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3 piece backs - jointing and gluing question
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Author:  John A [ Tue Jan 26, 2010 2:27 pm ]
Post subject:  3 piece backs - jointing and gluing question
Hi everyone,

I am working on jointing my 3 piece back. It is maple, with a slight hint of birdseye, not a ton of birdseye.
I am working with 3, 5 1/2" pieces and I need to joint them for the back. Should I joint all three pieces at one time ? all together ? Or just do two at a time ?
I was thinking of jointing two pieces and then gluing, then coming back and then jointing my glued two pieces to the single piece and then gluing that one in. Or should I glue all three pieces at once ?
Still having a little trouble jointing, so I am hoping I don't plane away too much wood - I am making a classical, my first guitar.


Thanks!
John
Author:  wbergman [ Tue Jan 26, 2010 2:37 pm ]
Post subject:  Re: 3 piece backs - jointing and gluing question
This depends upon your clamping method and skill. There is nothing wrong with doing all three at once, if you are skilled enough. Because you are new, I suggest that you glue one joint at a time and let the first dry before doing the second.
Author:  Alexandru Marian [ Tue Jan 26, 2010 2:41 pm ]
Post subject:  Re: 3 piece backs - jointing and gluing question
What wbergman said.

I should add that if your center piece is wedge shaped, you can easily use this in your advantage. Joint the pieces, arrange them tight on a bench, clamp real tight the outer pieces to the table. Pull out the center piece, add the glue, push it back in. Hit the bottom a couple times with a mallet and voila.
Author:  John A [ Tue Jan 26, 2010 2:56 pm ]
Post subject:  Re: 3 piece backs - jointing and gluing question
Great idea about the wedge...but I think my pieces may be a little narrow to use the wedge design, and if I did, I am sure the wedge would be lopsided.
Author:  JohnAbercrombie [ Tue Jan 26, 2010 2:57 pm ]
Post subject:  Re: 3 piece backs - jointing and gluing question
Good advice already.
I've done all 3 at once, the few times I've done it.
If you do the 2+1 method, you'll probably have to re-joint, as most clamping methods 'mess up' the outer edges of the plates to some extent. (The 'stretch tape' methods avoids edge damage, I think.)

Cheers
John
Author:  truckjohn [ Tue Jan 26, 2010 3:47 pm ]
Post subject:  Re: 3 piece backs - jointing and gluing question
I have done it both ways and personally have much better success at only gluing up 1 joint at a time.

This takes a whole lot of time on a multi-pc top or back. I am currently building a Size 5 tenor guitar (Or maybe a Parlor guitar.. Haven't decided whether it will be 4 or 6 strings) out of Pallet wood (for the $100.00 MIMF Acoustic Challenge)... I am jointing up a 6-pc back and a 4-pc top for a 12" wide Guitar.... Doing it one piece at a time ends up taking me 5 days for the back and 3 days for the top... but the alignment comes out much better for me.

When I did my "Jointing Practice" tops made out of resawed 2x4's.... (a 13 and 16 piece top respectively) -- I tried to do them 3 or 4 at a time and I ended up redoing a bunch of the joints because a piece may shift up or down during clamp up.

Thanks

John
Author:  mateo4x4 [ Fri Jan 29, 2010 11:56 am ]
Post subject:  Re: 3 piece backs - jointing and gluing question
I regularly do 3 or 4 part backs and tops, as I don't have room for a height increase on my bandsaw and max out around 6". The only issue I have had with gluing all at once (using tape method) is getting everything to lay totally flat while it dries. I recently just started making the plates a bit thicker and spending some quality time with the thickness sander to fix problems, but this may be 'fix it with a sledgehammer' method, when a different approach may work better. laughing6-hehe

I'll have to give the one at a time method a shot (arg...patience was always an issue for me!) and see if it goes better. Oh...love the idea for the wedge too!

-Matthew
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