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X brace dilemma
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=17763		 Page 1 of 1
Author:  Jeremy Douglas [ Fri Jun 27, 2008 12:31 am ]
Post subject:  X brace dilemma
It looks like I didn't do a very good job of making the center notch for the X brace because a few minutes after gluing it up I noticed a hair line gap on one side of the brace (the overlapping brace). It's clearly due to the X not being notched properly since it is worse there and there's no gap toward the ends. I don't know how I missed that in the dry run but I did, it's glued on now.
The gap appears to be less than 1/64". If the glue fills the gap am I ok? I'm worried that if I tried to remove the braces I'd tear the soundboard up. If I had the materials and tools I'd just redo it but this is my first guitar (kit) and I don't have a jointer or drum sander so I'd have to pay big bucks to get a new 'serviced' top from LMI. So what should I do idunno

btw, I'm using fish glue if it matters.
Author:  Steve Saville [ Fri Jun 27, 2008 12:43 am ]
Post subject:  Re: X brace dilemma
Can you show a picture? I'm having trouble understanding exactly where the gap is.
I wouldn't fill a gap with glue. I might try to fill it with wood shavings and glue, but I'd like to see it first.
Author:  Frei [ Fri Jun 27, 2008 12:54 am ]
Post subject:  Re: X brace dilemma
You could cap it with a martin style cloth patch, that would cover it. You could also use a plane shaving to fill it in if you wish.
Author:  JJ Donohue [ Fri Jun 27, 2008 1:52 am ]
Post subject:  Re: X brace dilemma
If necessary, you could easily plane off the braces and start anew. I did just that on my 1st and it was a great learning experience in many ways.
Author:  Arnt Rian [ Fri Jun 27, 2008 6:02 am ]
Post subject:  Re: X brace dilemma
If I’m reading this right the x brace notches were not cut deep enough and the brace with the ‘down’ notch is not glued to soundboard next to the x intersection. If so, redo it! Take whatever time and effort you must to make this right, it is that important. I would chisel them off and make new ones, it shouldn’t take long.
Author:  Jeremy Douglas [ Fri Jun 27, 2008 9:31 am ]
Post subject:  Re: X brace dilemma
Arnt, you're close but it looks like it wasn't made deep enough on the soundhole side, the other side glued down fine.

Here's a couple pictures of the gap:

The gap is along the bottom of the brace that's shown horizontally in the picture.
Image

Another angle.
Image
Author:  Barry Daniels [ Fri Jun 27, 2008 9:55 am ]
Post subject:  Re: X brace dilemma
That gap is unacceptable. Those braces will delaminate over time if you leave it like that. Plane them off and make new ones.
Author:  bluescreek [ Fri Jun 27, 2008 9:58 am ]
Post subject:  Re: X brace dilemma
you need to replace those braces
Author:  Jeremy Douglas [ Fri Jun 27, 2008 10:08 am ]
Post subject:  Re: X brace dilemma
Bummer, looks like I got some planing to do.

Thanks for your help everyone [:Y:]
Author:  jhowell [ Fri Jun 27, 2008 10:15 am ]
Post subject:  Re: X brace dilemma
Jeremy--

If we had a show of hands for who all here has done this, you'd be seeing waving all over the world! laughing6-hehe

They'll come off in a hurry and they are easy to replace. If you don't have bracing stock on hand, you can get some spruce from a local R/C airplane hobby store. Its good quality, but a little spendy for regular use.
Author:  Pat Foster [ Fri Jun 27, 2008 11:15 am ]
Post subject:  Re: X brace dilemma
Jeremy,

Not a big deal, really. Happens to just about everybody.

I'd use a chisel. If you have little to no runout in your brace stock, you can split the brace from the end for a good part of its length, but don't try to take off too much or you might split your top. Take small bites, like 3 or 4 splits, and when you get close to the top, carve slow and get it clean and flat. It will be fine.


Pat
Author:  Howard Klepper [ Fri Jun 27, 2008 11:28 am ]
Post subject:  Re: X brace dilemma
Yep, that brace has to go.

I join the X off the top, and allow myself a little extra brace height so that the depth of the notch does not need to be perfect. It's hard enough to get the rest of the joint tight. After I glue, whether the notch was a bit too shallow or a bit too deep, I can trim it to a perfectly flush joint on the surface that glues to the top.
Author:  Eric Mathre [ Fri Jun 27, 2008 11:41 am ]
Post subject:  Re: X brace dilemma
Jeremy,

I find that finish sanding in the radius dish after gluing up the X-brace
will prevent this.

And if you have a Woodcraft store nearby, they carry a product called
"De-glue Goo", which (even though it makes your hands smell like
darkroom chemicals) will allow you scrape off the last teeny layer of the
glued-on braces without scraping into the soundboard.

Apply, wait about 10-20 minutes, and then use a chisel vertically like a scraper
and that almost transparent final layer of bracing wood fiber, along with any glue
residue, will scrape right off. You'll have a pristine soundboard to glue the next
X-brace onto, without gouges, or encrusted glue or leftover fibers.

