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L-OO Top bracing/ body twist issue
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Author:  Bailey [ Sun Nov 21, 2010 3:54 pm ]
Post subject:  L-OO Top bracing/ body twist issue
I've got 2 L-OO C. Grelier plan guitars ready for gluing tops. I have 1 question and 1 issue.

Question: The top bracing are shown as standard tapered with basic sloped ends. I see similar bracing patterns on many Luthier posts that show braces scalloped. Would It be a reasonable assumption that these L-OO braces can also be scalloped and still keep their strength. The tops are sitka and fairly stiff.

Issue: I only have 1 form and building 2 guitars....SO...when I removed #1 body with sides (without top) from the form to glue up the back/sides on #2...I noticed the #1 body/sides has a 1/8 to316 twist. In other words...when it's in the form...the top edge of the sides are flat...when it is removed...it has a twist and the top edge of the sides are not flat.
Once I put the back and sides back in the form to glue on the top and the back and sides are again flat for receiving the glued top...will this slight twist stress the top back into a twist once it is removed?????or will gluing the top be enough to make it stable. It seems one of the sides wants to pull outward(towards the top) at the waist when I remove it from the mold causing the body to twist a bit. I assume that once the waist side is pulled back into proper position when in the form and the top is glued holding the waist side from pushing outward, it should be stable. Am I correct???? Or....do I want to attach some kind of interior bracing from side to side or "A" frame support midway up the sides from waist to front or back to help stabilize the twist.
If I lay the guitar body on it's top...it takes very little downward pressure on the back of the guitar to push it flat. If I push the one waist side gently inward the twist goes away.

Kent
Author:  theguitarwhisperer [ Sun Nov 21, 2010 4:00 pm ]
Post subject:  Re: L-OO Top bracing/ body twist issue
You can strut the sides, that'll help. You might want to get a hot pipe and touch up the bend where the twist is occurring, too. I really think that amount of twist won't be a problem, but I like my wood pieces to be as close as possible to the correct final shape before gluing. Of course, that's not always possible, but most of the time it is.
Author:  meddlingfool [ Sun Nov 21, 2010 4:51 pm ]
Post subject:  Re: L-OO Top bracing/ body twist issue
I think you'll be fine as is without any extra mods at all. Everything locks into place after glue up. Could you imagine how much effort you'd need to exert in order to intentionally twist a closed box?
Author:  Tom West [ Sun Nov 21, 2010 5:39 pm ]
Post subject:  Re: L-OO Top bracing/ body twist issue
Kent: It seems only one set of sides have this problem...??? I would think it is important to discover why. Mold not square to the top, blocks not glued on correctly,sides not matching the mold , etc...??? Discover why and you have the solution for the future.Not trying to rain on your parade but if you don't know why it could happen again in the future.Good luck.
Tom
Author:  Bailey [ Sun Nov 21, 2010 5:56 pm ]
Post subject:  Re: L-OO Top bracing/ body twist issue
The form is square and my other back and sides (Curly Koa are fine).
I did have a little trouble bending the sides on this set of Cocobolo. I needed the forms inside spread braces to get them tight against the form sides above and below at the waist curve. I just figured once I got the back on...it would stay in place. I definitely will at least put my waist spreader in the form when I glue my top. It is small enough to get out the soundhole.

Thanks all.

I'll be gluing up tonight.


Kent
Author:  Hupaand [ Sun Nov 21, 2010 7:06 pm ]
Post subject:  Re: L-OO Top bracing/ body twist issue
You mean some people get them better than that?
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