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 Post subject: How Repair Cracked Side?
PostPosted: Sun Nov 25, 2012 2:34 pm 
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Cocobolo
Cocobolo

Joined: Thu Mar 19, 2009 10:52 am
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State: PA
Country: USA
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This classical guitar was in its case for 5 years & emerged with a cracked side. There are 2 parallel cracks separated by about 3/4" and about 3" long. The cracks start at the waist and move along the flat area toward the lower (big) bout. The wood between the cracks is pushed in 1/32" or less from the surrounding area. The wood is EIR.

Any suggestions on how to go about this repair & what glue would be best? I have no experience with hot hide glue, but use Titebond, fish glue, & CA.

Attachment:
Crack 1 small.jpg

Attachment:
Crack 2 small.jpg


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PostPosted: Sun Nov 25, 2012 3:05 pm 
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Brazilian Rosewood
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Location: Central PA
First name: john
Last Name: hall
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My favorite glues here are Fish and Hot Hide. You can heat the fish glue but Hot Hide is my first choice.
Is this a French Polish ?
First I want to get the wood aligned. I would clamp lighty and work in the glue, The snug the clamp and Cleat on the inside

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PostPosted: Wed Nov 28, 2012 2:20 pm 
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Brazilian Rosewood
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I hate side cracks, because how would you ever hope to clamp it even?

One time I just lined up the crack and placed a clamp across the side (on the top/back) and slowly tighten as I align it. A quickgrip clamp is essential here and is actually very helpful although a cam clamp can work too. Just enough pressure is needed to close the gap and the jagged edge sort of lock itself together as the glue dries. I favor hot hide glue for most repair work because of its ease of cleanup but I like to use CA for very tight cracks.

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PostPosted: Wed Nov 28, 2012 2:38 pm 
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I had a crack in that very spot. I aligned it, wicked in just a little CA to hold it together, then epoxied a small mahogany patch inside using rare earth magnets to hold it in place while the epoxy cured. Worked like a charm. Just be careful not to glue the magnets in place. DAMHIK.


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PostPosted: Wed Nov 28, 2012 2:43 pm 
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First name: Chris
Last Name: Pile
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Country: Good old US of A
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Best clamp I ever used for side cracks was made from a spare guitar tuner and a few scraps of wood. Got the idea from one of Dan Erlewine's videotapes.

Mount the tuner on a caul you've shaped to fit the body curvature, and have a corresponding cross grain patch on the inside. Drill small holes through them for a guitar string. Put the ball end inside to keep it from pulling through, and you draw the crack up tight by turning the tuner. No need to clamp the sides for most cracks. Use wax paper to keep from gluing the caul to the outside of the guitar. You'll have a small hole to touch up afterwards.

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PostPosted: Wed Nov 28, 2012 5:32 pm 
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Cocobolo
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Joined: Thu Mar 19, 2009 10:52 am
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State: PA
Country: USA
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Thanks for the input. I used StewMac's powerful magnets as a clamp with wax paper under each. They pulled the cracks perfectly closed. Then wicked in some CA. The repair is invisible.


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