Designing and Making a Custom Archtop Guitar

by Guitarras Jaén Aug 4th, 2011

A few months ago a client came home to start talking about his guitar. He didn't want me to start working on it immediately; he simply brought me some drawings and some specs of what he was thinking. His idea was for a "concept guitar", which he calls "Maple and Water". Water is more obviously present at the inlays: at the fingerboard, he wants some leaves dripping water, and the drops finishing their fall at the tailpiece. The Maple should suggest water also, and he collected some photos of quilted maple that could be appropriate. The neck should be quilted also. I warned him that quilt is an effect that, when present, is only visible for flatsawn pieces, so it may show its quilt from its sides, but it will be more like flamed maple when seen from behind. The top was Spruce; given the concept, I suggested Bearclaw Spruce. This figure is different from the curls in Curly Maple because the "claws" are very local; so, a top may be full of bearclaw and then half an inch below it is rather plain. I have some wood that looks promising because it shows a lot of "worm" figure on its edges: 

You can see that the claws are very thin, so the look of the finished carved top is not very predictable. When the size of the blank is enough, I can take decisions to improve my chances of getting the best from it. This is the eternal problem for archtop guitars, because these desirable figures are not the only thing that may be waiting inside the thick wedge... many times, there are resin pockets and rotten or dark areas patiently waiting for years to be discovered. There may be external signs that may help to detect them, but some are well hidden.

I had to get some cello wood for the back and sides:

That is European Maple, with a very uncommon quilt figure. Quilt is much more common in other maples, but it is a rarity in this one. The man who cut the wood told me that he got 11 quilted cello sets from a small area of the tree. The rest was flamed maple, but only the lower part of the stem, as usual.

As this wood is not quarter sawn (otherwise the quilt figure does not show), its humidity content must be very low or it will be subject to undesired tensions after being glued to the sides. The reason is that flatsawn wood doubles the rate of quarter sawn wood when it comes to changing its width due to humidity changes. This wood was cut two years ago and it was kept in a very dry place since then. Its humidity content is around 9%, but I expect to move it down to 6% in a couple of weeks. This is easy in the summer, in this area of Spain!

The picture above shows a portion of the blank for the neck on the right, which will have 16 frets out of the body. This is quite uncommon in a guitar with 3 3/8" sides and a 18" body! I'll explain that later, anyway.

The sides were not difficult to bend. They show a heavy quilt figure, but they didn't fracture at the bending iron. I am sure that lignin and other chemicals in the wood make some pieces very different from others at bending... In this case, it was very easy. However, flatsawn wood has a strong tendency to cup, so it must be clamped in the mold firmly while still wet, until it's totally dry.

The side reinforcing strips are not glued yet. You can see that I follow the approach of Benedetto, using strips that go from the top to the back. It needs more work, but they protect the sides from extending cracks much better.

A few days ago I received a design from my client:

I'll have to work on the details, but I like the idea. I'll keep you posted!