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Permalink Reply by Taffy Evans on January 13, 2020 at 11:38am

Hi James, my experience is from full size resonator guitars and cbg style dog bowl reso's, but the principals are the same. I'll to give you some info that will help you with your design. Part of the fun of cbg's is in designing ones own guitar.

1- The top can be flexible but thicker/stiffer than a regular guitar top. Full size reso's usually have the top connected to the back forming a sound chamber. Imagine a tambourine without the rattles.

2. I do not use a sound chamber see my recent post on a resonator guitar build its all shown there, you could adapt what you see there to your build.

3- I put bracing where the top feels/looks weak. In the photo bracing is around the pickup and sound hole cutouts. One cross brace [shaped like the back braces] between the large hole and the pickup hole. The large resonator hole is supported by the sides and tail block. 

4. I do not use neck trough style so the neck block is a bit oversize to take a 6 string neck.

5. You say top and bottom are thin??? In my world under 2mm is thin. 

6- My thinking is, if want your tin lid to work better stiffen the top so the string energy is driving that and not soaked into the timber surrounding it so easily.

7- Although resonator Guitars have a distinctive sound, the main function is to improve volume.

8- The smaller cbg is the size you are going to use. Position the lid/bridge assembly first then plot the neck position. Taff

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Permalink Reply by James Pobog on January 14, 2020 at 10:58am

So does the top of the lid take the load from the bowl, or does the bowl sit on those 2 rails and simply poke out the large hole in the top? I understand how a paint can lid will load the top, but I found a nice tinny ring bowl last night..

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Permalink Reply by Taffy Evans on January 14, 2020 at 12:32pm

Hi James, the two rails you refer to are braces to stiffen the back. The sides are deeper than the bowl so it floats above the back suspended from the top.....

The only support is around the rim of the lid or bowl, otherwise you will dampen the resonator. This top is about 5mm thick in this case.

You could support the top like this if needed, or brace it.

This shows the extra bracing and thin veneer supporting the cutout areas. On a different cbg though.

Keep in mind that the top of any acoustic stringed instrument is the most important part, its where the sound starts from, after being excited by the strings, weather its tin, spun aluminium or timber, that sucker has got to vibrate the best it can.

Taff

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Permalink Reply by James Pobog on January 15, 2020 at 3:17am

Got it. Mostly. First let me say your skill set is far above mine. I really am a hack, flying by the seat of my pants. Thanks for the pix.

So you do (at least partially) add thickness to thin tops or areas, right? Is this pretty much it (for a neck-thru)?

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Permalink Reply by Taffy Evans on January 15, 2020 at 12:02pm

Hi James, With your resonator guitar your idea in the drawing would work [but not for a full acoustic none reso instrument.

I would also suggest that the bridge be in the centre of the lid for best / better results. Then work out neck positioning. If you are supporting the top with a through neck I don't think you will need a post as a support too. Nice drawing by the way.

Taff  

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Permalink Reply by James Pobog on January 15, 2020 at 12:24pm

"With your resonator guitar your idea in the drawing would work [but not for a full acoustic none reso instrument."
All my builds are electric primary, and acoustic only for quiet noodling.

"I would also suggest that the bridge be in the centre of the lid for best / better results. Then work out neck positioning."
Thx. It's small finesse like that that I don't have a clue about.

"If you are supporting the top with a through neck I don't think you will need a post as a support too."
On second look, I agree. This neck will be red oak. I also think the little supports aft of the reso will be instead the neck itself, the neck being dado'd for the reso.

"Nice drawing by the way."
Thx. 15 minutes with my wake-up coffee at 6am in Paint. Mostly filled rectangles.

I'm gonna show you a pic of the dog bowl I have later after i get this thing out of my head...

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