Official Luthiers Forum!

Hey all,

So I picked up some Honduran Mahogany today in 7 inch wide boards. I plan to centre join the wood and make a few solid body blanks for future builds topped with figured Maple.

Question - When you are joining wood for guitar building do you use dowel plugs or biscuit joints?

Sorry for the embarrassingly stupid question, but I would rather get started in the right direction.

Rick

I dont use dowels or biscuit joints. I just flatten the sides of both boards, put some glue on there, and glue them together between some bar clamps. Never had a problem doing it that way.

Biscuits can help strengthen a weak join and dowels can help in aligning difficult to align pieces for gluing. Neither should be necessary for the type of joint you are making.

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Old growth, shmold growth!

No reason to reinforce a body joint like that. Get the surfaces straight and clean, apply Titebond regular or extend to both edges, and use adequate clamping pressure. Leave it sit overnight in the clamps at indoor temperature. I routinely glue sapele body blanks this way.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Leave the biscuits and dowels to the cabinet makers....

Reminds me of the pinheads who used to come in my shop and say, "Oh, you're a wood worker. Can you make me a shelf?". We're not carpenters.... we're luthiers.

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"Act your age, not your shoe size" - Prince

My Sister recently ended a conversation with me with the following phrase...

"If you can build a Guitar, surely you can re-build a DECK!"....

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Jim Hansen

Okay, all jokes aside, let's don't confuse our first time correspondent.

No dowels or biscuits are needed nor desired. A straight, perfect joining edge on each joining piece is desired. Hold the two surfaces together and then hold them up to a strong light. If you can see light through them, they aren't ready for gluing yet. This is so frustrating to most of us. I still struggle with it every single time. It makes me crazy, but I press on until the joint is light-tight.

Google up the term "shooting board". You will soon see how a shooting board works with a plane. If all else fails, you can glue sandpaper to a 36" carpenter's level and use that after the plane. I admit I do that most of the time. If you do sand, then you must meticulously get all the sanding dust off the joining surfaces before you glue. I am talking about sweeping with a brush and then wiping with a paper towel soaked in naphtha. You'll be amazed how much sanding dust you see on that last paper towel.

When your towel comes away clean and your joint is finally light-tight, it's ready for glue. Be patient, and you can do it.

Thanks everyone,

Very helpful.

Rick

I always build one piece bodies...

However when I fall on a very rare piece of wood which is too small for building a one piece, I use a shark joint...
(but there is no need too do this, a simple joint is perfect)

(watch the end grain)

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http://hufschmidguitars.com

I give.
What's a "shark joint"?

I dont know how you guys call it...

Taylor Guitars has been using it for many many many years for their headstock joint, nothing new at all

Do you call it a Finger joint by any chance?

whatever

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http://hufschmidguitars.com

I would call that a fingerjoint,
but it's slightly different.
The v's are symmetrical.
I like the sound of a shark joint better!
Do you have a cutter that does that?
Oh, nice git by the way!

I dont, my workshop is too small for big power tools so I have to go and see a carpenter friend of mine to use his tools...

Its a simple set up on the jointer, you can order a blade which is configured to cut that way as oposed of cutting a flat surface, nothing new...

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http://hufschmidguitars.com

That "shark" joint has a purpose on that Taylor neck/headstock transitional area where stress accumulates. A finger joint like that adds many times the surface area to that joint, which spreads out the load, reducing any focused point load on the glue, making it work a fraction as hard as it would in a simpler joint.

Joined body panels have no stress to speak of. Without stress the only consideration is the aesthetic aspect of the joint. Joined edges are as beautiful as your craftmanship dictates. Make the edges flat, clamp them up well......viola.....a beautiful joint that will never fail unless you clamped stressed parts together. So don't do that. Don't forced them flat and glue them....work each piece flat THEN glue them.

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I read Emerson on the can. A foolish consistency is the hobgoblin of little minds...true...but a consistent reading of Emerson has its uses nevertheless.

StuMusic

Speaking of shelves and finger joints (isn't that what this thread was about? ) I bought some scrap oak shelves in the cheapo bin to make guitar hangers from and they were finger jointed with what looked like a random pattern rather than the even ones you usually see. Worked too, very tough to notice unless you really look hard.

On topic, I don't own a biscuit jointer but I can see where one might come in handy for glue ups on solid bodies. Not for strength or to take the place of good jointery, but for alignment.

I like Patrick's method actually, might have to look into that since I almost always do 2-piece bodies.