Instructables
Picture of Neck for a Stringed Instrument
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This is a technique I have used for longer necks. I'm demonstrating it on a uke neck because they seem less sacrosanct than guitars or violins. As such, people are ready to tackle a uke, patching together cigar boxes and plumbing parts with a vigor and profanity rarely administered to the noble guitar. Thhpt.
Basically, 1/16" thick slabs of wood are bent 14 degrees to make the head/neck transition. Then fiberglass is embedded in a rigid glue between the wood laminates. I use the urethane-glue-known-as-Gorilla because of its rigidity and availability. An epoxy would also do well here, but not necessarily better; it can be hard to find an epoxy of the appropriate viscosity, but Gorilla glue can be found anywhere.

This method eliminates the deadly grain run-out on the head/neck transition, which is the first spot a stringed instrument will snap when dropped or mishandled.
The fiberglass will handle most of the stress of the strings; this allows use of a lighter wood, creating a lightweight but extremely rigid neck, less fatiguing to hold, less susceptible to climate changes and ready for a lifetime of music.
 
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Step 1: Description

A steel sting instrument is under more tension, so for those necks I bend the laminates (or "lams") and fiberglass to form the heel. Most woods do not easily bend that sharply, even in thin strips, so we'll avoid that chore for this relatively low-tension neck and build up the heel like a classical guitar.
rimar20002 years ago
Very interesting, thanks for sharing.

Your English is too rich for me, please translate Thhpt, I couldn't find the meaning.
asdterror (author)  rimar20002 years ago
My apologies. It's spelled "Thppft".
Sorry for the confusion.
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Thanks, but for Thppft I neither found the meaning in Google.
asdterror (author)  rimar20002 years ago
It's functionally like a sigh; not really a word. Something for when words fail you. "Thppft" is the sound of "blowing a raspberry", where you stick you tongue out and blow. This has the double function of making an inarticulate, derisive sound, and of letting you flap your tongue at the thing that is frustrating you.
In this instance, I was expressing frustration that most people don't approach guitars (building or playing; or for that matter drawing, or cooking, or love, or conversation) with the same zeal as a child with a kazoo.
OK, thanks.
friger2 years ago
I am facinated with your laminating method. Having done many laminate pieces, I've never used fiberglass cloth as an intermediate layer, nor have I used gorilla glue with the cloth, it has always been epoxy or polyester resin for me when glassing. My question is, do you think the cloth is a necessay step and why?
asdterror (author)  friger2 years ago
Fiberglass is extremely rigid even in compression when encased in glue ( wiki ). If you used a stronger wood like maple or even mahogany the 'glass wouldn't be strictly necessary, especially on a uke, with its short scale and nylon strings (meaning that it needs little tension to create a high pitch).

But I figure: it's already apart, and the glass should add quite a bit of strength and rigidity, and allow for a lighter neck. I think a light, rigid neck has better sustain and bandwidth.
The skeptic in me groans at this. I do need to run more tests. That's another appealing aspect of ukes-- they are structurally miniature guitars, and the steps to build them really are the same, just scaled down. So I can build a series of necks with different specs and techniques and (hopefully) work out what is useful/resilient/consistent and how the specs and techniques affect the sound of the instrument while expending less time/resources. While a uke doesn't NEED as strong of a neck as a steel string baritone guitar, it is nice to know that you could bludgeon a velociraptor to death with it and still play sum tUnE-YarDs.

Of course my Google-fu is failing me now, I can't cite the following but I'll see if I can find something concise later (Groan-- Skeptic-In-Me): Gorilla Glue is a polyurethane, and is actually closely related to resins, in that moisture acts as a catalyst. It does not set by evaporation.
Epoxy would be stronger, but not by enough to justify the difficulty and expense. In large quantities (the gallon jugs one could get at boat building shops) it would be a good way to go, and while I aspire to one day go through gallons of glue in a year (I am now recalling a stair-building company I worked for, with 55 gallon drums of Titebond on tap. Sigh.), I am not there yet. 

The uke neck used about 3 ounces of Gorilla Glue. So. Gorilla Glue is just that more useful and convenient that I'd rather have a bottle of that laying around.

I have made a 31" scale baritone guitar using poplar, without a trussrod, using this method, and even tuned it up to standard tuning before I learnt better (and broke a few strings). It deflected from perfectly flat to slight relief. No velociraptor has menaced me as of yet, so that final test is untried. But I live in hope. What is your experience with lams/epoxy? I am pretty new to the technique. I may be repeating old mistakes.
I've done things like vaccuum forming large boats using epoxy as the bonding agent to great sucess. I've done many smaller things too, from guitar stands and curve legged tables to fishing nets. I hate straight lines and laminating is far more controlable than steaming. You are spot on when it comes to the strength,, while there seems to be fewer and fewer velociraptors around these days to test the strength to weight aspects of the method I'm sure a panda would be a suitable test bed. On the down side of epoxy, the cheaper qualities are prone to failure after a few years and the seam lines tend to be more visable. PVA glue is a very suitable glue but I don't think it would work as well as gorilla glue when using your glass cloth method which I am going to try very soon.
asdterror (author)  friger2 years ago
One thing I didn't explicitly say regarding polyurethane glues: like epoxies and hot hide glue they are extremely rigid. PVAs can be a little mushy, and that could absorb vibration, much like Green Glue (an acoustic isolation compound).
It can also allow for creep in the joint. A little movement along the length of a lam can translate to a large movement on axis. On a guitar neck, where reflex is measured quite intimately and minutely, a little creep would be ruinous.

Reminds me again of stairbuilding. The rhythm of climbing stairs is also measured intimately and minutely. If you find yourself tripping over the same step repeatably: measure it and the surrounding stairs. The offending stair might be proud a mere 3/16". An embarrassingly small amount to trip over, but over you go.

Maybe it's not a big deal, using urethane instead of hot hide or epoxy or PVA. I don't know yet. We'll work on it.  Please let me know how it works for you.

Big boats! Sounds like fun! I hold a secret desire to build a big sailboat and just bum across the seas. It's still secret! Thank you, anonymity of teh internets! Also, pandas seem like small mountains. I lack the faith to try walloping one.
friger2 years ago
The pictures of the Gibsons with the broken necks made me weep a little.