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| Back Crack - Smash it? http://luthiersforum.com/forum/viewtopic.php?f=10101&t=42532 |
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| Author: | absrec [ Fri Jan 24, 2014 12:02 pm ] |
| Post subject: | Back Crack - Smash it? |
I just got this thing together. Of course, it has Bloodwood back and sides, which I know is prone to cracking anyway. It sounded pretty good, I must say. Better than any of the acoustics I own. It took me less than a month to build so I guess I'm not out a whole lot in that regard. I'm just wondering what the other folks here would do in this situation. Is it worth trying to repair somehow or should I just run over it with my car and post the video on YouTube? 
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| Author: | bluescreek [ Fri Jan 24, 2014 12:18 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
I think you may have learned your first lesson on RH and what it can do . Do you control RH when you are building ? |
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| Author: | Mike Collins [ Fri Jan 24, 2014 12:22 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
two things come to mind. The Bloodwood was not dry enough to use. Or the Slab Maple pulled it apart because the maple which is tough shrunk & caused the Bloodwood to crack. replacing the back is not that difficult. Cut the bindings off to expose the glue joint & use a warmed thin blade to separate the joint.A bit of white vinegar will help -just mix it with warm water. NOT allot-just 1 teaspoon to 1 cup of water. The neck & butt blocks will be the most difficult to loosen, because of their size. Just my 2 cents Mike |
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| Author: | Michael Lloyd [ Fri Jan 24, 2014 12:37 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
If it sounded pretty good. Fix it. Looks like an end drop to me. Easy fix if the neck to body joint is not misaligned. Dry fit the crack first. Hide glue the crack then apply glue of choice to bracing. |
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| Author: | nyazzip [ Fri Jan 24, 2014 12:56 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
rather than smashing it, you could probably practice some cleat-laying techniques on it if you can get the gap squeezed shut, no? |
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| Author: | WudWerkr [ Fri Jan 24, 2014 1:09 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
My concern here is , if the back was braced and glued properly how did that wide of a crack happen? Logic dictates that the glue joints on the bracing came loose as well or that the braces are damaged . Or am I way Off Base here ? 
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| Author: | absrec [ Fri Jan 24, 2014 1:14 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
bluescreek wrote: I think you may have learned your first lesson on RH and what it can do . Do you control RH when you are building ? LOL!!!!!!!!! No.... I build in my garage. You make a good point though. The dew point is -2 deg F in Atlanta at the moment. RH is 20%. I guess maybe it would help if I understood the first thing about how RH relates to acoustic guitars. I've only ever learned how it affects finishing. |
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| Author: | absrec [ Fri Jan 24, 2014 1:22 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
WudWerkr wrote: My concern here is , if the back was braced and glued properly how did that wide of a crack happen? Logic dictates that the glue joints on the bracing came loose as well or that the braces are damaged . Or am I way Off Base here ? I don't think you're off base. I don't really know honestly. I glued it with go bars in a radius dish. I used Titebond 1. It seems that I have a tendency to push the open working time of that glue so perhaps I pushed it too far. The bracing is totally separated. At least #'s 2&3. Can't see the other two. |
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| Author: | absrec [ Fri Jan 24, 2014 1:26 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
One thing I should mention is that the blood wood on the back with thicker than the blood wood sides. The sides were thicknessed down to around .07" so they would bend. The maple seemed very cooperative comparatively speaking to the strip of Bloodwood going up the middle of the back. |
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| Author: | the Padma [ Fri Jan 24, 2014 1:28 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
Yo absrec, That looks like a really nice rose stem to me. Just inlay a dark strip , add the rose and a few leaves, and raise the price on the sucker. Is true that Bondo works magic but not for this.  Or you could make a patch, screw it down flat with some round head brass screws, pollish them up and call it your "Steam Punk Model"  Well is just an idea dude.Both of me suggestions would probably be far quicker than pulling the back and remaking it. Finally, cleating a crack of that nature closed does nothing for the existing tensions in that box and they will more than likely only open up elsewhere. With all that said...you really only gotts two choices. Replace or disguise. Blessings  ?adma
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| Author: | WudWerkr [ Fri Jan 24, 2014 1:30 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
