Last time, we talked about the Asymmetric Trapezoidal Neck Design. That was back in February! Since then, we’ve endured significant setbacks, but time moves forward, and we’re finally back on track.
Incremental steps. Now, I’d like to introduce a major design change for the Thor Mark III body. The entire middle section is once again a solid piece of maple, wrapped in carbon fiber—reverting to Thor Mark I’s original design. For added stability, and borrowing from acoustic-guitar construction techniques, the body frame now incorporates kerfing: 14 mm maple lining strips cut with a series of small slots (“kerfs”) that allow them to flex and follow the guitar’s shape.
This addresses a key stability issue with Thor Mark II. The new construction is exceptionally stable: the kerfing is laminated on both sides with carbon fiber, creating a remarkably stiff structure. We tested it under extremes of humidity and dry conditions, and the body held its shape perfectly.
The pickups and sustain drivers are now mounted from the top rather than the bottom, reducing routing and keeping the middle section as solid as possible. Combined with the carbon fiber lamination, this results in a significant increase in overall rigidity.
The middle section looks like a big piece of maple. Won’t this make it heavy, and defeat the benefit of the carbon fibre?
I suppose you mean the lightweight benefit of carbon fiber. It’s always a balance (pun intentional). We use a laminated CF-Hardwood Maple/Wenge/Ebony neck. A very light body will make the guitar neck heavy. The center of gravity is at the neck-body joint. This configuration still gives me a good balance in terms of weight distribution.
P.S. I’ve established early on that I do not want extreme lightweight, as I once did. Too heavy, and it’s a pain to use and lug around. Too light, and it starts to look flimsy and cheap.
That makes sense. Do you have a target weight for the new design of Thor with the trapezoidal neck?
Also I’m interested in how the materials will interact, and it’s not something I’ve looked into before. Hope you don’t mind if I ask a bunch of questions.
I guess the timber will expand and contract with temperature change. Over a long time, will that cause repeated stress on the carbon fibre? Could it eventually fatigue the fibre/matrix? Does the carbon fibre wrap need to be watertight to stop moisture from increasing the timber expansion? Does expansion only affect one direction of the wood grain?
Do you have a target weight for the new design of Thor with the trapezoidal neck?
I expect it to be the same as before. Around 2.5kg.
Over a long time, will that cause repeated stress on the carbon fibre? Could it eventually fatigue the fibre/matrix?
No. CF can flex a bit, actually.
Does the carbon fibre wrap need to be watertight to stop moisture from increasing the timber expansion?
CF+epoxy is watertight. So yes.
Does expansion only affect one direction of the wood grain?
Yes, along the width.
Thanks Joel.
I have a PRS S2 Mira semi-hollow which weighs just over 2.6kg, and it does feel like a nice weight.
It’s interesting that flamenco guitars can weigh as little as 1.25kg, and they don’t feel at all flimsy, even when using percussive techniques.
My theory is that the psychology here is how people are accustomed to something. It’s subjective. Electric guitars are historically heavy and “solid.” Anything that deviates from that significantly can be taken negatively. Of course, weight is also an issue.
OTOH, flamenco guitarists are probably accustomed to lightweight acoustic guitars.