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While flexing my WRC top I thought I heard a crack, but at the time could not find anything. Now I see there appears to be a hairline crack right at the center seam, running for about an inch from the rosette down. The crack does not go through to the back of the soundboard, and is not separated at all. Note, this is a soundboard with the rosette already inlaid and the soundhole cut. It is for a classical, so it is in the area where the lower cross strut will be, and the upper end of the center fan brace. There will also be a soundhole graft. Is it ok to just rub some glue into the crack and go ahead and use it, and if so, what type of glue would be best? Or have I trashed this top? Wendy

Good Morning Wendy,

Is the crack in the glue joint or next to it? If it is in the joint then it will depend on what type of glue you used. If it is hide glue, flex the crack open and rub some more hide glue in there. If it is Titebond or LMI white type glue, try ironing it with a clothes iron.
If the crack is not in the glue joint then flex the crack open and rub in some glue.

Steve

I would locate the crack, warm the piece with a heat blanket on low, and flow in some very thin hide glue and tape it closed to clamp.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Yes Steven, the crack appears to be in the glue joint and I used fresh Titebond to join it. I say fresh because I checked the number code on the bottle when I bought it. If I warm it with an iron, should there be enough glue already in there to soften and rejoin the crack? After I read your reply I thought about the possibility of rubbing some titebond in and then laying wax paper over the crack and ironing. Does this make sense or should I just iron as is? I'm assuming that since I used Titebond originally I would not be able to repair it with hide glue now. I guess this is a good reason to start using hide glue in the future. Thanks, Wendy

if you warm titebond it will soften but when it cools you don't have a good joint.

If your crack is on the joint itself rejoin it. you could either cut it down the center and redo the joint, or warm it, pull it apart and then joint it and reglue it.

If the crack is not on the center I would use the hide glue method it will be invisible as long as the joint closes up tight.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

With the rosette already installed, a rejoint will not work. The top may be toast. Sorry

Please dont use wax paper. You don't want wax anywhere near your wood!

I use it all the time. No wax transfer occurs when using waxed paper. You can even bake with it, and wax does not transfer to the food. I see no issues. Many folks use waxed gluing cauls so the glue will not stick. No issues that I know of.

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Waddy

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It does appear to be in the joint itself, but I will have to take another close look at it this evening. It is just below the rosette and does not go through to the back of the soundboard, and I can't make it spread any further by some pretty hard flexing, so I think that structurally it would be ok. As I said, it is also over the area that would be reinforced by the soundhole graft and the upper cross strut. I'll have to look with magnification tonight to see if it is actually in the joint. Rejoining would be out of the question, since the rosette is inlaid, the soundhole is cut, and the outline of the guitar is already cut with just a small amount of extra. I suppose it could be done, but in all likelihood if I can't use it It will become bridge pads and soundhole grafts. The consensus seems to be either rejoin or it is toast. Not what I wanted to hear. Wendy

Well Wendy,

If this top were on a 20K instrument and the crack showed up...well you bet that some high end repair luthier would fashion a splinter to deal with it.

So if the various gluem up suggestions don't work...perhaps practicing your fine surgery skills may be in order. Depends on how much that top was worth in the first place.

Sorry this happend to you. I was just dry fitting a mortised neck to the box and heard "the crack" Your lucky, yours was easy to find. Oh well.

blessings
the
Padma

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You can easily test this for yourself. Fold a piece of wax paper and slide a facial tissue into the fold, so that half the tissue is exposed to the wax paper. Iron with a clothes iron on high heat- high enough to soften glue. Check for any difference between the tissue exposed to wax, and the half that was outside.

Wax paper at room temperature is another matter entirely- I use it a lot. BTW, clear packing tape also makes a good non-stick coating for gluing cauls- epoxy will not stick to it.

Cheers
John

Hockey sock tape works great as well. No glue sticks to it that I've found. Cheap too. I bought 8 rolls at Costco for less than $5.00

you could just turn it over and put the rosette in the other side and put a donut over the old one. I wouldn't sell a guitar I used this trick on, but if it is just for you it will work fine.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

Hockey sock tape?

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Say what you do, Do what you say.

I guess it's a Canadian and Northern States thing Dave.

Once you get your knee pads on and the socks over top, standard procedure is to give an upper and lower wrap of stretchy poly tape to hold things in place.

-Agree with what Brock Poling said. The notion of junking a soundboard because of this is.. unfortunate.
Fix it and move forward, feeling lucky you have that piece of wood is my modest suggestion.

It's just clear stretchy athletic tape.. Same stuff you use for football...

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I sat and stared at it for a while last night and then realized that I would always be concerned about it if I used it, so I decided to cut and rejoin. There will be enough leeway to change plans and use it for a smaller Torres body instead of the larger Rodriguez that was intended. I can rerout for a rosette and the only thing different that I will have to do is bind the soundhole. That leaves me needing to buy a soundboard. The ones I have been using have been in my shop for years. If I buy a soundboard now, how long should it be in my shop before I can work with it? Thanks for all your help so far. Wendy

Unless you are really old school and use pieces of tire innertubes.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

In that situation, I try to buy one from another builder who has had it for a while.

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Brock Poling
Columbus, Ohio
http://www.polingguitars.com

I've used parchment paper (also for baking) and had no issues with the glue sticking.

Sounds like you made your decision but providing you could fix it invisibly I dont really see the structural issue with a soundhole donut butting up to the transverse brace and the centre fan brace running the length of the seam I would proceed. This would be a different issue in an X braced steel string