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Step 1: Parts Selection and Layout
I usually begin each of my pieces by arranging various found parts on the floor like a jigsaw puzzle until I start to see a shape that I like. In this case I had already collected a number of objects that I hoped would add up to a Praying Mantis. The main basic elements were: a pair of gas pumps to be made into pinchers, a set of four curtain rod brackets to be used as leg elements, a propane tank for the body, a hanging lamp for the abdomen, and the arm from a scroll saw to form the upper body.
Step 2: Pinchers
Step 3: Fixtures and Mounts
As eager as I was to test the front arms, I had to finalize how some of the main body parts would fit together first in order to get everything to the point were testing it would be possible. One major hurdle was how to attach the scroll saw arm to the curved surface of the propane tank. This connection also had to be removable to make servicing and transport of the piece possible.
Step 4: Wings
Step 5: Head
In the research phase of this project I looked at a lot of photos of Praying Mantis's. They have very small heads relative to their bodies, and nearly all of this small area is taken up by their eyes. I wanted my sculpture to maintain a likeness to the actual creature but still convey a lot of character. This would mean the Sci-Fi inspired trick of evil glowing red eyes. I selected some brass wide angle peep holes from apartment doors. With a single small LED placed behind the lens I got the effect I wanted. They were then mounted via black plastic into the bag attachment portion of old Kirby vacuum cleaners.
Step 6: Final Assembly
The title of this step is a little misleading as it did not signify the completion of the project. In order to move on to the actual final step, the electrical work, I had to be sure I was done with all the welding and cutting. Once motors, switches and wires are involved it is no longer safe to add the heat that welding requires. So, at this point I had to shift gears and settle on how to build and attach the legs, and mount the motor that would drive the front pinchers.
Step 7: Electrical System
The only truly off-the-shelf part that went into this project was a little timing relay. In years of building kinetic sculpture I have learned that people cannot be expected to understand that they have to turn something off when they are done with it. To preserve the life expectancy of these pieces I came up with a system (with a great deal of help from my friend CTP) where the viewer presses a button to activate the motors. The piece runs for a few moments and then turns itself off. While this system is relatively very simple, it adds to the complexity of the final wiring. Since I am an artist and have no training in electrical engineering I have had to come up with a notebook full of "maps" of how to put different systems together. I have included a scan of the basic design which went into this piece as well as the relevant parts numbers for different suppliers of this particular relay.
Step 8: Its Alive!
At long last the beast is up and running! In general I am very pleased with the way that everything worked out. I feel like the sculpture is a good balance of menacing and delicate, two things I try to keep in nearly equal measure in my work. I hope that this instructable has been enjoyable to some of you. If you did like this project please visit my website: www.nemogould.com to see my full portfolio.
P.S. thanks to Siblia Savage for the classy final photos.