which glue ?

Construction and repair of Classical Guitar and related instruments
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which glue ?

Post by Murat » Tue Oct 03, 2017 12:41 pm

Dear Friends,



I hope to find an experienced answer from the Luthiers and experienced guys in this group. I am confused which glue to use for this crack ? small one on the top near the neck side. the crack not penetrating the sound hole. i have two glues in hand now and really appreciate your advice which one to use ? the finish is lacquer the commercial one I think the guitar is Rameriz Anos 130 not a high end one but it is a great guitar though.

1. GlueBoost ultrathin CA
2.Hide Glue

Many thanks in advance


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robin loops
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Re: which glue ?

Post by robin loops » Tue Oct 03, 2017 3:59 pm

Definitely use the hide glue. CA becomes brittle (more so with time) and does not do well with expansion and contraction (as wood humidity fluctuates) and isn't the best option when exposed to vibrations. It also doesn't adhere woods very well. The fumes from CA can also damaged finish on areas near where you apply the glue and it's much trickier to work with. Also if future repairs require you to remove the glue from this repair, hide glue will be much easier to remove.
One Ring to rule them all, One Ring to find them, One Ring to bring them all, and in the darkness bind them.

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Re: which glue ?

Post by Laudiesdad69 » Tue Oct 03, 2017 11:13 pm

I had a crack in the same area on one of my guitars. After rehydrating it and getting the crack to close, I used CA glue a on the crack. The crack just sucked the glue in, and I did multiple applications until it was even with, and in, the poly finish. Then I wet sanded, and buffed the top. It was a practically invisible repair.

Rehydrating the wood was really important because the fretboard had shrunk, and took the top with it. And the crack was almost able to take a dime, we'll at least it was half a dime. The fret ends were sticking out past the fretboard before the repair and after three weeks of humidification, I only had to smooth two fret end . It was in 17 to 25 percent humidity for a few weeks when it cracked..

Had the guitar not been a Cordoba with a poly finish, I would have used better glue. I also don't like using CA glue on laquer.

Douglass Scott
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Re: which glue ?

Post by Douglass Scott » Wed Oct 04, 2017 3:53 pm

The proper fix:

A) Be sure the guitar is acclimated to an average relative humidity level for where you live or 50% relative humidity.
B) Use hide glue
C) If the crack is open, cleat from underneath if possible (ie. no braces under fingerboard that make it impossible), and glue a splint of the same wood as soundboard into the crack to fill the gap.
D) Clean up glue squeeze out with damp cloth, scrape/sand the splint flush with top without thinning surrounding finish.
E) Once the repair is done you can use CA glue to touch up the lacquer finish. Drop it into the repair to level with surrounding finish, scrape/sand level, then buff and polish. Can be done in very little time.

The above takes a lot of practice to do well. Frank Ford's Frets .com site, I believe explains a lot of the techniques.

Good luck!

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Re: which glue ?

Post by Philosopherguy » Sat Oct 07, 2017 2:59 am

That is too bad to hear that your Ramirez cracked like that. I remember you just got it not too long ago. You have to watch the humidity and make sure it doesn't get too low, or too high either. Hopefully, you can get it all fixed up so that there aren't any other issues. The crack that you show in your picture won't affect your ability to play it at the moment though. You shouldn't have any problems right now. Humidify the guitar up to a good 50% and see what happens!

2013 Ramirez 130 Anos - Spruce
2013 Ramirez 4NE - Cedar
1998 Dean Harrington - Spruce
1977 Kuniharu Nobe - Spruce
1971 Yamaha GC3 - Spruce

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