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center seam crack repair when cleats fail
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Author:  JasonM [ Sat Jan 16, 2016 12:56 pm ]
Post subject:  center seam crack repair when cleats fail
I have a Larrivee in the shop with a failed center seam.

It has been repaired once, by another, with what looks like the hydration/ work in glue/ clamp/ cleat method. The repair looks reasonable, but the guitar was allowed to dry out again, and it has reopened.

Looks like it was cleated with CA.

My thoughts were to:
-remove the old cleats
-sand off the superglue
-hydrate until the crack closes
-work in titebond original, clamp
-re-cleat

Although, given this was already done, and I'm not sure what glue was used in the crack, it may not adhere well, and simply fail again. This would lead me to a much more intensive repair, with cutting out the seam, and inlaying a new strip of spruce, levelling, darkening for color match, airbrushing nitro (has the 1982-1994 label, assume nitro during that period?), sanding and buffing out.

The bridge is lifting as well, so will need to come off regardless.

Any suggestions?

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Author:  david farmer [ Sat Jan 16, 2016 1:29 pm ]
Post subject:  Re: center seam crack repair when cleats fail
A center seam and a lifting bridge may point to a," heating event".
Often after a roasting the top will never return to it's original size. Overhumidifing to glue a crack won't help. I would wait and see what the gap is after the top has reached equilibrium at 40-50%.Only then can you decide if a splint is the way to go. Cleats are to reduce flexing of the glue joint, not to hold it together across the grain.

The bridge re-glue at least makes terminating the end of a splint easier if it's needed.
Author:  Hesh [ Sat Jan 16, 2016 1:35 pm ]
Post subject:  Re: center seam crack repair when cleats fail
gaah [headinwall] [headinwall] [headinwall]

Hey Jason!

Sometimes cracks don't want to stay closed even if the prior work was pretty good because of dimensional instability in the materials AND not doing what it takes to keep the instrument hydrated.

At times even when we can get a crack to stay closed if the instrument is overly sensitive to RH swings OR being abused and no instrument would survive without cracking what it has to endure fixing one crack successfully may lead to new cracks somewhere else.

Clearly this one has been permitted to dry out but it's also likely that the customer education regarding RH may not stick either since they already cracked it once and now again....

When this is the case I would favor filling the crack over regluing it and cleating.

If you concur Frank has excellent toots on his site, FRETS.net about adding wood to a open cracked top. This approach will reduce and possibly eliminate some existing stresses that are being exploited by abuse.

On a related note one of the top repair guys at Elderly has pioneered the use of all things ep*xy that is colored to fill open cracks and then a cleat of sorts, much like a mini BJR, back joint reinforcement is also added inside the box. I know what some might say about an ep*xy fill but I personally have seen this done a number of times and can attest to how well it works and if done well can be pretty hard to spot too although it will be noticeable just not glaring.

Once advantage of the ep*xy fill method is no refinishing is required and that's huge!

Hope something here helps you out.
Author:  AndyB [ Sat Jan 16, 2016 3:33 pm ]
Post subject:  Re: center seam crack repair when cleats fail
Just some food for thought. I'm not sure I'd go with Titebond as you can't do anything with it but clean it out completely if you have to be there again in the future. I suspect if you hydrate it will close, you will repair, and it will come back again ... since it's been repaired before. You could always give it a try I suppose. A full spline is more work, for sure, but will most likely be a permanent solution, especially given the bridge is coming off. A wedged spline, fish or hide glue, some careful scraping and a bit of trickery with finish and it will look like a million bucks. Is the top flattened out by chance? Any other signs of what happened?

Nice photos by the way, and best of luck ... let us know how it turns out.

Andy
Author:  wbergman [ Sat Jan 16, 2016 4:10 pm ]
Post subject:  Re: center seam crack repair when cleats fail
My son had a new Laravee 12 string about 20 years ago. The bridge immediately separated and the only thing that kept it from flying under tension was all the bridge pins. I have heard that was not too uncommon with Laravee. One reason I was told was that they glued the bridges on over the finish. The dealer repaired it and it turned out fine.

The point is, the bridge lift and the seam crack could be unrelated to each other, for what that is worth.
Author:  JasonM [ Sat Jan 16, 2016 5:21 pm ]
Post subject:  Re: center seam crack repair when cleats fail
AndyB wrote:
Just some food for thought. I'm not sure I'd go with Titebond as you can't do anything with it but clean it out completely if you have to be there again in the future. I suspect if you hydrate it will close, you will repair, and it will come back again ... since it's been repaired before. You could always give it a try I suppose. A full spline is more work, for sure, but will most likely be a permanent solution, especially given the bridge is coming off. A wedged spline, fish or hide glue, some careful scraping and a bit of trickery with finish and it will look like a million bucks. Is the top flattened out by chance? Any other signs of what happened?

Nice photos by the way, and best of luck ... let us know how it turns out.

Andy


Yes, the top is flat, but I think the are built dead flat, so if they dry out there is no dome to forgive a bit of shrinking.
Author:  alan stassforth [ Sun Jan 17, 2016 7:21 pm ]
Post subject:  Re: center seam crack repair when cleats fail
Isn't it strange that there is no reinforcing at the glue joint?
Author:  Don Williams [ Sun Jan 17, 2016 7:55 pm ]
Post subject:  Re: center seam crack repair when cleats fail
Love the cleat grain going the wrong direction...
Author:  Alex Kleon [ Sun Jan 17, 2016 8:11 pm ]
Post subject:  Re: center seam crack repair when cleats fail
Don Williams wrote:
Love the cleat grain going the wrong direction...


I was going to mention it, until I remembered that I did the same thing on my guitar. Good thing I noticed it. Unfortunately, it was after I closed the box. :oops:

Alex
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