Sunday, July 4, 2010

The Bends, and the Bender






So here is Big Bertha, the side bender.



I abandoned the idea of using the hot plate controller when 1) I realized the little nichrome coil is a "booster" that compensates for the heat loss of the huge aluminum bracket that thermally connects the heating element to the bimetallic strip contact. So it would not have really worked. Since the charcoal-starter was 500 Watts, a simple 600 watt dimmer works just fine and is more compact. And a mere 6 dollars

Bending the heater was tricky and in fact, I overbent it producing a "crack" in the outer copper, which is filled with a long nichrome coil and sand.


The exposed coil was not shorted to the copper shield and still heats evenly so I stuffed it down the 2" pipe, supporting the terminal ends with a wad of aluminum foil to keep the leads centered and not shorting each other. This was wired to the dimmer. The whole things sits on rescue plywood.



I plugged it in and...... no go. So out with the multimeter. And it was fine, but I had the "on" and "off "confused. The exposed nichrome makes a handy initial heads up for whether the coil is heating. I'll borrow a IR temperature gauge from work on Tuesday and calibrate.

Meanwhile, I had to try it. I trotted off to the local Woodcraft and bought a couple of pieces of 1/16" walnut. On and "sizzling", I tried to start bending. This is an incredibly tactile process. Initially, nothing was happening even with the wood drying out and sizzling. At some currently unknown temperature, the springy, stiff board yielded like soft metal, wrapping itself around the 2" diameter pipe almost effortlessly. Its a magical feeling to hold this sinuous piece of wood that was just moments before a straight board.



The wood was 1/16" which is a little thin for guitar side (0.090" to 0.085"). I am planning to build a thickness sander next from plans I got off the web (that will take a while), so I am looking around locally for a place to get some wood (mail order) and thickness it elsewhere.

Off to Baltimore for fireworks tonight and Community Forklift tomorrow (a Federal holiday) to look for rescue wood, steel rods and pulleys for the sander. TTFN and a Happy 4th.