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Bracing fix...
http://www.luthiersforum.com/forum/viewtopic.php?f=10101&t=28563		 Page 1 of 1
Author:  morgdan [ Mon Aug 09, 2010 12:19 pm ]
Post subject:  Bracing fix...
At the risk of exposing my novice status...

Two days ago: I glued up the x-brace on a guitar that I am building.

Yesterday: After a sleepless night of dwelling on my insecurity about the glue job, I decided to remove the braces and re-glue (I won't bore you with the reasons for my insecurity.

Today: I am looking at the top and observing that some of the cedar came up as the bracing was removed leaving voids, the worst of which is under the x-joint.

Now, my two current concerns are: Have I significantly weakened the top (should I start over?), and what can I do to restore a decent gluing surface for the bracing?

I have considered moving the bracing slightly so they are on a clean surface. I have also wondered about filling the void with something like epoxy and leveling before gluing on the bracing.

Any thoughts? idunno
Author:  JohnAbercrombie [ Mon Aug 09, 2010 12:42 pm ]
Post subject:  Re: Bracing fix...
It's always tough to tell from a pic, but it doesn't look too bad/beyond hope to me.

The way I look at it, at the brace location, the top is 10mm thick or more. I'd avoid sanding the whole top down too much, though.

How thick (flexible) is the top? If you are already 'on the cusp of disaster' to quote a noted authority ;) , it might be a problem.

Cheers
John
Author:  morgdan [ Mon Aug 09, 2010 2:17 pm ]
Post subject:  Re: Bracing fix...
Right now the top is at about .095"
Author:  David Malicky [ Mon Aug 09, 2010 2:48 pm ]
Post subject:  Re: Bracing fix...
0.095" is thin, especially for cedar... little room for more sanding. What body size are you building? Also, was the original X-pattern forward shifted or standard placement? (You could swap placements if one or the other.)

It's probably salvageable in some way, but considering the low cost of tops, I'd suggest chalking it up to a learning exercise and starting with a fresh top.
Author:  jfmckenna [ Mon Aug 09, 2010 2:49 pm ]
Post subject:  Re: Bracing fix...
If they are really deep then you can scrape off the fibers with a sharp chisel and glue them back in place. This is common on bridge replacements where the bridge ripped off the top. But it looks ok to me from your pic.
Author:  morgdan [ Mon Aug 09, 2010 3:11 pm ]
Post subject:  Re: Bracing fix...
I'm building a 00-12. I'm not familiar with "forward-shifted," but that's the kind of idea I was looking for. Is there an example of that somewhere?

I thought about gluing the pieces back in place...I might try that too.

What would be the typical thickness of a cedar top on a steel string?

In the meantime, I've also ordered another top just to have...I may end up using it. Most lessons I've learned in life have been much more expensive!
Author:  JohnAbercrombie [ Mon Aug 09, 2010 3:36 pm ]
Post subject:  Re: Bracing fix...
If it were my project, I'd be happier having any 'missing splinters' under the brace, rather than next to it- so I wouldn't move the X-brace.
An otherwise properly glued brace is not going to pop loose because of a few small voids - think about classicals with fan braces passing through 'holes' in the transverse brace, for example.

For me, whether to replace the top would depend to some extent on how much work/money was in the rosette, so something else to consider. I agree that the money is not that much of an issue when talking about top wood.

Cheers
John
Author:  Alain Moisan [ Mon Aug 09, 2010 4:06 pm ]
Post subject:  Re: Bracing fix...
Based on what I see in the pictures, I'd make a new top, regardless of the work/cost in the rosette (which you might be able to salvage, by the way).

My 2 cents...
Author:  Daniel Minard [ Mon Aug 09, 2010 4:29 pm ]
Post subject:  Re: Bracing fix...
For the time & money involved, is it worth it to you to risk a poor joint over the missing fibres?
Also, you can't know how much fibre separation you have adjacent to the visible damage.
If you REALLY want to use that top... You could always (gasp) epoxy the braces down. Or use medium viscosity CA.
Personally speaking, I would toss that top before I sunk a lot more effort into it.
Author:  woody b [ Mon Aug 09, 2010 4:43 pm ]
Post subject:  Re: Bracing fix...
IMHO .095" is too thin for a Red Cedar top on a steel string, even without the missing splinters.
Author:  morgdan [ Mon Aug 09, 2010 5:23 pm ]
Post subject:  Re: Bracing fix...
woody b wrote:
IMHO .095" is too thin for a Red Cedar top on a steel string, even without the missing splinters.



I think, for peace of mind, I'll replace the top. What would you suggest as a thickness for cedar/steel string?
Author:  woody b [ Mon Aug 09, 2010 5:54 pm ]
Post subject:  Re: Bracing fix...
I thickness by deflection. The thinnest Red Cedar top I've used was .115". Alot of my Spruce tops are under .100"
Author:  truckjohn [ Tue Aug 10, 2010 7:48 am ]
Post subject:  Re: Bracing fix...
Next time.....
You may decide it is better to plane or chisel down the X-brace to nothing without cutting into the top itself... sacrificing the X-brace instead of the Top itself....

It's usually an easy call when a stick of Bracewood costs ~$4.00 and a good Cedar top set without rosette starts around $25.00

Thanks

John
Author:  morgdan [ Tue Aug 10, 2010 1:26 pm ]
Post subject:  Re: Bracing fix...
That is really great advice (planing down the braces).

I think the most important thing I learned through all of this is that I had gone to thin with the cedar. For that reason I'm glad I did this...better than replacing the soundboard later!

I had put in an abalone rosette, but I think I'll be able to salvage that.

Thank you all for your help!
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