Official Luthiers Forum!

If you use the gum method of attaching the Back you will get very little glue squeeze out, which is why I can glue the Top on first.

Hello Michael, can you elaborate on "the gum method"?

Thanks!

Rob

You create a Gum, as in Gummed envelopes. Doubt it will work with Titebond but it works with Hide Glue. You just coat the rims with Glue, allowing it to dry. You might need two or three applications. Moisten it, put your Back on and heat through with a clothes iron or you can feed very dilute glue in with a palette knife.

for me it's top first, brace refinement, then back. the top is bound btw because it does make a difference. i've noticed that that cutting the binding channel drops the top pitch a lot. adding the binding brings it back up to just slightly higher then where you started. i can also check neck alignment, hardware fit up, bridge pin placement etc... imo there's just so much more control in doing the top first. my current problem is that i'm doing small guitars and my hands don't fit through the soundhole!

I also haven't built any guitar nor have I held one in my hands, but what you said is obviously the truth, specially for people playing while looking at a mirror inside their guitar (as JF wisely pointed out).

More seriously, I don't give much consideration to glue squeeze-out, as I put just enough glue not to have glue drooling on the sides. Thus I glue both top and back at the same time. That said, I wouldn't advise beginners to do it this way. You sort of have to know what you are doing before you go this route.

_________________
Alain Moisan
Former full time builder of Acoustics, Classicals and Flamencos.
(Now building just for fun!)

I don't use a cork shim, I use a hardboard shim. No compression, so that problem is eliminated, and I can clamp down as hard as I need with no worries.

However, like Trevor said, plopping a mold with sides down onto a dished back is loads faster. Either make a mold for every shape, or make a workboard for every shape. You still have to make something.

The deal for me is the neck angle. I build with a 90 degree neck angle at the neck joint and tipped shoulders to create 1.5 degree neck angle so the neck is straight from the nut to the last fret no falloff. Molds don't really work for that. It probably could, but I'd have to design some kind of shim to press the shoulders back.

I don't have to fit or floss the neck joint as much, and I don't have to flatten the soundboard under the fretboard flat, so that's faster, making up for the 3 or four minutes it takes me to clamp the sides down.

It's not so important WHAT method you use, but HOW you use it, and can you get your desired result.

_________________
Old growth, shmold growth!

Back first for me. I sand the final angle into the upper bout of the rim for the neck set after the back is on.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

Depends.

_________________
.

Audiences and dispensations on Thursdays ~ by appointment only.


.

Rob, i like that idea. I'll likely do the same.

Trevor, Thanks for the reply, much appreciated. I'm enjoying reading everything on your site! I haven't found anything specifically about preparing the sides yet, but at some point I'd be very interested to read your book! I've just got everything for my go-bar deck. I used spool clamps the first time and Cumpiano's method the second, I can't wait to try it this way. I'm not sure about hot hide glue yet but I keep hearing encouraging things about fish glue(?).

the guitarwhisperer, A hardboard shim would've been better. And the sloping shoulders make sense. I'm not really sure if it's within the bounds of this thread but that's one of the things I need to research; how to get the soundboard/neck geometry set correctly when using radius dishes to prepare the sides. Obviously, I've still got some reading to do! I've trawled through some really old threads!

Todd, Thanks for putting everything into context! Some people do make it all seem so simple but I've made enough mistakes to know that I need to understand a process as well as possible before attempting it.


Based on what everyone has said, I think I'll make a mould. That does mean I'll have to do slightly better on the bending iron next time, though. I mean, to most people my last one (my avatar) looks fine but it wouldn't fit absolutely perfectly in a 00 mould. Is that normal? I didn't think I could expect perfection when bending sides by hand with such little experience. I don't want to have to make a bending machine, too!

It's a matter of deciding what you want to do and developing a system around that, and understanding it start to finish.That's just a matter of time and study.

I went and learned a complete system from William Cumpiano in his workshop, which has evolved quite a bit from his book system, which I have since found to be nearly incomprehensible. I've never attempted a build from it, but I read it quite a bit before deciding to learn from him directly. I like the system a lot.

My neck junction is 90 degrees. If you're doming the top, the angle changes by the degree of the dome, and the neck is matched to it. The right dome radius will yield the correct angle.

I'm somewhat intrigued by the guys that sand the angle into the rims and bend the soundboard around that.

