Doming

[AidanHarris]

Hey all,

I have a feeling that I'm going to be asking a l of questions in the coming weeks and months haha.

So I've been reading the Somogyi books, I guess this guy knows a bit about guitars :-p he talks about domed backs and glueing bracing on using a curved work plate or solera. How many of you guys dome your backs? Is it necisary for me to do or is it more of an aesthetic addition? Would you consider it an addition that adds value to the instrument?

From what I gather he does it to reduce the effects of wood shrinkage being noticed (correct me if I'm wrong)

Just wondering about it and if I will have to sort out one of these domed work surfaces.

Cheers guys
Aidan

[jeffhigh]

Arching the back across the width has been pretty well universal for the last century or so. Various longitudinal tapers or curvatures have been used but the use of domed dishes is more recent.

I would not want to build a back without doming.

[kiwigeo]

Hi Aidan,

The backs of my classicals and steel strings all have a 15' radius dialed in. I use an appropriately radiused dish to sand the sides and then to gule in back bracing to achieve this. When Im building classicals using the Spanish Method I use a workboard which has a hollowed out area around and south of the bridge.

The reasons I've come across for doming the back:

1. It increases strength of same.
2. Allows for shrinkage and expansion of the back wood due to RH changes.
3. It improves projection of sound....some argue this is very noticeable on Ovations with their bowl backs.
4. It looks good.

[jeffhigh]

Think of radius dishes as part of a system too with the addition of sandpaper and a go bar system
You can sand the braces to shape on them
You can sand the edges of the rims (sides) to a dome to perfectly match the back and soundboard
You can glue on braces to soundboard and back quickly without all sorts of complicated clamping arrangements
You can glue on soundboard and back with go bars and without spool clamps.

[gpj1136]

I build with a domed back, but use no radius dish just a few shims in the right places. You do not need a perfect dome shape. Older guitars do not have one. It is one of the newer developments. After you carve a radius into the braces, even if you force them down flat while gluing, when you remove the back or top from the go bar deck. It will retain the radius.

[Taffy Evans]

I use a radius in my backs as the guy's above and for the same reasons, a flat back can look sunken, I tried it once and did not like the look of it.

[AidanHarris]

Cheers guys,

Thanks for the help and clarification! I'll see what I can sort out now

Aidan