I also do this when cleaning out the channels in the back joint reinforcement prior
to gluing on the back braces.

Eric
Author:  Frei [ Fri Jun 27, 2008 4:56 pm ]
Post subject:  Re: X brace dilemma
Its good learning experience. I just took the braces off my first top, and the X braces and tone bars were good, but one or 2 finger braces were not so tight in parts and just boinked off with a little pressure oops_sign . Now I know.

I check the brace/board fit with a super thin thickness gauge to check for any high spots.
Author:  James W B [ Fri Jun 27, 2008 6:32 pm ]
Post subject:  Re: X brace dilemma
Hi Jeremy ,Where are you at in Tennessee?I`m in Nashville.Like others have said,those x braces need to be tight on the soundboard.
James W B
Author:  Hesh [ Fri Jun 27, 2008 6:42 pm ]
Post subject:  Re: X brace dilemma
Yeah that won't hold up over time and this is a critical joint.

I too, after gluing the X-brace sand the bottom of it in the dish until marks that I make with a pencil on all legs and at the intersection are sanded off.

Something that helps me to get the fit of the notch nice and tight is to make the notch slightly to small. I trial fit and if I can't press the upper brace into the lower brace I hit it (on it's side) with a plane and trial fit again. After a few iterations of this trial fitting, planing with one pass, the fit gets nice and snug but not to tight. Then the entire thing, once glued is sanded in the dish as mentioned.

I have been toying with the idea of doing exactly as I described above but not gluing the X-brace intersection. Instead, once I have a great fit I would glue one X brace at a time to the guitar top. Once the first one is on clean up is as easy as cleaning up around one brace. Then when I glue on the second (upper) X-brace I also butter up the notched joint. I know that a few of you do this and I see another advantage being that five alignment points that need to be set at once with HHG when gluing a pre-glued X-brace would be reduced to three alignment points.
Author:  Arnt Rian [ Fri Jun 27, 2008 6:46 pm ]
Post subject:  Re: X brace dilemma
emathre wrote:
And if you have a Woodcraft store nearby, they carry a product called
"De-glue Goo", which (even though it makes your hands smell like
darkroom chemicals) will allow you scrape off the last teeny layer of the
glued-on braces without scraping into the soundboard.


Eric, he is using fish glue. A little water should get the remaining glue off.
Author:  Jeremy Douglas [ Fri Jun 27, 2008 9:05 pm ]
Post subject:  Re: X brace dilemma
Thanks again. The idea of touching up in a radius dish had crossed my mind unfortunatley I don't have one. I used a 30' radiused sanding stick made by finding the radius by bending a spline to a certain deflection. I don't know if it would be a good idea to try and true things up with that, it might have the opposite effect.

I should have enough spruce billet left for X braces. I'm just worried about tearing up the top trying to chies the braces off. About the only chiseling I've done is on the back I just finished, which I think turned out pretty well.


James W B wrote:
Hi Jeremy ,Where are you at in Tennessee?I`m in Nashville. James W B


I live in Columbia just down 65.
Author:  Jeremy Douglas [ Fri Jun 27, 2008 11:48 pm ]
Post subject:  Re: X brace dilemma
Well that didn't work at all. it pulled the chisel right into the top. I guess I'll order another one.
Author:  Howard Klepper [ Sat Jun 28, 2008 1:20 am ]
Post subject:  Re: X brace dilemma
A spline curve is not a single radius curve such as most builders are using. You need to review your system for arching or doming the top and the braces so they are consistent.
Author:  Frei [ Sat Jun 28, 2008 1:30 am ]
Post subject:  Re: X brace dilemma
I know that a few of you do this and I see another advantage being that five alignment points that need to be set at once with HHG when gluing a pre-glued X-brace would be reduced to three alignment points.[/quote]

Hesh, you need to eliminate the alignment points. Position the brace, then put a scrap of wood on 4 sides, top bottom, so its tight, then you just squeeze out the glue, pop in the brace, no aligning etc, as its already done. :mrgreen:
Author:  Frei [ Sat Jun 28, 2008 1:33 am ]
Post subject:  Re: X brace dilemma
Get a dish, the radius changes constantly. Its not like a bridge-road, it curves left on top/right on the bottom. Or do it flat top. It wont matter on your first, less problems with fretboard, neck angle.

Sorry bout the top, LMO has student grade Sitka for $15- and they are pretty nice.
Author:  Howard Klepper [ Sat Jun 28, 2008 12:10 pm ]
Post subject:  Re: X brace dilemma
Frei wrote:
Get a dish, the radius changes constantly. Its not like a bridge-road, it curves left on top/right on the bottom. Or do it flat top. It wont matter on your first, less problems with fretboard, neck angle.


The radius in every commercially available dish I have seen or heard of is the same everywhere in the dish. They are sections of a sphere.
Author:  James W B [ Sun Jun 29, 2008 6:45 pm ]
Post subject:  Re: X brace dilemma
Hi Jeremy ,sorry your having problems.Pm me we`ll get together sometime,and talk shop.
James W B
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