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Top and Back Cracks
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10137&t=50976		 Page 1 of 1
Author:  George L [ Sat Sep 15, 2018 9:02 pm ]
Post subject:  Top and Back Cracks
I guess it had to happen at some point: Today I had a guitar return to me with issues. :(

I made the guitar a couple of years ago for my sister, who wanted a special gift for her partner. It's cedar over wenge. I got a look at it today and the top and back are cracking! As the pics below show, there are cracks on either side of the fingerboard extension and several running pretty much the entire length of the back. The back center seam is separating as well. (I couldn't get a good pic of the back. The one I have here highlights a portion of just three cracks--others run parallel to these.) I don't see any damage or dents or other signs of the guitar falling.

He doesn't really play much at all, so it has basically just been sitting in a stand for 2+ years. They live near me, in western Washington state, where humidity issues aren't typically a problem. (I think this was my 14th guitar and I've not had any others crack.) He says it hasn't been near a heat source, or in direct sunlight, etc. I'm somewhat skeptical of this claim, but this is the only time I've used either wenge or cedar, so ... maybe? FWIW, the plates were well-quartered, with near perfect vertical grain and were purchased a long time ago. (Two decades for the top.) They had been acclimated to my workspace for several years.

As a bonus, even though I'm sure I gave him my standard advice about care, he apparently used Pledge to keep it clean. idunno

Anyway, what's done is done. Thoughts on what I can do now? Advice on how to go about repairs? I already told them I doubted I could make the cracks invisible.

Thanks in advance,

George

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Author:  Barry Daniels [ Sat Sep 15, 2018 9:51 pm ]
Post subject:  Re: Top and Back Cracks
The guitar has obviously dried out. Whether that was caused by heated air or the natural climate is hard to say. In the future they should keep the guitar in the case with humidity control and monitoring.

By the way, Pledge is full of silicone and will make any refinishing much more complicated.
Author:  George L [ Sun Sep 16, 2018 9:08 am ]
Post subject:  Re: Top and Back Cracks
Yeah, the use of Pledge is not great news. We shall see.
Author:  dpetrzelka [ Sun Sep 16, 2018 10:17 am ]
Post subject:  Re: Top and Back Cracks
George, Hot hide glue / fish glue, and some TJ THompson style cleats and you'll be set. Then its just hoping that the Pledge didn't get into the crack. Drop fill, level, polish, done. You are welcome to borrow any of my magnetic top/back crack cauls, just send me a message.

I used to think we didn't have much worry in terms of humidity here in the PNW, but in both of the last winters our office has dropped into the high teens, wrecking havoc on a good friend's guitar collection that he keeps there. Popped bridges, cracked top/backs.

If this one was braced on the high side of the 45% target, and the relative humidity drops below 25-30% it can get into that danger zone.
I've have a few friends that I insist keep those cheep hygrometers in their playing rooms, I calibrate it for them, and then give them a % humidity below which they need to put the guitars into cases.
Author:  George L [ Sun Sep 16, 2018 11:25 am ]
Post subject:  Re: Top and Back Cracks
Daniel - Thanks for the clamp/caul offer. I may take you up on that later on. My workspace is a mess right now, as I'm reconfiguring the layout. Will likely be in touch once I get things sorted.
Author:  Haans [ Sun Sep 16, 2018 12:03 pm ]
Post subject:  Re: Top and Back Cracks
Wenge is a wood that I might have treated like my old cracky BRW, kinda brittle and crack prone. Flood with thin CA on both sides and sand off before building with it.
Another thing to be wary of is air conditioning. It will drop the humidity too and dry instruments out....
Author:  George L [ Sun Sep 16, 2018 1:30 pm ]
Post subject:  Re: Top and Back Cracks
I agree, Haans, about the crack-prone nature of wenge. In hindsight, a CA flood might have helped. Also agree about A/C dropping humidity. Not a culprit in this case, as they don't have it in their house. Not many folks around here do, actually.

It doesn't matter but since the Internet is forever, I should set the record straight: This was the 12th guitar I built, not the 14th. :D
Author:  B. Howard [ Mon Sep 17, 2018 6:31 am ]
Post subject:  Re: Top and Back Cracks
The wenge is almost a given, look at it wrong and it can crack. But that top is suspicous.... That fracturing to the treble side of the extension creeps across the grain much more like an impact crack then a typical crack from wood shrinkage. My guess is compression damage. Someone stepped on the guitars or it took a dive in a case. The back cracks fit in with that scenario as well.

You would not believe how often I see guitars with mysterious or "drying" cracks that were actually caused by children, roomates etc and only owned up to after I asked the client and they in turn asked questions.....
Author:  George L [ Mon Sep 17, 2018 10:59 am ]
Post subject:  Re: Top and Back Cracks
I thought that was a bit strange, too. This will be a good challenge and learning opportunity for me.
Author:  Haans [ Mon Sep 17, 2018 12:31 pm ]
Post subject:  Re: Top and Back Cracks
I sure would at least charge cost for that repair, humidity problems or guitar stand accident. Anyone leaving their instruments on stands is just asking for it either way.
Author:  ernie [ Mon Oct 15, 2018 4:29 pm ]
Post subject:  Re: Top and Back Cracks
I have rarely seen a wrc top get cracked indoors , especially in the PNW The only time I/ve seen wrc crack is when it is left out all summer to dry and regain moisture in winter..The constant cycling would cause cracks IMHO.
Author:  Pmaj7 [ Mon Oct 15, 2018 6:04 pm ]
Post subject:  Re: Top and Back Cracks
Dry air from heating can definitely cause cracks here. That's why I try to build in the upper 30s to very low 40s.

New username, same ole Pat Macaluso!
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