Explain for me please.

I watched again the beautifully scripted and shot documentary on Greenfield guitars. He laminates his sides as some do here but not the backs. This makes absolutely no sense to me in terms of construction and conservation.

What I do know is my 1970's Yamaha FG150 was entirely laminated top, back and sides but its was an amazing instrument. However many laminated ukes sound very thin - the Romero (HMS documentary I think but cannot find it in the YT play list) one being a case in point with it's 'veneer braced' front. Loud but no character.

So I can understand conservation issues, see the value of the construction method in terms of stability and consistency. I just don't get how those layers of glue between the laminations which have been historically and actually despised for their sound dampening qualities can now be extolled with virtuous applause.

Am I being awkward about this (an it won't be the first time I and YOU know )or am I still in the Dark Ages?

The theory is that laminated sides are quite stiff and help the top work with an active back. If you laminated the back it wouldn't be very active. Possibly more effective with a guitar than an ukulele, especially a smaller one.

Yes. It's about making the sides/back inactive or rather less active. Trying to keep the energy in the soundboard rather than the back/sides acting as a 'sink'. Laminated backs certainly have a long history. They go back to virtually the very beginnings of the single 6 string guitar. In that case it was virtually always spruce laminated onto a more decorative hardwood. I've absolutely nothing against laminated backs and sides. Laminated soundboards aren't the greatest of ideas for very obvious reasons. Double tops and that Romero are obviously not the same as the usual cheap laminated soundboard. Whether you like the sound of those DT's or the Romero is obviously down to the individual. Not sure I do (but it might depend on the particular DT) but some people clearly do.

Yamaha does a good laminated guitar. The Godin line of companies makes good laminated sides and back guitars. They use, for example, cherry outer and inner layer with a cherry core. Cheaper guitar construction uses a very thin show layer and then the cheapest wood they can get for a core. But even that would not be so bad but they over build the guitar so that the back does nothing to contribute to the sound. The laminated side, or double side construction is done to give the top and the back a stiff platform in order to maximize the output from the top and back. The added mass of the sides help also. Unlike laminated guitars the two laminations with this type of construction has the lamination thicknesses thick enough to work as sides themselves. The back is solid wood as it is thought to have better resonance than laminated wood. I have not come across testing if this is actually true, it would cost more to build the back this way if you are using the same wood type throughout the construction. Maybe archtop builders have some data on the difference, laminated backs were not frowned on in that community.

The Australian Classical guitar maker Greg Smallman laminates his backs (it think they are about 5mm! thick- BRW with cedar core)- He presses them into a mold, so is not a simple slice of a sphere liek a typical back but more molded like a carved arch top back.

Been thinking about this all weekend. Gonna seriously do this next month when I can get my m8 to CNC the back press forms. I like the idea of having no braces in the back. Watch this space.

I love the way Pete is always thinking and exploring new ideas!

Pete Howlett said:

Been thinking about this all weekend. Gonna seriously do this next month when I can get my m8 to CNC the back press forms. I like the idea of having no braces in the back. Watch this space.

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As I recall, Taylor guitars make their GS mini model this way, i.e.no back braces, just a moulded laminated back.

Pete Howlett said:

Been thinking about this all weekend. Gonna seriously do this next month when I can get my m8 to CNC the back press forms. I like the idea of having no braces in the back. Watch this space.

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You'll still need the linings tho' to support the bindings..and you need bindings to hide the laminate or you could use posh wood and make the laminate look like bindings

Timbuck said:

You'll still need the linings tho' to support the bindings..and you need bindings to hide the laminate or you could use posh wood and make the laminate look like bindings

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Alternatively, I've seen another maker effectively do a 45 degree bevel around the inside of the sides and the back, so they mate seamlessly... But I prefer bindings!

Further on the back consideration: laminate backs will create a "reflective", rather than "live", style back. This is perfectly suitable for ukuleles.

I've a vintage Morena ukulele with this style of moulded/arched back sans bracing... It's light and loud - I like it.

Pete Howlett said:

Been thinking about this all weekend. Gonna seriously do this next month when I can get my m8 to CNC the back press forms. I like the idea of having no braces in the back. Watch this space.

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Do it- uke backs are too small to think about tuning the backs and a molded back looks cool.
However, Pepe Romero's skinned backs (outer wood with spruce inside and no back brace) sound good, but i,m just no sure of their longevity (same with the skinned tops with no braces).

I don't think there is much to be gained as far as sound goes, but they would be more work for sure.

I've fully worked out how to do it including making shaped laminated linings. My CNC is down at the moment and it will require using Aspire software which I don't have to do the necessary jig making. I do however have a friend who is willing to help me here...

As for taking more time? I think it will probably work out the same.

So here's the proposal: I intend to use a show face of 1mm thickness, a transverse core of the same specie of 0.5mm thickness and an inner skin of 'plain' wood the same as the show face of 0.8mm for the ribs and back. I have some lovely curly American walnut for this. Just need to scoop up some plain stuff off eBay for the inner face and some veneer. The back radius is going to be 8' spherical and not the 'pseudo' arch top pressed shape - I don't like this.

I'm going to use my super tenor/baby baritone design because I designed and created all the base drawings in my 2D program and built the subsequent jigs and moulds/forms using my CNC machine. The back press jig will be derived from my dish program and the rib press from my mould/form program. Did those two this morning - just have to prepare cutting regime for component parts and the subsequent g code for cutting therm. I have all of the materials for making the jigs, just need time - I spent 5 hours with my mate cutting MOP on his CNC for a pearl bordered commission - the kindness of friends and generosity of peers in this community is the stuff of legends.

So I will be back to report the progress.

And a picture or two? Need a little smiley of a dog looking up with tail wagging.

J.F. Custom said:

...Further on the back consideration: laminate backs will create a "reflective", rather than "live", style back. This is perfectly suitable for ukuleles.

I've a vintage Morena ukulele with this style of moulded/arched back sans bracing... It's light and loud - I like it.

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I have spent about a lot more time watching waves lap a shoreline and bounce and reflect and collide as I have spent making ukes, and from this I think that the smooth and rounded back could help the sound both in volume and tone. I picture waves tripping over those bottom braces with reflections all over the place. Looking forward to hear how this experiment goes.

-Vinnie in Juneau