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plectra1.3 02-06-2019 07:25 PM

Aluminum acoustic guitar
 
Hi everybody, I'm new to this forum so I hope I do it right.

I am in the process of building an all aluminum acoustic guitar but I don't know what thickness of material to build the body out of. Should it be the same thickness as that for a wooden guitar? (2) Should I brace the same as wood?

If anyone has done this before and has some answers they'd be willing to part with I would be very grateful, Thanks.

ChalkLitIScream 02-06-2019 07:29 PM

Im no builder, but even I know that builders thickness different woods differently.

An aluminum guitar is going to sound much different for sure, and Im also sure youd need to tweak much of the build.

JonWint 02-06-2019 08:03 PM

Quote:

Originally Posted by plectra1.3 (Post 5972186)
Hi everybody, I'm new to this forum so I hope I do it right.

I am in the process of building an all aluminum acoustic guitar but I don't know what thickness of material to build the body out of. Should it be the same thickness as that for a wooden guitar? (2) Should I brace the same as wood?

If anyone has done this before and has some answers they'd be willing to part with I would be very grateful, Thanks.

I'd like to build one some day. Maybe wood B/S and alum. top. I'll try 3003 in 0.040" with no bracing and compare to the stiffness of a wooden top. I'll wheel a shape similar to that of a wooden top. If that is too stiff, maybe 0.032" with or without braces.

I know Martin had an alum top guitar but have never found any specs for it. I did research for info but never found anything of use.

tadol 02-06-2019 10:06 PM

Id look at resonator guitars for inspiration, and figure that aluminum is a completely different material than wood, and about all you can take from traditional guitar building is the shape -

bostosh 02-07-2019 05:35 AM

done it already and it sounds good - secret project
 
"' If anyone has done this before and has some answers they'd be willing to part with I would be very grateful, Thanks. ""

Your Welcome Plectra

The Martin aluminum was glued to a wood soundboard. old patent

Sheet aluminum has no strength must be backed up by something.
Outer sheet skin and backup support inside, (done a lot of aircraft)

bostosh 02-07-2019 05:43 AM

attaching the braces
 
Quote:

Originally Posted by JonWint (Post 5972225)
I'd like to build one some day. Maybe wood B/S and alum. top. I'll try 3003 in 0.040" with no bracing and compare to the stiffness of a wooden top. I'll wheel a shape similar to that of a wooden top. If that is too stiff, maybe 0.032" with or without braces.

How would you attach the bracing to the top sheet?

Mooh 02-07-2019 05:48 AM

Quote:

Originally Posted by bostosh (Post 5972448)
How would you attach the bracing to the top sheet?

Weld.

I'd be tempted to do an archtop with a soundbar.

bostosh 02-07-2019 06:23 AM

OK i have witnessed welding on .062 sheet, (Cessna door cracks)
The top outer surface will suffer.
how about bonding ?
that is how satellites get lightweight
Why not machine it from a solid plate?

printer2 02-07-2019 07:02 AM

Forget welding, too thin. Glue would be best, look up aircraft construction. To be light enough to be a top you would mainly have a thin sheet top and the braces carry the load. Make a wooden top and load it down at the bridge plate and measure the deflection, do the same for the aluminum and adjust till you get the same deflection. Would it be ideal? Probably not but it gives you a starting place.

ruby50 02-07-2019 07:24 AM

Knew a guy years ago that was a welder with every conceivable certification. A test for one of those certs was to weld 2 cigarette liners together - those aluminum foil liners inside the pack.

Epoxy would hold the wood brace to the aluminum skin. Would you do deflection testing to pick the top material??

Ed

JonWint 02-07-2019 07:33 AM

Quote:

Originally Posted by bostosh (Post 5972448)
How would you attach the bracing to the top sheet?

I'd use spruce braces bonded with epoxy onto aluminum. Epoxy top to sides.

An 0.040" top with a shape would be stiff enough to withstand string tension with little or no bracing. English wheel would be used to shape about 1/4" transverse belly and fall-off to the end block.

Aluminum back and sides could be TIG fusion (or filler) welded but it would be a lot of work. I've built a couple cars with aluminum bodies.

fazool 02-07-2019 07:49 AM

Before undertaking this "blindly", I suggest spending some time learning about
aluminum and wood and how they compare.

JonWint 02-07-2019 08:35 AM

Looks like it has been done before. Found these photos some time ago.

[IMG]https://i.imgur.com/10zeHOP.jpg[/IMG]

[IMG]https://i.imgur.com/CwpOHo7.png[/IMG]

ruby50 02-07-2019 10:26 AM

Since there is no humidity reaction, would you have to dome the top? I think you could leave it flat like a uke and that would make the neck geometry SOOO easy

Ed

JonWint 02-07-2019 11:19 AM

Greater the dome; greater the section stiffness. Would also resist the tendency of the area between the bridge and fret board from going concave.


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