Build #2 - This time an acoustic

wingcommander

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Man those sides look THICK! What's the thickness give or take?

Are you still planning on the cutaway as well? I'm very curious to see how it all turns out!

Cheers,

Alberto
I followed the generally used thickness from other posts on the form, so probably average.
Not doing the cut-away on this first build; I'll try it on the second build.
Different wood for the sides on the second build so hopefully it bends as easily.
 

wingcommander

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Tail Block​

Decided to make tail blocks out of a piece of Wandoo (a Eucalypt from AU) I could from old wool sheds down Albany (WA) way. I used my router levelling sled to get a piece about 20mm thick, and then cut 2 tail blocks about 100mm wide.

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I thought I’d follow the wisdom of the forum and improve my mould by adding some restraints for the sides. Similar to the ones on member comments I’ve made two turnbuckle clamps to hole the upper and lower bouts nicely to the mould.

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The previous picture shows the tail block already glued in place. Don’t know if it’s normal practice but I put a large radius on the tail block to match the curve of the mould. I probably could have gotten away with leaving it flat, but in for a penny, in for a pound.

Next I need to cut the neck blocks and glue them in. I’m assuming that the neck blocks are normally glued in as solid blocks, and the joint work is done later. I’m just a little worried that I’ll muck up the joint and have to start all over again.
 

Freeman Keller

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Tail Block​

Decided to make tail blocks out of a piece of Wandoo (a Eucalypt from AU) I could from old wool sheds down Albany (WA) way. I used my router levelling sled to get a piece about 20mm thick, and then cut 2 tail blocks about 100mm wide.

View attachment 1032881



I thought I’d follow the wisdom of the forum and improve my mould by adding some restraints for the sides. Similar to the ones on member comments I’ve made two turnbuckle clamps to hole the upper and lower bouts nicely to the mould.

The previous picture shows the tail block already glued in place. Don’t know if it’s normal practice but I put a large radius on the tail block to match the curve of the mould. I probably could have gotten away with leaving it flat, but in for a penny, in for a pound.

Next I need to cut the neck blocks and glue them in. I’m assuming that the neck blocks are normally glued in as solid blocks, and the joint work is done later. I’m just a little worried that I’ll muck up the joint and have to start all over again.
I put a slight radius in my tail block to follow the radius of the sides. As far as the neck block is concerned it depends a bit on the style of joint you plan to use but you can make the mortise either before or after the block is glued in place. For a bolted joint I think it is easier to cut the mortise before because then you can drill the bolt holes on a drill press and get them nice and square. A dovetail is easier to route after the body is all assembled but requires a jig.

I make the neck and body simultaneously so I can be fitting them and futzing around with the geometry as I build them. Here is a bolted M&T neck with its block before it was glued into the rim. When the sides are in place there will be a gap at the end of the tenon - the contact points are the outside edges of the neck heel
 

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wingcommander

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Neck Block​

Got a piece of wood to the right dimensions for a neck block. Decided I’d glue it in and do the inside work for the bolt after I work on the neck.

As an aside - On the subject of the neck I wondering about a truss rod. Is it still recommended for an acoustic guitar with only 14 frets to the body. I’ve seen on the forum the use of carbon fibre rods to add stiffness. Do you still need a truss rod if you have the carbon fibre rods? If I go down the truss rod path, is having the adjustment in the guitar body achievable for a novice?

Any way, I glued the neck block to the sides. There was a very minor amount of slippage by nothing too bad. I stuck sandpaper strips to my working surface and did a bit of sanding to get one edge reasonably level. I’ll sand the opposite side when the last face is ready to be glued on.

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Time for some neck work next.
 

Freeman Keller

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Two minor comments, Wing. First, most acoustic guitars do not have flat backs (or tops for that matter), they are more or less spherical in shape. It is somewhat difficult sanding that spherical shape into the sides and head and tail blocks. You can make a sanding stick with a curve in it or use a radiused dish, but should not be sanded flat.

As far as carbon fiber reinforcements and truss rods. CF is fairly new in guitar neck construction and certainly will make the neck stiffer. I used them for the first time (for another reason) on my archtop and they made the neck almost too stiff, 165 pounds of of string tension barely pulls any relief into the neck at all. I still installed a double acting truss rod, I think it is a good idea but you can make that call.

