C.F. Martin -- Penn State joint Glue Study - no such thing!

[ken cierp]

I continually get PM’s and emails asking for information about this alleged study / document which no one can find any mention by searching the Internet. So I recently contacted Dick Boak over at the Martin factory. His immediate response was that he never heard about it (he’s been there for at least 35 years) but he would check. He in turn contacted those in the engineering department and they made contacts with the Head of Structural Acoustics at PSU. Dick’s last Email simply said

”I checked and we are not doing a glue study with Penn State. Not sure where the disconnect is.”

[TonyinNYC]

But I read it on the internet, so it must be true!!

Thanks for the info Ken. As Mark Twain once said, "Just because you read it on the internet, that does not mean it is true."
Or was it Abraham Lincoln? Ghandi? I forget...I have to go look it up.

[Tim Benware]

But I read it on the internet, so it must be true!!

Thanks for the info Ken. As Mark Twain once said, "Just because you read it on the internet, that does not mean it is true."
Or was it Abraham Lincoln? Ghandi? I forget...I have to go look it up.

No, I said that Tony - I think I posted it on my Facebook page somewhere. I don't know why Twain keeps getting credit for it!

[TonyinNYC]

But I read it on the internet, so it must be true!!

Thanks for the info Ken. As Mark Twain once said, "Just because you read it on the internet, that does not mean it is true."
Or was it Abraham Lincoln? Ghandi? I forget...I have to go look it up.

No, I said that Tony - I think I posted it on my Facebook page somewhere. I don't know why Twain keeps getting credit for it!

I apologize Tim. It seems like people can just make up anything and say it online these days. Is there no truth out there at all?

[Trevor Gore]

When I was writing "the book", I checked to see if there was much by way of academic papers on testing of the acoustical properties of glues. Bottom line, I couldn't find anything. Nothing at all. Separately, I also asked on another forum whether anyone else had come across such a publication. Again, nothing. So if there is anything out there, it's hiding real well.

My conclusions re: various glues are that how you use it is perhaps more important than the glue itself. I have found that instruments built by student builders are rarely as good acoustically (yes, subjective I know) as those built by those experienced at the craft. So what is the difference when the tools, techniques and woods used are essentially the same? It seems to me that the most significant differences are the quality of fit of the glue joints and the speed of assembly. Closely fitting joints and rapid application of clamps seems to result in a better outcome, presumably because the glue line is thinner and more contiguous (here routinely using Titebond or epoxy/CF on tops). Successful HHG glue joints require well fitted woodwork, speed and experience to execute successfully and I would venture to suggest that it is the quality of the assembly rather than the quality of the glue that is largely responsible for any differences.

For those interested in the strength of glued joints, some interesting info here.

FWIW, I have used a couple of different brands of polyurethane glue, the Titebond version and a Sika product, but not Gorilla. The Titebond sets up fast and fizzes a lot; the Sika does not fizz as much and sets up slower. Both are pretty average products, similar, it seems, to the Gorilla glue. Fortunately, I was not using the stuff on guitars, but switched to Titebond original, which was much stronger with a faster set up and gave better results for that project.

[Dave Bagwill]

Trevor, do you have any experience with or anecdotal evidence about the use of fish glue?

[Trevor Gore]

Trevor, do you have any experience with or anecdotal evidence about the use of fish glue?

Sorry, no personal experience. Anecdotal stories are about fast tack, longer working time, long setting time and susceptibility to failure at high humidity, low temp.