absrec wrote: WudWerkr wrote: My concern here is , if the back was braced and glued properly how did that wide of a crack happen? Logic dictates that the glue joints on the bracing came loose as well or that the braces are damaged . Or am I way Off Base here ? I don't think you're off base. I don't really know honestly. I glued it with go bars in a radius dish. I used Titebond 1. It seems that I have a tendency to push the open working time of that glue so perhaps I pushed it too far. The bracing is totally separated. At least #'s 2&3. Can't see the other two. What ever you decide to do, use it as a learning model .. I would remove the back and determine what caused it . I am leaning toward RH as the main factor . |
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| Author: | SteveSmith [ Fri Jan 24, 2014 1:32 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
I would say by all means Fix It. As Wud said, use it as a learning experience. |
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| Author: | absrec [ Fri Jan 24, 2014 1:46 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
SteveSmith wrote: I would say by all means Fix It. As Wud said, use it as a learning experience. I'm still a bit undecided on this. While I always tend to jump at a good learning experience, there are more issues with this guitar than the "rose stem" up the back. Yes, it does sound pretty good but there are other things that could be better. Things I learned along the way. The neck angle is too steep, for instance. I ended up adding a shim to the under side of the bridge to compensate and the saddle is probably still too high. All of that said, it still sounded pretty darned good. Up until now, I've concentrated more on things like voicing, purfling, binding, etc. just getting that stuff right. If the sound is any indication, I think I got the top and back voicing into a more-than-acceptable range. When I was playing earlier, before noticing the crack, I said to myself "It sounded better yesterday". Today, it just sounded thin and hollow which gives me a indicator of what purpose the back was serving. |
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| Author: | Clay S. [ Fri Jan 24, 2014 1:57 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
Since the bloodwood is a wedge shape you could try just loosening the bindings, removing the bloodwood, reglue the back braces to the now accessable maple, fit a new wedge, and reattach the binding ends. Some might not even loosen the bindings -just fit a new wedge. Do it while the humidity is low. You might also be able to tweak the neck angle with the wedge removed. |
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| Author: | the Padma [ Fri Jan 24, 2014 2:13 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
nyazzip wrote: rather than smashing it, you could probably practice some cleat-laying techniques on it if you can get the gap squeezed shut, no? NO nyazzip...he could do that, but the answer is a definite NO! Nor am I going to go into the reasons. nyazzip... for the third time me, ?adma is calling your card.Since you joined this site, You been passing out a lot of sarcasm, answering questions with opinionated BS information and talking it up like you an old pro loofer . Me believe you are just a~wanna~be with a big mouth trolling this forum. Me may be wrong...but me no thinks so. Again for the third time ....show us your build pics or shut up. . |
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| Author: | nyazzip [ Fri Jan 24, 2014 2:28 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
...go into your yurt, touch your crystal, and maybe you'll have a vision of my woodworking, O Spiritual One. not sure what part of "amateur" you don't get. |
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| Author: | the Padma [ Fri Jan 24, 2014 2:42 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
nyazzip wrote: ...go into your yurt, touch your crystal, and maybe you'll have a vision of my woodworking, O Spiritual One. not sure what part of "amateur" you don't get. POST PICS OR STFU |
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| Author: | RusRob [ Fri Jan 24, 2014 3:01 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
I want to see the YouTube Video myself... As a repair guy I would have to say if you built this at 20% humidity there is probably no saving it... It will develop other problems for sure and if you say the neck angle is wrong and the bridge is shimmed... There probably isn't much sense in trying to fix it. My best suggestion would be to disassemble it and use the wood to build a parlor guitar.... Or... make that YouTube video. @ ?adma,Why would you say such a mean thing? Here all along I thought you were a really nice guy Bob |
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| Author: | WudWerkr [ Fri Jan 24, 2014 4:12 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
absrec wrote: WudWerkr wrote: My concern here is , if the back was braced and glued properly how did that wide of a crack happen? Logic dictates that the glue joints on the bracing came loose as well or that the braces are damaged . Or am I way Off Base here ? I don't think you're off base. I don't really know honestly. I glued it with go bars in a radius dish. I used Titebond 1. It seems that I have a tendency to push the open working time of that glue so perhaps I pushed it too far. The bracing is totally separated. At least #'s 2&3. Can't see the other two. There have been several threads on here about glues , might do some reading . "IF" I remember correctly , Tite Bond Orig. has been recommended and that there IS a shelf life on that glue as well . ... Of course my memory isnt what it used to be And this is a Family Forum , so NO Crystal Touching !! 
