Again I'm sorry I have not blogged in a while. A Christmas vacation, a waterpark excursion with the grandkids, and general sloth slowed me down a little over the holiday period. I have been busy building a section of my parade float though. I haven't been posting that because I felt you wouldn't find it very interesting if you are following my blog for automata knowledge. Anyway I am just completing the mechanism and characters for one section of the float and I think it's time to return to complete the automata project was working on prior to charging off into the float stuff.
Working with polystyrene to cut and shape the penguins has been interesting. I often emerge from my shop coated in static electriclly charged small pieces of foam. Mix in the overspray from some spray adhesive and you have a mixture that is hard to vacuum! I decided I need to purge the shop and myself of polystyrene residue for a while. The vignette I've done is a trio of penguins, ranging in height form 27" to 32" tall that are waddling along the side of the float. They don't actually move forward but tip side to side in the motion of penguins. Along with a little scenery this will occupy one back corner of the float.
The motion is imparted by what I call my "waddle box", a plywood construct that will drop in the float with a motor gearbox, and rocker arms to mount the penguins on. It looks crude but it will serve the purpose of being sturdy enough to survive the rocking weight while only needing to last a few hours for a parade. It wouldn't be good if pieces of penguin where flying off into the assembled spectators! Each of the penguins opens and closes their mouth as if singing "Drivin' Home for Christmas" the theme song for the float.
I made the penguins by generating a 3D image in CAD, and cutting polystyrene disks to laminate pieces together to make an approximate profile. These pieces have a hole up through the centre to allow for passage of control wires to the beak. Once assembled it is onto shaping by cutting and sanding these forms to a smooth finish. (This is where the mess is generated.)
I've attached a couple of photos to look at and I will followup with an operating video when paint is complete. In the "waddle Box" photo you can see the motor and gearbox behind the belt guard and the rockers which have a black PVC pipe that fits up into the bodies of the penguins. The penguins, (Patty, Maxene and LaVerne, ) have one coat of primer paint on them at this point. The little one has a squarish looking head since the beak mechanism was a tight fit and I was reluctant to sand too much off the head. The odd shape will be hidden by a well placed Santa hat when completed.
Here is an early preview of the girls.
1/24/2018 07:08:10 am
I for one would love to see more about your parade float, after all it is an automata on wheels. Did you use some type of hot wire to cut out the foam pieces for your penguins?
1/24/2018 07:53:07 am
Hi William! I didn't use a hot wire for the cutting. My experimenting showed that while hot wire was fast on styrofoam it is a lot slower on polystyrene. Higher density I guess. So instead of going with a hotter wire cutter I found it was fairly easy to cut the disks on my scroll saw. It has a 2" throat so I was able to pass them through. It actually behaves a lot like a hot wire in that there is enough friction heat generated you can sometimes find yourself cutting sideways! One advantage is that when melted polystyrene can get harder and this can make sanding more difficult; with the scroll saw there was no burning. Lots of fine cuttings though but the dust collector could pick them up. Once assembled, I tapered the overlaps of the disks with a small hobby box cutter. The thin blade would bend allowing me to do some shaping. The big utility knives are too stiff for this.
1/24/2018 07:55:30 am
When I'm working on my next one I'll blog a few more photos and discussion.
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Automata is a creative blend of my life interests , engineering, art and woodworking.