Classical guitars with their 80 or so pounds of tension normally do not have truss rods and frequently have the relief planed into the neck when it is being made and set to the body. My reasoning on a steel string is if I leave it out and need it later its a bit too late.
 

crazydave911

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If I went with the Carbon Fiber, it would be very light with a single acting trussrod like a Gibson. Just don't forget those trussrods have a bow with a curved piece of wood (usually hard maple) glued over the rod. Best piece of wisdom I (you) ever heard, "if you have upbow in neck tightening a straight trussrod is worse than useless, it's dangerous to the neck"
I have repaired MANY mandolin necks (which really don't need a trussrod in most cases) with a straight trussrod, generally tightened and broken. Digging them out is generally expensive if you can
 

oldunc

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Acoustics are a million times harder than electrics, listen to Mr. Keller, the guy really should write a book.
I've sometimes wondered about the connection between moisture and bending. It seems intuitive that wet wood would bend better, but I'm not at all sure that that's a major factor, dry bending is pretty commonly done. Certainly heat is the main thing, but wet wood will hold it better, and especially if you're working with improvised forms getting the wood tight to the form and secured before it cools can be a real problem; reheating the wood once it cools will not bring back the flexibility. I can recommend, from experience, against doing it outdoors in winter. It's a good idea to heat your forms in advance and keep a heat gun handy.
Commercial systems with premade forms, heating blankets with thermostats etc. are no doubt great, but hugely expensive if you aren't going to make a lot of identical guitars.
 

betocool

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I found that the neck always tends to bow after you string the guitar the first time, it takes a few days. Then, adjust with the truss-rod, re-tune, and play. You may have to re-check a few days later. I would definitively not build a guitar without a truss rod.

My 2p.

Cheers,

Alberto
 

wingcommander

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Second Acoustic and the Florentine Cutaway​

I followed the same process for bending the sides for the second acoustic; again soaking the wood in the bathtub and using the same bending iron (thanks @betocool). This time I had to bend two sides and an extra piece for the cutaway as shown in the pic below.

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I glued the end block the same way as I did for the first acoustic. I did get a bit of slippage of the end block during clamping and gluing, so I’ll have to do a bit of extra levelling before the front and back go on.

Before I make the neck block I have to do some cuts of the side for the Florentine cutaway. This is where things could go pear-shaped folks; hang on to your hats.

I first cut the side and the cut-away pieces according to my template. I then filed and sanded mitres on the ends at the appropriate angles. I taped the ends together and held them in place with masking tape and then wicked CA glue into the join. I forgot to take a photo but it looked reasonable to me.

I then made a wedge to glue on the inside for reinforcement. This I filed and sanded as best I could to get a flush joint. It was difficult because the piece was small and one face was convex and the other concave. I glued the reinforcement in place and held it in place with small clamps.

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I made a neck block the same dimensions and of the same wood as used on the first acoustic. After some measurements I determined where the cutaway would join the neck block, and then I cut, filed, and sanded the mating surface on the neck block. I glued the top side to the neck block first as I plan to hide the joint (with the cutaway) by the heel of the neck.

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After the neck block joint had cured I trimmed off the overhang and re-sanded the curve where the cutaway will go. The next picture shows the cutaway glued in position.

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With the overhang of the cutaway piece trimmed off I now have the sides all glued up to the tail and neck blocks. The joints could have been a bit better, but overall not too bad by my standards.

You can see in this photo what I meant about the left side of the neck block could have been a smidge wider so that it could follow the curve of the cutaway a bit more. It should still be more than strong enough I think.

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Here’s acoustic #2 with sides all glued in place in the jig.

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1bad914

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Nice work. I own a cutaway, but rarely play below the 12th fret on it, but building a cutaway is definitely in my future. I prefer the Florentine.
 

Freeman Keller

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Good job, Wing. I have only done one cutaway, a Florentine, and it was for someone else. Like 1bad I don't play above the 12th fret on acoustics and really don't want to risk breaking expensive wood trying to bend something I don't need. Yours looks great.
 

betocool

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I wholeheartedly support the cutaway. Otherwise "Wish You Were Here" is too difficult to play (15th fret at the solo IIRC). And since that is one of the reasons to learn to play, well... for me the the cutaway stays! ;)

Cheers,

Alberto
 

wingcommander

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Making Fretboards​

Surfaced a couple of bits of wood to make fretboards. As I tend to do (because I’m cheap) I used recycled wood, from origins unknown. I started off with grey and weathered boards, and it’s a lucky dip as to what I’ll end up with – but I like that. The two fretboard blanks ended up being two different timbers, two different colours, but I like the look of both of them.

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I levelled the first one down to a smidge over 6mm thick, and then swapped by router traveller to the 12” diameter profile. I then radiused the first fretboard.

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It’s a bit hard to tell but the radiusing is a bit piecewise-linear as I used a flat router bit and made passes lengthwise. It should come out nice and smooth and round once I sand with my 12” radius sanding beam.

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I’ll do the smoothing and fret slot sawing once I have the other fretboard to the same state as this one. Note that the fretboard is wider and longer than it needs to be, so it’ll need trimming down the track.
 

wingcommander

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I like the jigs! Did you glue both ends of the fretboards with hot-glue?

Cheers,

Alberto
In the past I have used screws but they apply pressure on the wood and get in the way, or double-sided tape but that only works when you have one flat, smooth surface to work with.
I found the hot glue gun in my wife's craft cupboard so that I'd give that a go. Works really well - holds very well, doesn't damage the wood, and is easy to remove. Will use it from now on.
 




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