Many guitar aficionados will have read about various polymer and carbon fibre materials that have been used in guitar building – or even had a chance to play one made this way. These compounds mimic many of the best qualities of wood, but absent the susceptibility to heat, cold, and moisture that has plagued owners of fine instruments for generations. Touring musicians have been quick to embrace these novel instruments, due to their durability and replaceability as compared to highly valued vintage pieces.
What Eastman is doing with their Double Top guitars is taking advantage of the strength and durability of the Nomex material, and sandwiching it between two layers of wood. They start with a spruce plate that will serve as the bottom of the guitar top, and rout out a channel into which the Nomex sheet will be inlaid. Then, another piece of spruce is laminated onto that, much like a traditional guitar top, but thinner.
Students of steel string guitar construction know that the trick to creating a loud and responsive instrument lies in making the top as thin as possible, without going so thin as to invite damage over time. This is the reason why there is so much discussion about the top bracing used in acoustic guitars, as different systems allow the thinner tops to vibrate in different ways, accentuating certain frequencies over others.
Using this honeycomb material, Eastman believes they have found a way to make a thin and rigid top that will vibrate with all the characteristics that guitarists demand. Nomex itself isn’t strong enough to be suitable for guitar components, but reinforced with wood – or being used to reinforce wood – gives it a chance to shine in this arena.
The primary industrial application for Nomex is in fire retardant clothing, and for circuit boards or other applications where high heat resistance is important. Experiments using the material in architectural setting for its acoustic properties have been very encouraging, and other luthiers have utilized this sort of lamination for classical guitar tops.
Eastman is currently offering three Double Top models, a dreadnaught (DT30D), an OM style (DT30OM), and a cutaway (DT30GACE). All three use solid rosewood for the back and sides, with mahogany necks and ebony fingerboards. They have a retail price between $2,500 and $3,000.
In this video, an Eastman rep at the NAMM show explains a bit more about these guitars.