Official Luthiers Forum!

Almost have the rim completed so the next step is going to the top and back. Which should I do first? Does it matter?

_________________
Hutch

Get the heck off the couch and go build a guitar!!!!

Back first allows you to easily clean up glue squeeze out that would otherwise show through the sound hole. On early builds we often haven't fine tuned the glue application/volume, and this make cleanup easy. This is how I started.

Top first allows you to more easily fine tune your braces, adjusting voicing after the top is connected to the rim. You can tap/shave/sand without having to reach through the sound hole. This is how I now approach it.

Building guitars is a fine balance of acoustics and aesthetics, and both stunning instruments and total dogs have been built both ways.

Edit: I thought you were ready to close the box. Which to build first—tops are more fun, but require greater attention. If this is your first build, get the back done so you get just that little more experience radiusing, shaping and glueing braces.

I normally do the rosette first and this kinda sets the mood for the rest of the guitar.
Shouldn’t matter matter what comes first though.

B

_________________
My memory is so good, sometimes I remember things that never happened.

This seems to be one of those builders preference type things. It might have a lot to do with how you originally learn too.For example most of the classic books going as far back as Sloan and then Cumpiano all build off the top. My first several guitars were classical guitars built off the top on a work board (solera) so that's jut the way I do it.

I know the usual arguments for both but, I don't think you can really get a definitive tap test done with the top on first to determine if the braces need adjusting and you can easily learn to use the right among of glue when gluing on the back so you don't get any drips. The only other argument I would add for building off the top is that you wont introduce any stress to the top iv you have to squeeze the sides into a mold after mounting the back first. But even that is a stretch.

So I'd just say, think about it real good and make a decision and stick to it.

I do them concurrently since they both have basically the same steps - thickness the plates, shoot the seam and glue up, install the rosette, put them in the go bar and brace them, take the go bar apart and put it away. In fact I might have one plate in the deck while I'm shaving braces on the other, and building a neck at the same time.

I've always glued the top to the rim first, one reason is that because I mostly use bolt on necks I can take the rim out of the mold, slip the neck in place and mark the location of the inserts in the heel.

back first for clean up but it really doesn't matter

_________________
John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

If this is your first time, do the back first. Since the back is usually reinforced, you can get a little practice on getting joint fit correct where it is a little less critical than the top plate.

_________________
Tony Thatcher
Bozeman, Montana

Thank you all. I think I'll go with the back first for the best clean up and practice for the right amount of glue. Plus, I have a radius dish for the back. I'm trying to decide on a simple DIY backstrap and complimentary wedge for my rosewood back and sides.

_________________
Hutch

Get the heck off the couch and go build a guitar!!!!

I do the back first. Partly for cleanup but after I have a relatively stable "boat" I sand the final angle into the rim of upper bout for optimal neck fit. I feel there is less chance the angle of the headblock can change with the back glued on.

I use a Fox adjustable mold but with a conventional mold and if you actually attach the headblock to the mold via screws (as many do) you would have plenty of stability and it would not be an issue.

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

Back first for many reasons .

I like to glue the back on first for the same glue clean up reasons stated above. But it sounds like you might be asking which plate to make first. I like to joint the plates before I do anything else and set them aside. I want the center seam to have plenty of time to give back the moisture from the glue up before I thickness. When I was starting out, I thicknesses too soon and the area around the joint shrunk back. You don't need a ton of time, but I find it easy to just do that first (including the rosette if you are using water base glue for that) then make the rim.

Since you are starting out, I would joint them both then thickness then both starting with the back to get the feel for it. Then brace and shape the back fist for the same reason. You'll also have to do some trial and error and practice to get the plates fitted properly to the rim and clamped in alignment. Since you are gluing the back on first for glue clean up, it will give you a chance to refine that process too.

I like to make a bridge gluing caul when I am done with the top so I can make sure it is a good fit to the bridge plate and braces. It is easier to do it before the box is closed.

As you make more and more, you will start to decide what order works for you. Now is the time to make mental notes of issues that pop up and if a change in process could have avoided them.

_________________
Bryan Bear PMoMC

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

If we are speaking of joining plates, I have several in my shop that have been glued up for a long time now. It's nice to just grab one off the shelf and get right to work. So yeah I too will join and glue plates up first and let them sit till they are ready to use.

I'll get started joining them. Thank you.
I'm still undecided on the backstrip. Is it better to build it in or router it in?

_________________
Hutch

Get the heck off the couch and go build a guitar!!!!

Not to disagree with any of the suggestions, but here's another point of view.

I glue the top to the sides before gluing on the back. Two reasons:

1) If I'm building with a "dead" upper bout, the open back lets me install braces between the headblock and the UTB more easily, and

2) I adjust the X-brace stiffness to give 2 degrees of bridge rotation (ala Trevor Gore) when loaded with string tension. I can do this with the back off by drilling holes for the bridge pins in the top and, temporarily, bolting the bridge in place using long bolts through the pin holes and a through a fixture that can hang a weight. Then I clamp the mold, holding the sides with the top and fixture installed, vertically in a vise, headblock down. Hanging weights on the fixture generates a torque (160 lbs. x ½") equivalent to the strings. Then, by measuring the angle change between the fixture and the mold, I can evaluate the stiffness of the braced top and adjust as needed. I've done this with the back on -- it's much easier with the back off.

Again, imho, it's builder preference. I have argued in the past that routing it in is better because you are creating a lap joint that might hold the back together better in the long run. I still like to think this is true but many many luthiers, including myself, have simply joined a backstrip in with the rest of it. You are going to put a back center reinforcing strip on it anyway to 'lap' it. If it's a decorative tile like one then definitely rout it in because that has no structural integrity.

Top first of course. You can't accurately tap tune without the top being attached to the rims.

Actually you can. I do a lot of my voicing after the box is closed by thinning the edges of the lower bout and listening to the tap tone.

I had a kid who had just finished the Red Wing MN building and repair course spend a summer in my shop. Dana B had taught a voicing course at Red Wing and I learned the technique from him and articles Dana published.

It has become a significant part of my voicing process and has helped a lot in dialing in the sound I am looking for.

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

The easiest way that I have found to get just the right amount of glue is to use a dry or damp sponge (if using Titebond) which is something I saw Mike Greenfield doing. Doing this has really made a huge difference to the point where I feel comfortable putting either on first because the squeeze out is very, very minimal. I do the same with a small sponge for bindings and purflings, which also really helps if you are trying to work clean.

fs1978

Do you put the glue on the sponge or on the lining? Are you using the sponge to regulate the amount of glue, or just to even it out? Are you still relying on applying the right amount?