Wednesday, December 12, 2007

Cigar Box Guitar questions

I had a couple of questions asked about how to make a pick-up and anchoring strings. I thought it a good idea to post my answer on here too.

Q. - "I'm totally fascinated by the cigar box guitar and am trying to put one together right now. I think the first problem was how to get the strings/tail done, and I'm opting to just make very small holes and let the ball at the end hold things. The other problem is amplifying, a piezo has me stumped. I know Radio Shack has them and I've been told they simply wire over to an input jack ... but I was wondering if you have any suggestions as to how I can easily get the thing wired for amplification."

A. - The neck passes straight through the box and out the back about 5cm to provide anchorage for the ball end of the strings. I drill three holes about 1cm apart. I find that when strung, the strings start to cut into the wood so I make a small metal plate out of brass or alloy which I screw onto the tail just in front of the holes so that it takes the pressure of the strings off the wood and stops it cutting through. It helps keep the thing in tune as it stops you losing tension from them cutting into the wood.

Pickup - easy. It's a ceramic piezo transducer disc. Some people buy a piezo buzzer which has one in and they rip it apart. Hard work when you can just buy the disc anyway. It looks like a thin a brass disc with a white coating in the middle (like a fried egg). There are two wires soldered to it, one to the brass outer and one to the coating. Carfeully unsolder them and discard the wires. You need some screened twin cable and a 1/4 inch jack socket. On one end of the cable solder one wire to the inner of the jack and the other wire and the screen wire together to the outer. At the pickup end trim the outer covering back about 2 cm and cut off the screen. Very very carefully solder one wire to the brass and one to the coating where the old wires were. Be carfeul because the coating is fragile. If it breaks off when soldering just try soldering another small blob on another area, it usually works OK. Before fixing to the guitar, plug it into an amp and just tap the disc, if it clicks it's OK, if it's dead then you got it wrong. When OK I fix the socket into the body then glue the disc (brass side) with Araldite to the inside of the box just under where the bridge/saddle is going to be. I also add a blob of hot glue to stick the cable to the lid just to stop it flapping about and ripping your wires off. I don't bother with vol. or tone controls, just use those on the amp. Job done.

2 comments:

clough_mark said...

Anchoring strings:I use pop-rivet heads inserted into the tail. I got the idea from looking at Ted Crocker's brilliant phots from the Cigar Box Museum, go to
http://www.flickr.com/photos/tedcrocker/sets/72157600365357368/
Pop-rivets come in a variety of sizes, so you have some choice. The centre stem knocks out with a tap from a hammer, leaving you with what is basically a metal insert. Just enlarge the string hole to take the rivet head and put it in the hole. I do a 'belt and braces' thing and put rivet heads both sides of the tail.

David said...

Excellent Mark, thanks for that.