Double Top Guitars
Double top guitars are a relatively new type of classical guitar top that is being used by a number of instrument makers to provide greater volume and tonal characteristics over a standard traditional classical guitar. The photo below shows a guitar top that has had a cavity routed out. In this cavity the Nomex will be glued in using a vacuum press and a special type of glue. The tops of these types of guitars can have three layers or two layers. Damian builds his double tops with two layers only and routes the cavity for the Nomex. This method of using only two tops saves another top from being used or wasted (i.e. going up the drum sander as saw dust).
In the photo below you can see the Nomex that has been glued into the cavity of the guitar top. The thickness of the Nomex is 1.5mm with the thickness of the cedar top in the picture below being 2.1mm. The cavity is 1.5mm deep to match that of the Nomex.
The photo below shows the top layer being glued to the other layer above which has the Nomex insert. The thickness of this ‘skin’ that is glued to the above part is 0.6mm. Before this skin is glued onto the above section it is sanded to specific thicknesses in certain areas to graduate the top and tuned.
Once the top comes out of the vacuum press it is treated and braced like a traditional classical guitar. The tops are very strong with the Nomex and can be braced a little lighter than traditional classical guitars. The Nomex is incredibly light, this coupled with lighter bracing and a lighter bridge ( Damian builds his bridges for this model out of Paduak which weighs only 12 grams) make for a guitar with a more immediate response, greater volume and a bigger tonal range when compared to a traditional guitar. Double top guitars ad an additional 2 days to the build time and require two guitar tops (as mentioned some makers use three) and the Nomex. Damian builds his double top guitars in a style similar to Matthias Dammann who was the original builder of this type of guitar.
Some guitar makers use the Nomex across the entire soundboard from the bridge and around the sound hole. I don’t do this as it makes no positive difference to the sound and it makes routing the purfling channel more difficult and any future repair work if the instrument is dropped or knocked heavily incredibly difficult. As I do a number of repairs of string instruments I build in to all my instruments the ability for them to be fully repaired as they can be taken apart by a skilled experienced luthier.