Official Luthiers Forum!

So like I said on the other thread, this challenge got me inspired to look back at a project that's been going through my mind for a while. It's going to be as weird and original as I can possibly make it! That's the 'new' part I guess.
I have a cheap old guitar that's falling apart that someone gave me for free and I'll be using the tuners off it for the 'old' part. I might even go with a vintage-look hand rubbed sunburst and a bit of light distressing, if that counts as old too .
For the 'local' part, I still have some nice bits of a pear tree that was cut down in my parents garden that I might use in an inlay somewhere.
For the 'pick 2' part, it will be a parlourish size and shape and it will be practically free apart from a few bits and pieces.

Top: WRC, offcut from a uke project (Ok you could say the uke project was an offcut from this, in which case it cost about £12)
Back and sides: Mahogany £10
Neck: Will be a laminate of something, haven't decided yet. Most likely an offcut from work, so free.
Fingerboard: Ebony - it's one I had lying around, probably cost about £20
Tuners: Reclaimed, free
Lining blocks and bridge: Panga panga, £10
Carbon body brace: £15

Total: £67 or $97 (hmm not so free after all)

So the plan is for a guitar with no soundhole or sideport. Instead the top and back will be suspended from the sides by the lining blocks, with the gaps between forming the soundhole. Also I'm going to try doing an adjustable neck with no metal fastenings at all, just sliding dovetail wedges! It could be a total disaster, but that's what makes it fun Oh and this will be my first attempt at a classical guitar.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

This is the plan I drew up a while ago. The neck joint is wrong and it doesn't show the edge holes, but I think it's pretty much how it will look. Sorry about the blatant Matsuda rip-offs! I'm just building for myself and won't make any money off it.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I've been trying to work out a bracing scheme for this, which is tricky as there's no soundhole. Any opinions on this? The fingerboard will be elevated, so there'll be no downward pressure on the upper bout, only compression from the string tension.
I haven't really got a clue about classical bracing. I'm just going off pictures I've seen.
Oh and there'll also be a big carbon tube between the head and tail blocks.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I'm way out of my element with classical bracing but I would think that with out the fretboard pushing down on the top and no soundhole making a big weak spot right where the neck torque tries to compress the top into the soundhole, you would be able to get away will less bracing. I'm not sure what "less bracing" really means. I'm just pointing out that you have removed two structural problems facing typical upper bouts.

_________________
Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Good point. I might be able to get away with just a few full length longitudinal braces to counteract the torque of the bridge.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I'd go with carbon tubes connecting from headblock near the soundboard to waist near the back.

That's all. No other bracing needed anywhere. All done by graduating the plate thicknesses.

Seriously none at all?! That'd make me very nervous! I was just looking at your coral snake build and wondering how you got away with such little bracing.
What sort of thickness would you do the top at? This has a 13'' lower bout and 18'' body length.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Hmm, on second thought, I think you should go with some bracing. That's just a little too much active soundboard area for the braceless style (would be too heavy unless you do a double top). But you could put a big cross brace around the waist to section off the upper bout from the active area, and then it would be small enough. So it depends on whether you're curious about the tonal effect of an active upper bout or not.

But the other thing is that I'm very skeptical of the rim soundhole concept, so I think you should test that separately from the braceless concept (try it with a single large soundhole in the side instead).

So then... how to brace? The pattern you have looks pretty good. I think the cross brace can be very small, since it's not performing its usual role of soundhole support. Or it can be big, to reduce the active area if you think that will work better (either way can certainly work... but I don't know which is better).

I'm not trying to dissuade you from your plan, but as a data point, when I cut the binding channels exposing the gaps in the lining, the resonance of the guitar goes totally flat, and then becomes resonant again when I glue in the bindings. Of course, I already have a soundhole in so maybe it is just too much area, but my suspicion is that all those little slots kill the air resonance,
Mike

Thanks Dennis. I think I'd prefer going lightly braced rather than braceless. I'd always be worrying about it collapsing otherwise. With the soundhole thing, I know it's a risk, but it's going to be a pretty simple build, so I won't mind too much if it doesn't work. And if I don't try, I won't know if it works or not!

I'm not going to use normal kerfed linings btw. They'll be individual blocks with an inch or so gap between each. I figure it can't be worse than those guitars with carved celtic soundholes with loads of tiny individual holes.

Sent from my GT-I9300 using Tapatalk

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Well I finally made the first tiny bit of progress on this. I've got the sides thinned down ready to bend and I've nearly finished converting my spare bed into a workbench! I miss my old workshop... (I can't really complain, as I work as a furniture maker, but it's not the same as having one at home)

Hopefully more progress to come soon

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

And we're up and running


The metal pipe thing is going to be a bending iron once I've got it wired up. It's a hollow aluminium tube stuffed with aluminium foil with a cartridge heater inside. I hope it works - I've heard cartridge heaters can burn out quickly if the heat isn't transferred properly. Anyone else make one like this?

