Tuesday, March 11, 2014

Another Special Tool

Bending the sides for an acoustic guitar is crucial to the shape and final result, a matched pair of ribs that fit the overall design of the instrument.   I suppose there are any number of ways to accomplish this.  And, commercial benders are available, but for a huge price.  So, I decided to create my own.  It didn't seem like such a complicated affair -- a method to apply heat to the wood at specified points, and a stable platform on which to apply pressure to shape the wood -- so, take a look at the simple device I chose to assemble.

No it's not a spud gun.  It's a TotalRojo acoustic guitar rib bender.

For less than $40 in parts and a couple hours labor, I created a simple bender.  Because of the hand pressure needed to be applied to the straight wood guitar sides during the bending process, the unit has to be secure and comfortable to use, so I constructed it with a wood base that would fit into the jaws of the small bench vice.  It can sit horizontally (see photo), or can stand on the end (see the lip extending beyond the back), whichever is the best position needed.  

I chose two-inch copper tube for the heater (geez that stuff is pricey - $19 a foot).  Found a 600-watt heating element on Ebay from China for three-and-a-half bucks.  A light dimmer switch for $4+, and three feet of heavy-duty wire and plug for another five bucks.  A two-inch metal washer and conduit clamps from my junk drawer.  A cigar box laying around for a future as an amplifier did the trick for a 'control' enclosure. A roll of aluminum foil pilfered from the kitchen.  And, a copper cap to hold things together.

Acquiring the copper tube and cap was a hoot and worth telling about.  After searching all over town for 2-inch copper tube, I finally landed at Powell Supply.  I've driven by the place for twenty years, but never had the need to stop in.  It was like going into a time warp, straight into the fifties (perhaps earlier).  An office on the left, entry way cluttered with stuff straight ahead, and parts department on the right.  It didn't smell like a hardware or electrical supply store, whatever they really smell like.  It smelled of delicious food!  The combination of vegetables, meat, garlic, and gawd-only-knows what else, but it smelled good, and I was hungry.  Why the food?  To feed customers, what else.  You sure as hell never get this treatment at Lowes or The Home Depot.

The guy at the parts counter fixed me up with the tube and cap.  I offered to pay him, but he said, "You gotta go across the hall to the window, and my mom will take your money."  Ok, off I go with invoice in hand to see Mom.  The window is like what we used to see in old theater ticket booths or at old bank teller stations. Mom is an older gray-haired lady (and very nice I might add), who was reading something when I approached her window.  She must not have seen me, but another older family member let her know I was standing there looking bewildered with money in my hand.  She looked at the invoice and proclaimed, "That copper is sure pricey, isn't it son."  Son, hell I'm 73 years old, so how old must she be?  I asked, "Why is that?" She replied, "Because, folks are stealing it right and left."  It doesn't make sense to me that the price of something should be governed by theft, but I wasn't about to get into a discussion about that.  I just picked up my stuff, stuck the change in my pocket, smiled, looked around for nostalgia sake, and left the building.  I look forward to the next visit at Powell Supply.

Enough of that.  Here's the detail of the construction process, which is simple.

I placed the metal washer inside the tube at one end and used a hammer to crimp the edge to hold the washer in place.  Then, I stuffed the tube full of aluminum foil (tamping it down tightly with a wood dowel and hammer), which is there to conduct heat. Drilled a hole into the center of the foil to accommodate the heating element. Ran the element wires through a small hole drilled in the copper cap and into the cigar box through another small hole.  Packed the cap with foil and slid it onto the tube, where it was secured with screws in holes drilled in the cap and tub.  Mounted the dimmer to the cigar box lid. threaded the plug wire through a small hole in the box and attached the plug.  Attached all the wires in the box to the dimmer.  Ran a ground wire from the dimmer to the copper tube, where it was secured with one of the screws, so I wouldn't electrocute myself, if I ever accidentally touched the dimmer mechanism at the same time I touched the tube. Secured the tube on the base with the clamps.  Plugged it in, adjusted the dimmer control, and voila, heat in the tube.

That's it.  Pretty simple, and I like simple.

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