Three piece back

[gtrboy77]

I was wondering, do three piece (or more) guitar backs require reinforcement strips on the inside at each one of the seams? I’m debating on doing a three piece back, because I’m building a jumbo and none of my wood seems to be quite wide enough. I’ve never had a chance to see a multi-piece backed guitar in person and take a look at the inside.

[Glen H]

If you plan to have an inlaid back strip between each piece then typically you would use a reinforcement strip inside. If none then some will omit the reinforcement. I normally don’t inlay a strip on my back but still do the reinforcement strip on the inside. If it were my three piece back I’d take the extra couple of minutes and add the reinforcement.

[charles Tauber]

I'm not fond of the look of three piece backs, so I've never made one. I reinforce the centre seam on two piece backs and on four piece backs, but don't reinforce the other seams of the additional pieces.

[John Arnold]

If the wood lacks an inch or less being wide enough, I would add wings on the lower bout. Ideally, these wings can be made from the same piece, cut from the waste area in the upper bout. That way, the color and grain match, so that the wings will not be noticeable.

[redir]

I have made four piece backs before and use spruce cutoffs for the center seam and for what ever back I am using I use cutoffs from that to reinforce the two outer joint lines. Seems to me like it's a good idea.

This is one of my guitars, though I didn't build it, that has a 3 piece back with spruce reinforcement strips for each joint. I think it looks cool in a functional sort of way and I believe it serves a purpose.

[Alan Carruth]

I always reinforce the joints with a cross grain patch. Modern glues may be strong enough and all, but I'm all for the 'belt and suspenders' approach on something like this, where it's easy enough to do, and won't hurt anything if done right.

Note that it is possible to do it wrong. A violin making friend of mine once pointed out that when a crack is repaired it's normal to glue a line of studs in to reinforce it. He has seen a lot of cases where there's a new crack along the end of the line of studs, which are too stiff. He's also seen studs come unglued; again, because they're too stiff the move with the wood they're glued to and peel off. He has never seen a broken stud. They're always stronger and stiffer than they need to be.

A couple of years ago one of my students re-built an English guittar from ca. 1780. When we removed the three-piece back it had wood cross patches on the glue lines that were about 8-10 mm wide and so thin as to be practically transparent. They had held (with hide glue) perfectly, and there was only a hint of a crack at the end of one in one small spot. BTW: that instrument had an X-braced top....

[redir]

This is another one of my guitars and I have always found it interesting. Perhaps this method was a way to avoid the crack at "the end of the studs."

IT's probably a good idea to taper any sort of back strip to zero along the edge too.

[merlin666]

Originally Posted by Glen H

If you plan to have an inlaid back strip between each piece then typically you would use a reinforcement strip inside. If none then some will omit the reinforcement. I normally don’t inlay a strip on my back but still do the reinforcement strip on the inside. If it were my three piece back I’d take the extra couple of minutes and add the reinforcement.

This. And I would add that a three-piece back without inlaid strips to separate them visually just hurts they eyes. And don't say that people never see or don't want to see a guitar back ...

[gtrboy77]

Originally Posted by John Arnold

If the wood lacks an inch or less being wide enough, I would add wings on the lower bout. Ideally, these wings can be made from the same piece, cut from the waste area in the upper bout. That way, the color and grain match, so that the wings will not be noticeable.

That’s basically what my dilemma comes down to; being an inch or two short on the width. I’m glad you brought up gluing on wings on the lower bout. I hadn't even considered that. That’s a great idea, if I can get it to match.

[Carey]

Originally Posted by gtrboy77

That’s basically what my dilemma comes down to; being an inch or two short on the width. I’m glad you brought up gluing on wings on the lower bout. I hadn't even considered that. That’s a great idea, if I can get it to match.

I've had good luck doing it the way John Arnold suggests: taking a piece
from the same-side upper bout waste and moving it down and out on the lower bout wings. It's sometimes necessary to re-angle the joined area a bit on the added piece to get a good match, in my experience, but the reflectance (?) will be similar because the runout's usually going the same way.

[gtrboy77]

I wonder if people have done the same with tops as well, I mean gluing on “wings” on the lower bout. I do remember reading in another thread that people have done multi-piece tops successfully, so I guess it’s likely been done.

[printer2]

Originally Posted by gtrboy77

I wonder if people have done the same with tops as well, I mean gluing on “wings” on the lower bout. I do remember reading in another thread that people have done multi-piece tops successfully, so I guess it’s likely been done.

I have a top and back I made each from seven pieces and I think John Arnold has made a guitar with even more.

[phavriluk]

Multi-piece tops...I've never seen a guitar that didn't have a multi-piece top...

[Alan Carruth]

I saw an 1844 Panormo with a one-piece top once, but they're certainly rare.

[printer2]

Not good pictures, I had my tablet in the car and it does not have the best camera. Mind you not the best guitar. I saw this at a thrift store today and had to get a couple of pictures of it.





The top is 1/4" thick, did not even check to see if it had bracing. It made some sound, certainly not worth the $99 they were asking for it. 16 piece top, did not bother counting the sides.