Thread: Piano inspired Acoustic Guitar

Hey Mike, you're kind of like a pioneer leaping into the unknown there, thats fan_bl##dy_tastic, I can't wait to hear of the results and a sound demo would be good too. I'm so glad to see your heart is still in it.

regards

Wal

Thanks Wal, I was about to throw in the towel but then the idea popped into my gray matter about the piano having so many strings and they don't seem to have the problems with the soundboards that I've read about with guitars. Seemed like it would be worth trying to use it's methods of construction in a guitar. If it works as good as the test board ( got my fingers crossed ) then it should sound good. If nothing else it got me motivated to go at it again. If I can find someone to record a soundtrack and not charge an arm and a leg, I will. Going to need someone to play it too because my playing skills are really awful. Might be awhile before it's complete, trying not to rush the finish which so far is coming up pretty well, except for a few pesky pores that don't seem to want to fill. How's your build coming? The last photos I saw of it with just a hand buffing looked awesome, can't wait to see the finished product.Mike

Great work there Mike, I like the bolt on neck for an acoustic idea.
With the laminated sides, how many layers, and do they alternate in direction, or run the same?
Is it french polish for the finish?
I agree with Wal ,you're a pioneer ,

Rob

Thanks Rob, The bolt on neck was easier as far as the construction goes but it's turning out to be a pain getting the finish in those sharp corners. I'm redesigning that to use a detachable heel block. The sides are three-ply, mahogany for the outer layers and a maple inner layer that is as thick as the two mahogany layers combined. The maples grain is 90 degrees to the mahogany. My theory is that since the vibrations travel faster with the grain, I can get more out of the back of the guitar. Don't know if that's going to help or not as I've only tested soundboards. I am french polishing, I used a combination of techniques to fill the grain on this one. I started with Timbermate, but found that the water in it reactivated the fish glue I used, just enough to leave a dark line at the glue joints. Fortunately, I was able to sand it off. I choked up the pores as much as I could with shellac, like you told me, let it set for 24 hours and sanded it almost to the bare wood, then used pumice to finish it off. Worked pretty well. I've been doing 3 sessions and then cut it back with a 1000 grit Abralon disc, lubed with mineral spirits. It's working a lot better than when I tried doing about 8 sessions and cutting it back. If it turns out half as good as your polishing, I'll be happy.

I love how stable this design looks. All the different avenues that can be taken and the things that can go wrong have pretty much kept me away from building acoustic guitars, but this looks like a great idea, very innovative. I fancy making one of these guitars one day:


so I might look into using something similar for the framework
Good job

Regards,
Miles

Miles, that's the way I felt. I tried a lot of different things and it seemed like most builders were trying to go as light and thin as possible. I was on U-Tube one day when a How It's Made video on pianos popped up. After taking a look at it, I started wondering if it's methods of construction could be applied to the guitar. That extra frame and the heavier neck block only add a little over a pound to the weight but sure adds a lot of stiffness to it. I plan on adding 2 more plys to the laminated sides on the next one and like I told Rob, I'm going to use a heel block that is detachable from the neck, to make the finishing easier. If I had a steam box I would have tried making the frame by bending it out of one piece of lumber, I'm sure it would be a lot faster. Good luck if you try it. Mike

Miles, I've been thinking about that guitar that you pictured and it seems to me you could adapt what I've done to that guitar, might need an extra cross brace on the frame near the sound hole. Have you ever played one of those? I've been trying to figure out how those extra strings are used. Mike

No, unfortunately I haven't played one before, but I would love the chance. From what I know it's a one of a kind custom job done for a jazz rock player by the name of John McLaughlin, but it wouldn't surprise me if others have had a go at making one. The idea of it is to sound like a sitar, so it has a scalloped fingerboard and the strings across the sound hole are sympathetic, so they vibrate when you play the main strings

Miles

Gday Guys,

Been a while since visiting the site,

Heartstrings,

You have hit on a style of guitar that Ernie Halron tried many many years ago, good on you for your thought's into this.
I have a very very old book somewhere that shows what Ernie tried to do in sketch form, I can't find it at the moment but I will keep looking for it as I think you may be interested in seeing this. I can't seem to find a lot of things after the move unfortunatey.

I recall that I think he actually worked for Steinway when younger or another piano company & from this his design developed?
I do know that he could not get the resonant frequency of the soundboard where he wanted it & after many years he finally gave up.

I believe it was his bracing idea that held him back.

Cheers
WayneW

Wayne, if you come across that imformation I'd sure like to see it. I tried a couple of other bracing methods before settling on the ladder bracing. It gave me more bass and sustain than the others, which is exactly the opposite of what I expected based on what I've read on it's use by other builders. The thing that I believe has made the biggest difference is the frame inside the guitar, it eliminates any flexing of the sides as the top moves. I'm working on a new top right now as I pressed to hard around the soundhole while polishing and cracked it. I'm going to change the angle of the grain of the top and see if I can get a bit more bass. I'll keep you posted. Mike

Smallman's lattice braced classicals have a plywood internal frame to support the top.

Originally Posted by kiwigeo

Smallman's lattice braced classicals have a plywood internal frame to support the top.

Yeah, I came across that when I was looking at methods others were using, but not having worked with lattice bracing before I tried a few other more traditional bracing methods to try and get the same result. What I'm hoping to get is method that will allow me to build guitars with a consistant sound with the same size braces and top thickness. I'm trying to keep the bracing simple and to contain as few of them as possible. I might be all wet, but I figure since every piece of wood is different, the fewer the parts, the easier it will be to build many guitars of the same sound. You've built a lot of acoustics Martin, so your opinion means alot, do you think I'm spinning my wheels? I'm trying to get more punch out of the bass too, running the grain of the top at a 50 degree angle helped, don't know why. I'm thinking of trying a top, half mahogany and half spruce, saw one on the net built that way. Have you ever tried a top made that way? Thanks for the inputMike

Originally Posted by Heartstrings

You've built a lot of acoustics Martin, so your opinion means alot, do you think I'm spinning my wheels? I'm trying to get more punch out of the bass too, running the grain of the top at a 50 degree angle helped, don't know why. I'm thinking of trying a top, half mahogany and half spruce, saw one on the net built that way. Have you ever tried a top made that way? Thanks for the inputMike

Hi Mike,

No I dont think youre spinning your wheels...your design looks interesting. Smallman's plywood frame as I understand it is a way of freeing up the top and the way I see your creation....youre achieving the same thing with your guitar.

My initial thoughts on running the grain of the top at an angle...you could be affecting the overall stiffness of the top which in turn could affect bass response.

The half mahogany half spruce topped guitar sounds like one of Ervin Symogi's creation. If thats the case then I suspect he did it more for asthetic reasons than to change the sound of the instrument.

Cheers Martin