The back and sides are actually the same colour - the sides have just been sanded.


Sent from my GT-I9300 using Tapatalk

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Looks like a good start, I can't wait to see it come together. I see you already have your mold made, I keep meaning to pick up some plywood to make a new mold but only think about it late at night when I sneak into the shop.

Let me know how the cartridge heater works. I use a charcoal starter bent into a hunk of heavy galvanized pipe. It works great but it doesn't heat up as evenly as I would like. The heating element touches the pipe at a few points which cause hotspots and the iron pipe doesn't conduct heat as well as aluminum would. It is heavy walled so once it gets heated up it is even enough but not perfect and it takes a while to get there. I bought a second hand child's aluminum baseball bat and one day plan to cut it up and make a new bending iron out of the barrel and a tight radius one from the handle. Cartridge heaters and aluminum foil was my plan so it would be nice to hear how it works for you.

_________________
Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Thanks for the input. Bending the sides is one of the next jobs, so I'll let you know how it goes.
I forgot about the mould. I started making it months ago when I first thought of the project, but it's still only roughly cut. I need to smooth it out and glue all the pieces together yet.
Thankfully my radius dishes haven't warped after over a year in storage. It feels great to get all this stuff out again

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Well attempt 1 at side bending was a bit of a failure. The bending iron works fine but the 'heatproof' matting I bought off ebay turned out to not be so heatproof and melted and started dripping everywhere after only bending 1 waist.
I do really like the sideways mounting though. It feels a lot more controllable than the vertical ones.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Ok that wasn't really a problem. I just removed the heat mat and clamped the pipe directly with the wood. It scorched it a bit but is fine.
Here's the setup:

I probably should box in that controller before electrocuting myself...

And the end result. I've never had such an easy time bending sides!


Sent from my GT-I9300 using Tapatalk

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

So you got quick even heat with the cartridge heater and aluminum foil! Great news. I have always just put my pipe in my metal vice. I should get around to making a better mount for it.

The sides look great, so does the shape.

_________________
Bryan Bear PMoMC

Take care of your feet, and your feet will take care of you.

Yeah! It heated up very quickly - I didn't time it but must have been a couple of minutes. The heat seemed fairly even, but as the cartridge stopped short of the end in mine, the end was a bit cooler.

Sent from my GT-I9300 using Tapatalk

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I've been thinking a lot about my rim soundhole idea, but I'm starting to have feelings for this guitar and don't want it to turn out crap, so I think I'm going to make it slightly more conventional after all! It'll have the soundhole split between front and back in the upper bass corner so you'll be able to see straight through it. Splitting the area will also mean it'll interfere less with the soundboard and have more vibrating area, plus doubling as a sideport.
Something like this:

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Aaand last update of the day! I really should have just put all this in one post...
Neck and tail blocks are in and I'm in the process of sanding the rims down to the correct radius. Mahogany is so nice to work with



Sent from my GT-I9300 using Tapatalk

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I'm a little dubious of the carbon fiber tube between the head and tail, it would have to fit really tightly to effectively transfer any load. I think it's a reasonable idea, with the end connections being a little problematic. I'm sure you can work it out. I'm anxious to see this guitar executed in wood.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon

Thank you, me too!
I have to say, a lot of my ideas comes from other luthiers, Todd Rose in particular for this one. He did a documented build on the AGF a year or so ago with very similar construction which seemed to work well for him. I may still change to waist braces instead though, as suggested by Dennis.
http://www.acousticguitarforum.com/foru ... =todd+rose
(Pictures are in the facebook link in the first post)

Nothing to report progress-wise. It's been a very busy few weeks!

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

I'm back out of hibernation! I haven't done anything at all over summer, but finally got back to it yesterday. The laminated neck blank is glued up and I finished sanding the rims ready for linings.



Yes that is birch plywood in the centre of the neck... The idea is that the cross laminations will reinforce the heel block. Plus I think it'll look cool! The rest of it is recycled mahogany and recycled beech - both of which used to be bits of furniture.


Just some random doodling on the workbench of the neck joint and soundhole. The thing that looks like a bow tie will be a tapered wedge that keeps the neck connected to the body. The tapering will allow you to fine tune the neck angle. Remember it's a nylon string, so there'll be a lot less string tension than normal.

_________________
"I am always doing that which I cannot do, in order that I may learn how to do it."
Pablo Picasso

https://www.facebook.com/FenskeGuitars

Just my thoughts, Peter, but the strip of ply will be a weak point of the neck. Ply is strong in sheet form, but very brittle when used in strips in strips as thin as the depth of a neck glue up.
As always, I might be wrong, and in this instance, I hope I am.

Alex

_________________
"Indecision is the key to flexibility" .... Bumper sticker

I agree with Alex, the crossgrain pieces in the plywood will not contribute anything to the longitudinal strength of the neck. I don't think it will be a problem with nylon strings.

_________________
A man hears what he wants to hear, and disreguards the rest. Paul Simon