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Hair line Crack on my Curly Redwood
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Author:  utarazo [ Tue Feb 07, 2012 1:38 am ]
Post subject:  Hair line Crack on my Curly Redwood
I am starting my third build. A Claro Walnut/ Curly Redwood. I glued the tops and back today, and as i was cleaning up i accidentally droped my top on the floor, when i picked it up there seemed to have been a hairline cracks on the soundboard. My question can i still use this sounboard or should i put it aside and use another set of Curly redwood!? also since I'm just starting, would the curly redwood complement the claro walnut? I have sets of Adirondack, Lutz, Redwood, Cedar, Carpathia. so i wonder if by any of youlls experiences, if walnut works better with something else?. The curly redwood i have is striking though! wow7-eyes

Jonathan

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Author:  DennisK [ Tue Feb 07, 2012 3:20 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Where is the crack in relation to the bridge? I would think directly behind would pose the greatest risk of crackling apart under tension.

I haven't worked with curly redwood yet, but I did drop my straight grained top and made a nice big crack, which glued right up http://www.luthiersforum.com/forum/viewtopic.php?p=458394#p458394

Most likely what I would do is slop some thin hide glue on it, which should wick in and swell the wood to close the crack. Then let it cool for a minute, scrub the excess off as best you can with a dry paper towel (don't add any water or it might wash out the glue in the crack), and scrape clean after it dries. In fact, it may be beneficial to to give the entire top a coat of thinned hide glue, to soak into the end grain. Otherwise the crack area might look a little different even after scraping, depending on how deep in the glue soaks. Also might help bind the fibers together more strongly, and clog the end grain so it doesn't soak up too much of whatever finish you put on it. According to Ervin Somogyi's French polishing notes, Eugene Clark always does a hide glue wash coat followed by light sanding before going to shellac.
Author:  Tony_in_NYC [ Tue Feb 07, 2012 6:29 am ]
Post subject:  Hair line Crack on my Curly Redwood
You should flex the crack open a bit to get the glue into it. If you get some squeeze out on the other side you know you got good glue penetration and you should be fine.
Author:  TonyKarol [ Tue Feb 07, 2012 8:13 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Thats one of the reasons I wont use the stuff anymore .. too risky.

That said, my first curly redwood top had a couple of the same cross grain fractures in it. Not from dropping it, just there. I flooded the whole top with CA prior top finishing .. still holding up today, and that was 8 years ago.
Author:  jfmckenna [ Tue Feb 07, 2012 11:09 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
I don't use it anymore myself except for a double top. Like Todd I've seen those cracks just as they are there for no reason. It's very brittle and unpredictable. Having said that I have not yet had to re-top the one I sold about 5 years ago so that's good. I didn't use CA but in hindsight it's probably a good idea.
Author:  Bobc [ Tue Feb 07, 2012 8:11 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Jonathon that top looks troublesome to me. Wide grain lines light color usually goes along with poor longitudinal stiffness. I'm just guessing at this from my experience cutting curly redwood. If the long grain stiffness is poor I would laminate it to thin spruce and not use it as a stand-a-lone top. Todd is right. Those cracks will show. Not all redwood is troublesome. There's redwood and there's redwood!
Author:  alan stassforth [ Wed Feb 08, 2012 1:02 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
I don't think that is the result of dropping it.
I bet those cracks were there,
and you didn't notice them.
I would say kiln dried?
Yup.
Some call it kill dried.
It would make a lovely electric guitar cap!
Author:  afwonger [ Wed Feb 08, 2012 11:50 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
When you talk about flooding the top with CA, do you just brush it on and then sand? I assume you do it after the box is close... Would doing only one side be good enough?

I was think about using epoxy (a little more flexible than CA, I assume) on both sides before closing the box. Would that make the soundboard too heavy? Thoughts?
Author:  dpm99 [ Wed Feb 08, 2012 12:07 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
To help with the other question, in my very humble opinion, Walnut and Redwood are an amazing combination. To my ears it just doesn't get any better. I don't have the skill to execute what others have achieved with it, but it can be really, really pretty.
Author:  TonyKarol [ Fri Feb 10, 2012 10:37 am ]
Post subject:  Re: Hair line Crack on my Curly Redwood
When I flooded the top, I simply squirted some on, then pushed it around with some wax paper. do it until the colour looks even. No need to do both sides, any fractures will have the glue seep right thru. Then I lightly sanded back, then started the finish.
Author:  Steve Kinnaird [ Fri Feb 10, 2012 1:51 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
I was going to say discard it...until Tony's comment, which gave me pause.
His approach will probably work, knowing though --like Todd said-- you'll always see the crack.
Alan's idea was also great--make an electric.
But if this is just the 3rd build, perhaps you should use something that you are confident in.

Steve
Author:  Tony_in_NYC [ Fri Feb 10, 2012 2:11 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Doesn't CA stain redwood? If so, do you have to cover the entire top with the CA to avoid patches of staining?
Author:  afwonger [ Fri Feb 10, 2012 2:44 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Tony_in_NYC wrote:
Doesn't CA stain redwood? If so, do you have to cover the entire top with the CA to avoid patches of staining?


Also, are there other options besides CA?
Author:  TonyKarol [ Fri Feb 10, 2012 2:59 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Does it stain .. yes .. thats why you need ot do the whole top. Anything other than CA - nothing but water will penetrate and find hairline fractures like CA will .. as for HG closing it up - maybe, but will it go right thru the crack like CA will - I doubt it.

Here is what it looks like after its all said and done .... this one didnt have any fractures I could see, but it got the CA treatment anyway.
Author:  Tony_in_NYC [ Fri Feb 10, 2012 3:17 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Thanks for the info Tony. That's one pretty guitar!
Author:  afwonger [ Fri Feb 10, 2012 5:16 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Tony, did you find that the characteristics of the soundboard changed after the CA? And do you think this can be done before braces are glued to the soundboard?
Author:  TonyKarol [ Fri Feb 10, 2012 6:14 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Cant really say .. never paid much attention to that to be honest -it needed to be done. It was done after the guitar was together, just before finishing .. it still tapped realy well.
Author:  Bobc [ Fri Feb 10, 2012 7:01 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Gorgeous Tony
Author:  TonyKarol [ Fri Feb 10, 2012 9:26 pm ]
Post subject:  Re: Hair line Crack on my Curly Redwood
Thanks all .. I think that was one of yours Bob ...
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