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im sure this topic has been discussed so a link to the thread would be welcomed. ive noticed some great looking 3 piece backs on guitars and was wondering how many pieces could be joined to create a plate before it would start to lose structural strength or the glue would dampen the vibration. i would think that the soundboard would have a more dramatic effect than backs or sides. has anybody had a problem or noticed a lack of tone from a 4 piece or double bookmatched top or back?

I've added wings on may occasions to stretch a narrow top into the "hips" of the guitar. so far I've sed the same wood and tried to hide the joint, but I know there are others about who'd accentuate it.

modern glues shouldn't damage the tone a lot if they're clean joints.

I've heard it said that this will be more & more common as the supply of really big trees for tops runs out

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Generally everything you do will have an affect on your tone,but that being said,think this is very far down on the list of things to worry about as long as you use good workmanship.Think this is mainly about looks and design.

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It is a very interesting question.

Structural strength isn't a problem if the glue joints are done properly. The glue lines will be stronger than the surrounding wood. (See the recent post on using a Jointer for all sorts of discussion on proper glue joint prep)

There is a fellow around here somewhere who made up several "Scantling" guitar backs... I think it was something like 10+ strips of BRW jointed together. His claim was that it sounded good, but not as good as a "Standard" BRW 2-pc back.

There is another fellow on here somewhere who did a 7-piece Cedar topped steel string. He didn't bookmatch the pieces -- just glued them up sequentially wide grain against narrow grain. It looks quite striking.

I personally have 13-piece and 15-piece "Tops" I made up from Spruce lumber strips during Jointing practice sessions. I really want to try one out on a guitar to see how it will sound.... My building rate is quite slow, so it could take a while before I get around to it.

Thanks

John

Someone posted a pic of a 4 piece adi top a while back. You can barely see it even what looking for it. You can use better wood at a less expensive price. Like others have said, the affect on the tone is probably negligible. It would actually benefit tone if you're using better wood that otherwise would be too narrow for a top.

thanks for the 411. using better quality or a tighter grained wood was the intended reason behind the question. and i have a cedar top that ive made shortly after building my shooting board. was resawed from a 1x3. it made for good practice and a real confidence builder.

I seem to recall that Torres wasn't too picky about how many pieces of wood it took or how they matched cosmetically, he just used the best he could get his hands on. If someone can verify my memory, then that's a pretty solid nod to 'it's OK'.

I have also heard, from Those Who Would Know, that two-piece tops aren't going to be the standard anymore within a number of years you can probably count without running out of appendages or just a few more than that. We need big trees to get two-piece tops out, and big trees make a lot more 2x4's than small ones...

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

That's right Bob, Torres used the best wood available to him (remember he couldn't just call Allied or LMI) he was much more concerned with the qualities the wood had rather than its cosmetics or size.

Romanillos shows that for backs he made:

30 - 2 piece, 37 - 3 piece, 14 - 4 piece, 2 - 5 piece, 1 - 6 piece and 4 unknown number.

and for tops, 60 - 2 piece, 13 - 3 piece, 3 - 4 piece, and 12 unknown number.

Torres guitars are still the standard that classicals are judged by, so if it was good enough for him........

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

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Anyway, I have done mostly 3 and 4 part backs since my shop ceiling is too short to allow me to get the riser for my band saw yet. Aside from the 'joys' of joining the plates I have had no issues with it effecting the sound quality of the finished instrument. A little extra bracing on the back helps with paranoia about the joints holding up.

-Matt