www.KitGuitarsForum.com

Skarsaune wrote:Have to be an epoxy, I’d say.

I’m not volunteering. No time for this, can’t even get my builds done.

Nope.

Never mind that spare set of Mahogany over there.

Nope. Not volunteering.

:-)

I've got a pile of plates 6" tall. I apparently love to design guitars and collect the parts. I wish I could buy some extra days in the week.

^^^ Let's see what Diane comes up with for sure!

Diane Kauffmds wrote:I might be interested in experimenting with this top.

Couple of answers, I made the outer edge thickness (.080) 2mm as original and the inner between brace panels on this version .030 with the "isogrid" panel stiffeners .080 (weigh saving stuff) The braces are .050 thick x .375 high. The board is flexible and weights 400-435 grams. Which will get lighter next version. The board machining starts flat, curls concave when material is removed from the underside, Then I straighten it by hand to get to flat again. The soundboard is installed without a "dome" and when the strings are tensioned, it creates a .100-.080 doming from the string pull.
This versions' thicknesses are a raw guess, and the brace positions are derived from the Geo.Luthier supply drawing. (1914 Martin soundboard) Next version will be lighter
The "Tap Tuning" is a deep gong with long decay duration (i don't know the frequency).
Before the first one was made, the luthier said "it won't work" he was astounded when he first heard it plugged it in. So have other master Luthiers.
The 6061 t6 material Vs wood differential expand/contract question is moot. It provides a stable base for everything else to attach to.

Keep up the questions, I think they keep me motivated.
Thanks,
BrianO

Have you thought about trying a different alloy? (2024,maybe?)

MaineGeezer wrote:Have you thought about trying a different alloy? (2024,maybe?)

Yes i have, 6061 t6 is an easy plentiful, cheap choice About $32 per, with a certificate of quality.
So i used this first.

2024 is very soft and is what the Apache Chopper is made from, soft for vibration (stress crack) tolerance. I forgot the heat treat condition Very "gummy" to machine.

The harder 7075 and lite lithium aluminum's would be the best choice. $$ more $$
I would really like to do one in magnesium like the bridge.
The weight can be controlled by machining thinner or thicker where the metal is needed.
I have machined reliably to .035" And have the machining down to 1.25 hour.

I am stocked with tops because i do not build the guitars.
And need a luthier to complete the assembly.

Are you sure you have the characteristics of 2024 right? I've always found 2024 harder and less gummy to machine than 6061. It does cost more though. 7075 of course, is big bucks compared to 6061. I have no experience with magnesium , but it's an interesting idea.

One thing isn't clear to me: are the braces machined as part of the top, or are they glued on?

MaineGeezer wrote: I have no experience with magnesium , but it's an interesting idea. Mag will cut like walnut, so nicely
One thing isn't clear to me: are the braces machined as part of the top, or are they glued on?

2024 "O" condition Wing Spars AAH

Integral, monolithic, one piece.
This is why our rockets are flying,
this is from the 1960's rocket parts machine shop stuff

Hey i just adapted this to a soundboard, that's all..................
I was on a tour of Taylor and the idea struck me when i saw the inside structure of their soundboards Great tour.!!

Here is the story of a replica of a 1935 Bugatti, one-of-a-kind, that went missing. The replica, like the original, had a magnesium body. They said they had to be extremely careful cutting the material because it can start on fire from the friction

https://www.motorauthority.com/news/112 ... esium-body

Be careful out there

Ah! That's the difference. My only experience has been with 2024 T351, if my memory is correct. Anyway, it wasn't O temper.

Experimental top intro, Follow up.

I want to see this idea expand and here is a Kickstarter link to peruse.......
You will see most is the same as this thread.
The new designs are on CAD (not machined yet)
like the scalloped brace OM (cad plans from Dave, thanks),
and the GG Fan Grid Bracing, The "Crutch" bracing.

The video soundtrack is the actual two instruments in a home studio.

Please take a look and you can directly message / comment to me here.

Thank You John, Diane, Dave, Maine Geezer and all kit builders and experimenters.
Brian O.

https://www.kickstarter.com/projects/91 ... n=e5bc2e03

I've told everyone that I have one of these tops and YES! I've started the builds.

I'm building 2 dreadnought guitars, out of woods from the same billets, mahogany back/sides, mahogany necks, adi top on one and the aluminum on the other.

I'm starting by spray painting the aluminum top; I'm going to burst both builds, so they look as much alike as possible. The aluminum top is undercoating. I'm planning on finishing the burst this week.

I have 4 old Gibsons on my bench right now that need attention. I hope to bend sides in the next couple of days.

In the end, I have several professionals that will play both extensively, and give opinions and 3 universities that are willing to compare the wood vs aluminum via sound engineering equipment, for a more objective opinion.

I've had the top for almost 2 years now, but I'm woefully behind, between 2 shoulder surgeries, then playing catchup in tbe shop.

So, please stay tuned. Answers are coming, not only for workability from a luthier standpoint, but sound and opinions.