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Greetings everyone. I went through a lot of the posts on double tops and didn't see too much information about this so I apologize if it has already been discussed. I have built a few double tops in the past with nomex, but I have heard a few things about its longevity that alarmed me (I didn't do much research on my own so it may not be accurate). I remember at one point seeing someone using an inside layer of drilled out wood that mimicked the effect of nomex. Has anyone tried this as opposed to nomex and what were the results? What would be the downside to this method?

I think you need to get a hold of Peter Marreiros of Cornerstone Guitars, PeterM here on the forum. I believe he does a fair amount of that.

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Jim Watts
http://jameswattsguitars.com

I made a double top figured redwood last year. It is well reviewed by all who play it. Below is a thread where I talk about how I accomplished it.

I decided to try it base on a beater Washburn beach guitar I had. It was a dread that sounded OK, but the top was laminate or what looked like Formica and spruce. I thought if they could make a dread from Formica that sounded decent, why couldn't I make one with figured redwood.

viewtopic.php?f=10101&t=22323&p=307075&hilit=redwood+epoxy+lutz#p307075


This thread shows the final product and has a very short Youtube link.

viewtopic.php?f=10101&t=23108&st=0&sk=t&sd=a&hilit=redwood+baritone

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"An adventure is only an inconvenience rightly considered. An inconvenience is an adventure wrongly considered." G. K. Chesterton.

Hi Kristopher

The method you mentionned was used by Frederich Holtier, but I think he is now using nomex.

I make my double tops with the inside layer made of balsa and cedar, instead of nomex. I have been working on that method for about 9 months and made 4 guitars this way, and I am pretty happy with the results. Since it hasn't been even a year yet, I cannot comment on durability, but in an article by Randy Reynolds in GAL, he suggest that there is no reason to believe that either the nomex or the adhesive (epoxy in his case) should not last for as long as a traditional guitar.

Cheers

Pat

I have been using a solid core all wood honeycomb method for almost 4 years. My own design and has worked flawlessly on more than 7 guitars now.

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Peter M.
Cornerstone Guitars
http://www.cornerstoneukes.com

Thanks for your responses...the idea makes sense to me, but was curious as to why more people aren't using this method. I really like the idea of using natural components. I was using balsa/carbon fiber for lattice for years, but switched to all wood bracing for acoustical purposes. Do you find your method is very labor intensive and what do you like better about your guitars over the composite counterparts? Any pros/cons would be helpful, especially as far as process is concerned.

End-grain balsa has a good history as a composite core material. It doesn't have the same stiffness/weight ratio as aramid honeycomb, but it could do the trick. Aramid fiber is sensitive to UV and to acids, but it won't be exposed to either of them in this application so I don't see any reason for it to degrade.

Making a double top, as a composite structure, isn't trivial. Too much glue turns your composite panel into a laminate panel, so you have to be careful of using minimal adhesive. There is an argument to be made that maybe a well made laminate panel might sound good, too, though! So any composite-style double top is labour intensive. Having seen it, I can say that Peter's method makes the regular double-top method look like a real labour saver!

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Bob Garrish
Former Canonized Purveyor of Fine CNC Luthier Services

Bob said:



That's of paramount importance. Since my all wood middle layer is solid (no holes as with nomex or a perforated solid material), it requires more adhesive as the whole surface is in contact. I use System Three T-88 epoxy and I have got it down to about 33gr of it. In the case of epoxy, too much would just bring the weight up and negate most of the advantages of the double top, while too little would make the top collapse as the layers would separate under tension (been there, done that...). My goal is to bring it down to about 30gr.

Cheers

Pat