Double Top Classical Guitar - Redwood/Nomex/Sitka Spruce/Curly Black Walnut, Part 1

In an earlier post, I talked about how I replaced the top of a guitar I had on hand with an all-wood double top as an experiment. The new top was an improvement, it was very loud and strong, but its voice, to my ears and aesthetic, was lacking in beauty. I mentioned this in a text to a guitar maker I know in Brazil, he replied that he had made a similar double top and found that it "lacked resonance".  After playing the guitar for several weeks I made the decision to replace the top yet again, but this time with a “standard” double top that has a honeycomb Nomex core. The top is redwood and the inner veneer is Sitka spruce. Here is a link for more information on double top guitars.

Here is a jig I made from MDF, I wanted to have the main area of the lower bout to carry the Nomex. At this point the entire top is about 2.7mm thick. The top is on a vacuum platen that I made, the air is removed with a shop vacuum, this way the top won’t move or get pulled up into the router bit.

The feeler gauges in front of the jig represent the final thickness of the routed area, about 0.7mm.

Here is the top after routing.

The jig then goes on top of the honeycomb Nomex material…

and I careful cut the material with a chisel.

The honeycomb material was glued onto the top using a polyurethane glue and a Roarockit vacuum bag.

I used Sitka spruce veneer to cover the Nomex and redwood top. After the glue has set, I sanded down the honeycomb material level with the top, graduated the top so that after I glued on the Sitka spruce veneer I could graduate the thickness of the tops edges to about 2.0mm, the area under the bridge to about 2.5mm and most of the upper bout to about 2.7mm.

I went with a different bracing pattern this time, it is loosely based on bracing pattern used by a guitar maker in Granada, Spain, whose guitars I greatly admire.

Stay tuned for part 2, when I will share how I put the guitar back together! 


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