark Thompson, and are just press fit in place, for now. The vanes for the crown were cut from .032" aluminum with a scrollsaw, then sanded down to size with the disc sander. The 4" circular plate was cut from 1/16" aluminum with a circle cutter on the drill press. The holes were drilled, then I did a first pass with the polisher on the circular plate. The vanes were then bent to a 45 degree angle in a vise, and pop-riveted to the plate. I'll polish the vanes and attach a collar to fasten the crown to a 1/4" shaft.

Last updated on Monday, July 28, 2014