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 Post subject: Update on the Glue study
PostPosted: Sun Feb 10, 2013 1:54 pm 
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Location: Hegins, Pa
Glue Study

In order to make this scientific we will be using 2 independent people to make a "top" sample. The tester will also be independent so no one will know who did what until the testing is complete. We had input from John Reid, a professor of Physics at Lock Haven University and Alan Carruth.
We will be testing a top sample of spruce and mahogany. Phillip Ball, an engineer, and I will be part of the top construction team. Jigs will be used for all the brace placement and clamping.
After Brian Howard tests the samples, the data will be assimilated by John Reid and his team. I hope to meet with Brian and Phillip within the next 2 weeks. The scope of the test will be written and the end results will be posted here.
I look forward to the end results.

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Blues Creek Guitars Inc
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http://www.bluescreekguitars.com


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PostPosted: Mon Feb 18, 2013 7:07 pm 
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Location: Hegins, Pa
An update
we will be making this a double blind study. The testing area will not be in the strength of the glue , that we feel has been done . The test will be in the amplitude and decay of a sample given a particular load as in a guitar. The construction of the samples will be controlled to exclude as many variables in the process as possible.
What is expected is unknown until the test results are complied. The measurements will be of the amplitude and decay of the wave generated by a mechanical means and measured . Also the test will be repeated to see if the results change from duration of excitement.
No one will know who made the samples or the glue used on the samples until the study is completed. If anyone would like to add some input please feel free to ask any question or add input.
again thanks

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Blues Creek Guitars Inc
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http://www.bluescreekguitars.com


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PostPosted: Tue Feb 19, 2013 12:27 pm 
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tippie53 wrote:
An update
No one will know who made the samples or the glue used on the samples until the study is completed. If anyone would like to add some input please feel free to ask any question or add input.
again thanks

You may have already considered this, but if different people are going to make samples, it might be a good idea to have them each make multiple samples, with each of the glues. That way, you can help eliminate the factor of how different people may do things slightly differently?


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PostPosted: Tue Feb 19, 2013 1:56 pm 
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Location: Hegins, Pa
that has been covered. There will be multiple samples . I can say that I have seen a number of guitars in the shop for repair because the tite bond did allow the bridge to move forward , This is called Creep. I stopped using tite bond on bridges a few years ago in favor of the fish glue.
I know some people won't admit that this happens but it does.

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John Hall
Blues Creek Guitars Inc
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http://www.bluescreekguitars.com


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PostPosted: Tue Feb 19, 2013 2:14 pm 
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tippie53 wrote:
that has been covered. There will be multiple samples . I can say that I have seen a number of guitars in the shop for repair because the tite bond did allow the bridge to move forward.

Do you ever measure how far it has moved forward? This would be interesting to know.
Since different builders allow for a variance on the scale length for intonation (usually around.100"?) I would think that the creep would have to be significant to eliminate variations in this allowance to not be a factor?


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PostPosted: Tue Feb 19, 2013 9:07 pm 
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Location: Arkansas
I should glue a bridge sized piece of wood to a spruce top with Titebond and draw a black line behind the bridge with a felt tip marker. Then hang it up in my shop with 180lb of weight hanging from the bridge and let it go through the heat of summer and cool of winter and see how much it moves in 2 years.

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PostPosted: Tue Feb 19, 2013 9:44 pm 
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Most of the affected ones were about 5 yrs or older. I agree that environment may be a part of the equation. I have seen what appears to be about 3/32 movement.
It is possible that there is more than one reason for this to happen. You can actually see the finish on the top having damage from this happening on severe cases.

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Blues Creek Guitars Inc
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http://www.bluescreekguitars.com


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PostPosted: Fri Mar 08, 2013 3:18 am 
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Any progress to report?


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PostPosted: Fri Mar 08, 2013 7:55 am 
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Location: Hegins, Pa
We have the base sample set up and are making the jig to make the samples
also there is a base made to hold the samples for testing.
we will be using a few different samples. Then Brian will test them. The samples Brian will get will be blind . He won't know who made them or the glue used.
The samples will be tested. Both in the green state and again after being vibrate to also see if they " Warm up". Then the end results will be retested in the university and the data correlated.
As of now we won't be telling much more than this but all samples we be sistered sets so that the sample pieces will be as similar as possible.
Thanks again for the interest

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John Hall
Blues Creek Guitars Inc
Authorized CF Martin Repair Center
Board of Directors of Association of Stringed Instrument Artisans
http://www.bluescreekguitars.com


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PostPosted: Sat Apr 13, 2013 2:01 pm 
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John: I will never admit to my bridges moving because I have never seen it happen. I have guitars that go back about 25 to 30 years with no evidence of this occurring. There has to be something going on independent of the glue, ie over heating or defective glue etc. And I am not saying this to be contrary and also am not saying that this cannot happen......................it has never happened to me. Good luck in the scientific study and am looking forward to results.
Tom

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