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Tricky brace repair
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Author:  Kim [ Sun Apr 29, 2007 2:13 am ]
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Hi all,

I just completed what was, at least for me, a challenging brace re-glue on my old Maton so thought I might share for any noobs that may find themselves in a similar position and decide to have a go at DIY.

This old lady has a double X braced top (mentioned in an earlier thread about bridgeplate nightmare)). The secondary X brace, situated entirely within the lower bout, has legs running across either end of the bridgeplate which junction into the main X bracings as shown.



This really is one guitar that you just would not want to replace the bridgeplate on. However my problem was at the other end of that secondary X brace. (Sorry, no before pic cause I did not think that this would really interest anyone until I had the thing clamped up.) The other end of that brace extends to the very back of the guitar where it meets the kerfed linings a short distance from the side of the tail block on the treble side where it finishes flush and untucked.

It was that end of the brace, near the tailblock, which had come unglued for about 4" and, aside from the obvious negative affects upon tone, it was also threatening to come completely unstuck (just like the repairer) and introduce more dramatic problems.

The challenge?? Not being a little fellow, it was quite impossible for me to reach my arm down to the very back of the guitar because my forearm filled the soundhole about 1/2 way in. So for me at least, this repair was comparable to an elephant trying to extract a teaspoon from a flea's bottom with a crowbar

Even for a smaller person the problem would remain, how do you see what the heck you are doing way back there when your arm is completely blocking any vision via an inspection mirror either through the sound hole, or the bridgepin holes? Also if you cannot reach a brace jack, how do you clamp this sucker once you have cleaned out the old and put in the new glue?? And, to top it off, how once you make a mess way back there working with glue, back to front and inside out in a mirror, how do you then clean up so no-one knows you have been futzing around???

Well ya need special service tools. And number one, (Aside from a small mirror equipped with little blocks glued either side of it's back so it can straddle the back bracings so that you can see that particular part of the top you wish to work on) is a glue application device.



Showing the underside, or that part of the tool that will face down, away from the top of the guitar, this is simply just a piece of feeler gauge epoxied at just THAT angle onto a length of 1/4" mild steel rod flattened at the end and bent just so. These angles are determined via trial and error with inspection light and mirror. For an inspection light, just wire up a small energy saver neon. These run much much cooler than a standard incandescent and the last thing we need is heat building up inside the box softening the good glue which is still holding everything together.

Next, before we apply glue, we need to have ready a clean up device. This one is just another length of 1/4" rod bent just so with a bit of kitchen sponge folded over the end and CA'ed into place.



Now we need to open the joint a little. To do this I used a flat piece of board on the very top placed over the offending brace, just back from the unglued section. This is depressed via a small gobar and the joint opens just nicely.

Once done, you can then apply sufficient glue between the brace and the underside of the top using the rod and feeler gauge tool to deliver the glue into the joint a little at a time. Just be sure to place a bit of paper inside of the guitar to catch any drips from falling on the back before you start.

You then clean up any mess by moistening the clean up tool and scrubbing off the excess glue. Careful not to make the sponge too wet as you do not want to contaminate the glue that you worked into the joint.

Now you just need to clamp this baby. To do this I used yet another length of rod bent just so. First I supported the outside back of the guitar against downward pressure from the inside. Next I placed a flat piece of wood to span the back braces and spread the load upon which will sit the bottom of the bent clamping rod.

To help counter some of the upward pressure from the top from the clamping rod, I left the top just a little depressed using the small gobar I used to open the glue joint. I then carefully maneuvered the end of the bent clamping rod into position to sit directly onto the brace and then levered the brace upward against the top until I could see good squeeze out (To match the rest of the bracing ).




Once in place, I then used yet another gobar on the end of the clamping rod left poking out of the soundhole to hold it's own spring tension between the gobar, the flat piece of wood which spans the back braces and the other end securing the newly glued brace.



Anyhow, whist this method is not very polished and would probably not suit the pro shops (or to steal a phrase from my mate Tim, "it's all a little agricultural") it does indeed work for the one offs

Just remember, dry try all your custom made tools first to get the fit right and be extra careful cause I reckon that the spring loaded clamp I made could easily punch a hole clean through the top if it slipped off the brace.

Just hope this helps someone out there with a similar problem who is surfing the WWW for an answer.

Cheers

Kim


Author:  Mike Collins [ Sun Apr 29, 2007 2:52 am ]
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NICE!!!!!!!!
Great tips also!

I use a feeler gauge also for brace repairs.
And a tunbuckle for clamping.

Mike Collins

Author:  crazymanmichael [ Sun Apr 29, 2007 4:46 am ]
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i've used turnbuckles and toilet paper rollers, machine jacks, etc., but all rquire you to be able to get a hand into the damaged area. long clamps c-clamps such as stew-mac sells are also very useful. i just hot glue an appropriate shaped bondo, or in later years friendly plastic caul to the inside screw pad.

but this is again an example of the improvisational ingenuity for which australia is justly renowned. its isolation has historically made specialized tooling hard and slow to acquire, as well as very expensive, necessitating a self reliant, creative attitude if you wanted to get anything done. nowhere was this more true than on the isolate stations and farms of the west and centre, hence the term agricutural.

and so the tradition still seems to be alive and well in the urban centre of the golden west.

well done kim!!!!

Author:  Cocephus [ Sun Apr 29, 2007 6:28 am ]
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Thanks for the tutorial, Kim!

Author:  Billy T [ Sun Apr 29, 2007 9:45 am ]
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Cool Kim!

Author:  KiwiCraig [ Sun Apr 29, 2007 10:18 am ]
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On Ya Kim , and well done. Where there's a will , there's a way .

Maybe this is a good argument to tuck those Xbraces into the liners !


Cheers Craig

Author:  Kim [ Sun Apr 29, 2007 4:41 pm ]
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[QUOTE=KiwiCraig]
Maybe this is a good argument to tuck those Xbraces into the liners !

Cheers Craig[/QUOTE]

Craig,

I think the problem here was not so much not tucking but rather just glue failure due to heat exposure which occurred before this one came into my hands. When I first got this guitar, the neck had jacked up and collapsed the soundboard back into the soundhole either side of the fretboard, only the plastic rings in the rosette had arrested the neck from pulling up even more.





This collapse had occurred in the main as a direct result of the upper transverse having suffered major glue failure. With the assistance of Frank Ford's most brilliant Frets.com and kind help from Michael (Crazyman) McClain, I was able to affect a good repair and reset the neck.



As for tucked verses untucked my own lack of experience forbids me from commenting too much but If I recall correctly, Mario Proulx suggest that feathering the very end of braces to nothing as it meets the linings avoids the potential for the ends to spring. The braces pictured above have been left around 1/16th" tall and this, combined with the heat exposure may have created the problem.

Cheers

Kim


Author:  CarltonM [ Tue May 01, 2007 5:12 am ]
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Nice work all around Kim! Thanks for the toot. Very inventive. I have to say, though, that if you start doing this professionally, you should change your "repairman's label", seen in the photo above.

Author:  LanceK [ Tue May 01, 2007 6:01 am ]
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SUPER JOB KIM! Man that looks great!
I remember reading about a similar fix in a GuitarMaker Journal not too long ago..


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