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| Author: | John Arnold [ Fri Jan 24, 2014 5:14 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
Quote: if you built this at 20% humidity there is probably no saving it. That is not what happened. It was built at much higher humidity, and now it is at 20%. Wood shrinks when it gets dry....that is all you need to know. If you glue on the braces at high humidity, and then expose the guitar to low humidity, it wants to shrink, but cannot because the bracing is holding it. That is because wood moves very little parallel to the grain....braces don't move, but the top and back want to get narrower or wider. Quote: I don't really know honestly. I glued it with go bars in a radius dish. I used Titebond 1. It seems that I have a tendency to push the open working time of that glue so perhaps I pushed it too far. It has nothing to do with the Titebond. |
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| Author: | RusRob [ Fri Jan 24, 2014 5:44 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
John Arnold wrote: Quote: if you built this at 20% humidity there is probably no saving it. That is not what happened. It was built at much higher humidity, and now it is at 20%. Wood shrinks when it gets dry....that is all you need to know. If you glue on the braces at high humidity, and then expose the guitar to low humidity, it wants to shrink, but cannot because the bracing is holding it. That is because wood moves very little parallel to the grain....braces don't move, but the top and back want to get narrower or wider. Quote: I don't really know honestly. I glued it with go bars in a radius dish. I used Titebond 1. It seems that I have a tendency to push the open working time of that glue so perhaps I pushed it too far. It has nothing to do with the Titebond. Maybe I read what absrec said wrong but I think he said he just put it together. Quote: I just got this thing together. Yes that was the first line of his post.He also said he worked in his garage and didn't really know much about RH except having to do with finishing. Quote: bluescreek wrote: I think you may have learned your first lesson on RH and what it can do . Do you control RH when you are building ? LOL!!!!!!!!! No.... I build in my garage. You make a good point though. The dew point is -2 deg F in Atlanta at the moment. RH is 20%. I guess maybe it would help if I understood the first thing about how RH relates to acoustic guitars. I've only ever learned how it affects finishing. He did not say he built it at 45% RH so I assumed he built it at low humidity in his garage. I am not sure where you read he built it in normal humidity but either way, he did say the neck angle was wrong and the bridge was shimmed as well as some other issues so in my opinion his time would be better spent building his next one and save the wood from this for another. But that is just my opinion and people can take it as just that... Cheers, Bob |
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| Author: | Jeff Highland [ Fri Jan 24, 2014 6:03 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
The very nature of the failure (a big separated crack and detachment of braces) is telling us that it was built in much higher humidity than the current 20% |
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| Author: | RusRob [ Fri Jan 24, 2014 6:47 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
@Jeff Highland and John Arnold, I guess after thinking it through that is correct and why it developed such a gaping crack. Maybe getting it back to normal humidity will close it up... Probably not but would be worth a try. Cheers, Bob |
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| Author: | absrec [ Fri Jan 24, 2014 7:20 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
This is Atlanta. We typically have high humidity. Sometimes even in the winter months. It's a royal PITA when it's time to spray finish. This winter has just been a little out of the ordinary. A few cold snaps that were colder than normal. One just hit us yesterday. Figures. |
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| Author: | Clay S. [ Fri Jan 24, 2014 8:02 pm ] |
| Post subject: | Re: Back Crack - Smash it? |
"This is Atlanta. We typically have high humidity. Sometimes even in the winter months." That is why I say regluing your back braces and replacing the center panel while the humidity is moderately low may work if the rest of the guitar hasn't come apart. A relatively small tilt of the neck will correct the high bridge problem. "Slipping the endblock" was a semi quick and dirty way to reset necks once upon a time. When you remove the center wedge you will be able to set things right, and gluing in a new piece will hold them there. |
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