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Permalink Reply by Jerry Jordan on May 1, 2017 at 8:52am

Hello,.,it depends on what your building and what materials you have., 1/4" to 3/8" is fine.,some are made with glue and sawdust, some with solid wood, some with laminates, and some with paper pulp.,.I have used very thick solid Pine and put the piezo in the saddle and it worked fine.,I used a very thick lidded Sawdust n glue box and a piezo glued to the lid sounded fine.,There are 2 camps , the heavy builds and the light builds. For loud acoustic builds I go light., but a thin lid braced over a heavy box sounds good.,.,on a light build the back and top become the resonator.,.,the bottom line is there are no rules .,.,experiment.,.,you'll like it.,,.

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Permalink Reply by Jimmy Parks on May 1, 2017 at 8:58am

Thanks Jerry. These are high quality solid wood boxes. I will initially be building acoustical, as I have not ventured into the electrics yet ( fairly new builder). I will let you know how they come out.

Jimmy

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Permalink Reply by Timothy Hunter on May 2, 2017 at 11:27pm

if they dont turn out loud enough you can always add a pickup later...go for it.

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Permalink Reply by Moritz Voegeli on May 3, 2017 at 8:37am

A good wooden box is just one factor to get a well sounding acoustic cbg, others are: the neck should pass free through the box, without touching the soundboard nor the botton of the box; nut and bridge from bone are far superiour to any other material. 1/4 inch is not really thick. As to cigar boxes you will get rather problems with small ones with very thin and delicate bottoms like the beatiful and well sounding Avo boxes which you have to use lid up.

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Permalink Reply by Paul Craig on May 3, 2017 at 8:46am

Most acoustic guitar tops are about 3/16ths" or 1/8ths" thick. The thinner the top, the more it moves when it vibrates creating stronger sound waves to echo in the hollow chamber.

Thicker wood will not move as much and have weaker sound waves.

I made an acoustic CBG out of Cedar awhile back. The pieces used were 5/8ths" thick. I used a router to remove 1/2" of the material in the center of my top and back pieces all the way to the edges. This allowed the center to move more, made the chamber taller and kept the side joints strong.

This is easy to do with a good router. You can even leave a thick area for bracing. 

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Permalink Reply by Michael Fred Johnson on May 6, 2017 at 4:34am

Just spent the morning modifying a three year old build with the thinned out lid you describe.

I had left the thicker area for bracing but the bridge area still sank over time,thin out as much of the front as possible and brace it with struts

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Permalink Reply by Paul Craig on May 7, 2017 at 6:21am

That's the problem with thin tops on acoustic guitars you can't get away with. It's best to have a long bridge to place the stress across a wide area like you see on big acoustic guitars or you can use a "tone block" like Violins or big Jazz Box guitars.

A "Tone Block" is just a 1" square piece of wood under the bridge going from top to back to keep the sag at bay. It hinders the top's vibration wave some, but adds some sustain.

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Permalink Reply by JL on May 7, 2017 at 9:22am

In a violin its called a sound post and can help with volume getting the back panel to vibrate with the front panel, as well, its placed right close to the trebble side, and a longitudinal brace runs under the other side called a bass bar to add strength.

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Permalink Reply by JL on May 7, 2017 at 9:28am

the beauty of our mantra "there are no rules" is the implication of testing something out for yourself, not accepting conventional wisdom  as gospel.  Copernicus, Galileo, and Newton challenged conventional wisdom that heavier objects fall faster, now we have rockets that reach orbit.

you have a wonderful opportunity to test out the thickness of the lid, take it apart and thin it some more, try again, see what happens.

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Permalink Reply by Paul Craig on May 9, 2017 at 8:31pm

True, but sometimes the old Conventional Wisdom works very well. If it works, don't change it. If it doesn't work, then indeed try something else.

I have a 1960's Japanese made clone of a Gibson ES330 guitar. It's body is hollow  and uses some type of plywood without bracing except a tone block under the bridge. That block has kept the top from sagging under the pressure of 6 strings all these years.

Using construction methods of the past doesn't interfere with "No Rules" mantra, it's just a way of fixing a problem. No reason why regular guitar construction methods can't be used in making /constucting CBG's.

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