top crack repair

[Shane Haywood]

Frank, Gentlemen

I need a little advise please.

I have an old  1966 Martin D12-20 that has developed a hairline crack in the top from the bridge to the bottom of the top-you could feel it raised up some at the crack-not much light came through when a light was place inside and none closest to the bridge before humidifing.  I have re-humidified it and it is ready for repair.  This crack is where the two matchbook section meet at the seam-the top seam.

I plan to respray the guitar with nitro lacquer.  I have heard suggestions of CA glue, titebond, hide glue and epoxy-tinted to match the grain to fix the crack.    Also use  cleats, or no cleats?  I am concerned about starting out with the wrong glue and not being able to do an additional repair in the future  if needed and well as adversely affecting the tone quality by the glue or cleats.  I am leaning toward CA glue and no cleats but would love some expert advise.

Thanks Shane

Tucson

[Hesh Breakstone]

I would not use CA and would use Titebond original, extend or.  This is not a difficult repair and not uncommon either.

I would also use cleats and you show me someone who thinks that they can hear... a well made, minimalistic cleat and I will show you someone who's smoking the drapes and not sharing.....:)

I would also say that respraying is not necessary.  A well done, completely level crack repair will barely show at all and if it does the finish can be touched up with much less effort than respraying.

One last thing.  In our experience if the crack will not remain closed on it's own at 45% RH after several days at that RH and if it remains very open it may be a candidate for filling instead of gluing closed.  Gluing cracks closed on instruments with permanent dimensional instability only encourage new cracks elsewhere after we force close the existing crack.

[Hesh Breakstone]

I forgot one thing.  This is a classic crack that results from the instrument being permitted to dry out.  I see where you are located too which corresponds with my theory.  Be sure to add a quality case humidifier into this instruments life and/or a decent RH solution for where it lives.

[LARRY KLOSE]

What Hesh say.  I had a dryness crack repaired when I moved to Tucson.  Humidification reversed most of the visual damage and the visibility of the repair is near zero.  In my situation, the crack was near the bass edge of the lower bout and the repair is virtually invisible.  I had a pro do it and it wasn't that expensive.  Lesson learned and now we have a whole house humidifier.  No dryness problems since.

[Shane Haywood]

Thanks for the reply Larry-I appreciate it. I just forgot to water this guitar that was in a closet.   If you're still in Tucson and ever want to get together and play a little then give me a call.  We could hear how this guitar sounds when I get it back together.

[Shane Haywood]

Thanks for the advise.Titebond over CA makes sense.  I plan to spray lacquer for other reasons-we'll see  if I do.  As for the humidification-the guitar was torn down in a closet-neck and fingerboard off-installing an adjustable truss rod. I forgot to water it when I watered my other guitars.  I know some people would not agree with the truss rod but it needed a neck reset and the neck was bowed like a banana.  You do that much work to a guitar, it's not much further effort to make it look good also.  Ultimately, I would like it to play good, sound good and look good also.  Thanks again.