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X-Brace Intersection
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Post
Phlytyer (Keith)

Total Topics: 37
Total Posts: 273
My turn for a DAQ (dumb a$$ question).

I have seen some who have put a patch of cloth over the X-brace intersection. Is this a necessary step? Should I find some fine linen or somesuch and 'patch' the X-brace intersection? What is the supposed reasoning behind doing so?

My braces came simi-scalloped and the X-brace intersection (d...., I know there is a proper term for this but it escapes me now) was already done. (Note: I had to shim the joint to remove any dead space).

That is where I am at currently. All braces are in place, notches cut for the back side in the kerfing, top side kerfing notches within the hour. And likely back will be glued overnite.

Sep 30, 06 | 1:24 pm
mbbransc

Total Topics: 13
Total Posts: 71
Keith - I am considering the same thing. I have a '63 J-45 Gibson and I was looking at it the other day. Sure as the world, it has a small patch of canvas over that X.

Sep 30, 06 | 7:27 pm
Phlytyer (Keith)

Total Topics: 37
Total Posts: 273
After leaving here last night, I Yahoo'd and Googled "x brace patch". Found some interesting new guitar sites as well as Kathy Mats (at the top of the list).

One link was to Wechter Guitars, "Abe's Column." Here, it is suggested to use a .22 caliber cleaning patch, (which I just happen to have a few on hand).

Oct 01, 06 | 4:13 am
Cogges

Total Topics: 4
Total Posts: 42
I read somewhere that this is to help prevent moisture absorption through the exposed end-grain. I always thought it was a way to cover up a sloppy cut!!! I've built several guitars without the cover, a few with- only time will tell. And, like Keith says, a .22 patch is darn-near perfect for it- a nice piece of clean linen, just the right size.

Oct 01, 06 | 7:34 am
jhowell

Total Topics: 37
Total Posts: 676
Using a piece of spruce to 'cap' the joint is a much stronger method of construction and really doesn't take much extra time.

Oct 01, 06 | 3:04 pm
Phlytyer (Keith)

Total Topics: 37
Total Posts: 273
Sorry Jim; Went ahead and 'glassed' it. (so to speak). Used the .22 patch and LMI glue (shudda p***** used 'poxy). But the damage is done. Progressing nicely, if I say so myself.

Oct 05, 06 | 5:33 am
Ken Cierp

Total Topics: 58
Total Posts: 2262
It is only my opinion ---- but I think the patch is a hide glue thing. I have worked on old guitars that are falling apart because the glue gets too brittle and fails. I have never heard of a tight fitting epoxied joint failing. Also, getting the area too rigid (epoxy glassing) has the potential of restricting movement and sound production --- more is not always better. Guitar top not table top!

Ken

www.kennethmichaelguitars.com

Oct 05, 06 | 12:04 pm
Luthier Suppliers

Total Topics: 2
Total Posts: 68
I was at the ASIA convention a couple of years ago where Ervin Somogyi gave a demo in the class regarding the stiffness of this patch. He mentioned that one of the lady builders had done lots of research regarding how much patch was needed over this joint. She had found that 1/8" thick piece of 1" spruce was plenty of strength for this joint. In fact, you could make it a 1/16" piece of spruce and be fine. Ervin demonstrated how much loss of strength the X brace losses when this patch is missing. Many have said that once they added the patch, their guitars sounded so much better. I think that person mentioned that it was louder. But I'm going by memory here. I always include a thin 3/32" spruce patch about 1 1/2" long over the joint. Never had a problem, and my guitars sound really good.
Tracy
http://www.luthiersuppliers.com

Oct 10, 06 | 6:56 pm
Ken Cierp

Total Topics: 58
Total Posts: 2262
We are entering in the area of what sounds good to one person may not appeal to another – I have some pre-cut braces directly from the Martin factory that I use for measurements --- the joints are in fact pretty sloppy relative to my standards I suppose that if I were to use them I’d indeed do the .22 patch thing. Plus they are all rounded over so using a wood splint would require some carving, which will make them weaker --? Just food for thought, the X brace forward guitars supposedly are prized and sound pretty good. The area under the bridge is weaker than the contemporary design – so is stiffer better? Roger Siminoff would suggest not – sighting the problems that the Gibson double X braces caused relative to sound quality. Putting on my woodworker’s hat (we are woodworkers first) I can say that I would never put a Band-Aid on a joint with four gluing surfaces. With modern adhesives and a tight fit, the joint will be stronger than the wood itself. If my goal were to make the top stiffer, Tracey’s approach would seem to be more scientific and controllable. Without going in the engineering stuff – the reality is that, length, width, thickness, weight, grain direction, stiffness, material, etc. and all the combinations, will in fact impart a different sonic foot print. So keep track of what you did --- it may be the next great design.

Ken

www.kennethmichaelguitars.com

Oct 11, 06 | 4:02 am
mbbransc

Total Topics: 13
Total Posts: 71
LOL!! I desided against any bracing over the X. This is my first build!! If it falls apart, I now have a built in excuse!! ;)


Oct 11, 06 | 6:40 am
blues creek guitars Authorized Martin Repair Ctr

Total Topics: 52
Total Posts: 1011
Simon Partick guitars uses the plate reinforcement patch. I have seen them fail more than I ever did a cloth patch. I agree that the wood patch will make the joint stiffer but I am not looking for stifness here I am looking for support and while it may sound contradictory it really isn't , the top and bracing need to work together . With the bracing glued to the top , the joint is supported by the wood from the top. THe cottan patch will support the joint fine.
Look at the forces applied to the top. Most of the forces are rotational from the strings over the saddle. There isn't that much downward force applied but more tensional from the strings pulling. As the strings pull the top upward , the strings then push the saddle down thus the rotational force. All this while the strings are pulling the bridge in the direction of the neck.
just my 2 cents.


Oct 18, 06 | 6:31 am
Andy

Total Topics: 57
Total Posts: 350
Ervin Somogyi is a name I've never heard of; maybe others here know of him. He must hold some amazing status in the world of lutherie judging by what price his guitars command. I came across this article, http://www.esomogyi.com/principles.html were if you scroll down the text to the paragraph which has "Figure 11" , he discusses his findings on constructing the ultimate x-brace.

Why do I get the feeling that so many aspects of guitar building is like a riddle within a puzzle wrapped in an enigma ? ............................. ;)

Oct 18, 06 | 10:29 pm
jhowell

Total Topics: 37
Total Posts: 676
I hadn't heard of Ervin until a few months ago when some people who had attended one of his classes reported in on another forum. One of my medium term goals is to attend his class on bracing tops. I haven't made nearly enough sawdust yet! My goal is to get ten or twelve scratch builds under my belt before I pony up for the class. Ervin's website is book-marked and I travel there off and on. The more hands on experience I get, the more a lot of what he has to say makes sense.

I'm coming to see that this guitar building stuff is much like a writer finding his/her 'voice'. It has such a lot to do with the doing of it along with a little of the learning about it by reading/watching.

Oct 19, 06 | 2:26 pm



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