Hollow body with a difference

[rocket]

In the past when i've built a hollow body electric arch top i've either carved the plates and left them a lot thicker than i do with an acoustic or used a laminated construction, trouble with the laminated plates i've bought is i don't like the arched profile,,, these two scenarios coupled with heavier bracing and top mounted pups usually deal with the feedback problems arch tops have when high volume is needed.
Some builders use a solid block inside the body to combat the problem and others use heavy bracing and struts between the plates.
On this build I've adopted something from both of those methods and come up with something of much lighter construction but still effective in the anti feedback stakes and hopefully adding some sustain, two full length full width, timber / cf ribs, 4 mm thick .

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Cheers

Rod.

[demonx]

Looking pretty fancy so far!

Should be a stunner when it's done.

[slowlearner]

Man, that's very impressive. Should be lovely and light to play too.

[jeffhigh]

Do the ribs contact the top, or are they just breaking up the air resonance?

[rocket]

Jeff,, the ribs are glued into a groove in both the plates, when i carved out the plates i left enough meat to run a4.25 groove.
Rod.

[jeffhigh]

I was looking at the picture of the soundboard wrong, looked to me like parallel braced capped with CF when it was actually grooves.

[blackalex1952]

I would like to postulate the following speculation. Please note that it is not a judgement or an opinion, it is merely a possibility to be considered...
A laminated soundboard and back would not have the kind of sensitivity to changes in moisture content that solid timber plates would have.
A laminated soundboard and back that has a solid sustian block as in a Gibson 335 which connects the top to to the back will not have the kind of sensitivity to changes in moisture content that solid timber plates would have with the same construction, as in a Gibson 335.
Solid arched plates dome and flatten out as the moisture content varies.
The construction in your photo divides the top and back plates into three separate areas for each plate, which can move with changes in moisture content and fixes the plates at the baffle points lengthways along the grain of the quarter sawn timbers.
Therefore it is possible that the soundboard and back could be subject to cracking at the points where is is glued to the braces and baffle.
I wonder if that is one of the structural reasons why sustain blocks which run the length of a guitar are not often seen in non-laminated guitars? Perhaps you or others reading this thread have seen similar instability in non laminated sustain block construction?
I am also wondering, if this design turns out to be successful, if the timbers and their weight in the baffles can be varied to influence tone attack and sustain? I think there is probably a reason for spruce sustain blocks and not heavier wood, and that the density of the spruce has an effect on the guitars sound...Beautiful precise workmanship, by the way!

[routout]

I like when people do different things which may lead to more experimental adventures in future builds ,thank you .

[rocket]

All fair comments,i consider that the construction method is similar to the solid block method on regards to parallel to grain connection, I've built several semi hollow/carved jobs and have had no issues with stressing along the grain, i feel that this method will also give the plates a more even exposure to atmospheric conditions than the solid block method so maybe that's a plus!
Rod.

[rocket]

Making a bit of progress with this build, got the neck bolted on, silky oak with bubinga f/b blackwood veneers, bridge base and pup mounts are matching Otways blackwood, have applied the first session of grain fill.
I intend to finish in Mirrotone 3220 but i want to finish the top in an acrylic solid colour, i'll have to do some homework on compatibility because although the two will be done separately the meeting point will be at the purfling line around the belly, not carved in stone yet but that's what i have in mind.

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Cheers

Rod.

[kiwigeo]

Nice work Rod.....as usual

[rocket]

Yeah thanks Martin,,, and you're not looking too shabby either, your multi scale OM is a real stunner, glad you overcame the tuner hole dilemma re the f/p

Cheers

Rod.

[routout]

That's a really nice clean look on the edge binding just the rite amount a nice break from both pieces of wood.

[Jason Rodgers]

Super cool all around. The bracing could be seen as a variation on the Gretsch "trestle" bracing. Worked for them.

[Lex]

Very Clean and Neat Rod, I also like that Black wood showing nice figure, I assume it will look fantastic under a finish.

Cheers Tod

[rocket]

Thanks Tod, yeah I think the grain fill gives an indication of what it'll look like .
Cheers

Rod.

[rocket]

So I managed to sort the finish out on this,
Mirotone nitro on the top and then go over the lot with 3220. Quite happy so far.
Cheers

Rod.

[rocket]

A bit of Otways fiddleback Blackwood at its best
Rod.

[johnparchem]

Wow, that guitar is looking good. Very innovative design.

[rocket]

Finished

[56nortondomy]

That's turned out great Rod, does it sound as good as it looks?
Wayne

[rocket]

Of course it does Wayne

[kiwigeo]

Was wondering how this build was going. Looks like it turned out extremely well. A very nice looking guitar Rod....

[rocket]

Thanks Martin, i'll try to get a bit of a sound clip of it and post it on here.
All the best of the season,
Cheers,,

Rod.

[routout]

That is a very nice finish ,I got a thing about arch tops with a nice figure the binding just pops the whole lot out .