_________________
Old growth, shmold growth!

More specifically, you can use a sliding T-bevel to measure the angle and transfer it to your neck.

Robbie has a good video tutorial on using a sliding bevel, somewhere. Can't find it right now.

_________________
Old growth, shmold growth!

The big fly in the ointment with upper bout angle is how much the whole shebang is going to move with string up. If you have your upper bout angle exactly co-planar with your correct neck angle with no tension you are likely to have a rising extension post settling in and that's bad. You can sand drop off into the fretboard to some degree but it's nice not to have to do a lot.

A floating extension solves this but for the rest of us we just have to get a feel for the movement our guitars will produce with tension and perhaps a year post completion and use that to set the upper bout angle. The goal is to have the extension co planar after everything settles in. It has taken me a lot of guitars to get the feel for the correct initial upper bout angle.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

Thanks, mate! I'll look for that video. I managed to get a good angle with the bolt on mortise and tenon, I'm just trying to get my head around the fretboard extension soundboard area with radius dishes. I'll get there! Still a few weeks till I can start.

Great that you learned from him personally. I read his book and then built a guitar on a course. I admire those who did it on their own first time from Cumpiano's book. In a way I wish I had just bought the wood and tried on my own but it was very useful having someone with experience watching over me, and it prepared me pretty well. As you say, now I'm just trying to develop a method that works well for me.

So am I!


Nice one Terence, The floating fretboard appeals to me for that very reason. My next build is actually likely to have an electric style neck pocket so I'm more worried about routing the pocket base to the correct angle, I guess. That will be much like a floating fretboard so I suppose the soundboard isn't going to present much of a problem this time.

I got Trevor's books too.

If I were to go the floating fretboard extension, there's some techniques I'd adapt from them.

I went solo and taught myself how to build electrics by myself completely from scratch, no books, from reverse engineering strat and tele necks and bodies I got from Warmoth and talking to local woodworking shops for tips on equipment and technique.

The only book I'd read up to that point was Erlewine's setup and maintenance book. The internet was developing, all I had was my AOL account and had no clue that there was a web beyond that, if it wasn't on AOL, I didn't know about it.

The guitars turned out very well, but I definitely wasn't what you'd call a "natural" at it.

So the Cumpiano tutorial was very handy.

_________________
Old growth, shmold growth!

Terrence,

Just so I can understand the terminology and technique - with your method would it be ideal to have the neck angle slightly steeper or whatever it takes to create a slight lift or gap at the end of the fret board before gluing it down, thus creating a slight bow or convex curve in the fretboard over the upper bout that will be alleviated/straightened in the future with string tension/neck movement?

To put it another way, I can see a very similar situation where a shim might be deployed to 'level' the fretboard before gluing if the space under the fretboard extension is too high. Are you saying there's a theoretical 'ideal' gap that should simply be glued down and await any future tensioning movement to level completely?

_________________
Thank You and Best To All

That's about it Larry. I try to create a neck angle that will be appropriate for my anticipated bridge/string height after the guitar is under tension. The angle of the upper bout is a little less than that angle so that the fretboard will wind up more or less co planar after string up.

I use a double tenon neck attachment and for me I need around 1/16 clearance over the bridge on an unstrung guitar to get it right under tension. If the upper bout matched that angle unstrung there would be a big extension rise strung up.

This is just my stuff, everyone's guitars are unique and require different approaches. I'm always changing too, especially after reading various posts here.

_________________
It's not what you don't know that hurts you, it's what you do know that's wrong.

We've drifted a little from the OP's question, but as getting the neck angle right is critical to good assembly process, I thought I'd add this in, prompted by Terrence's comments.

Most people do the action/string height above the top calc. using straight line trigonometry. However, most guitars run with at least a bit of neck relief, so the action comes out higher than the straight line calcs predict (unless arrangements are made) and then the saddle is dropped a bit to compensate. What this does is rotate the string plane relative to the fretboard curvature, resulting in a "ski jump" effect at the sound hole end of the fretboard. So, as Terrence was pointing out, you need to add in an allowance for this if you want really good action over the higher frets. It doesn't prevent the top of the neck being coplanar with the upper bout, it just means that the UTB has to be curved appropriately, with allowance for the effect of neck relief.

_________________
Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au