Tuesday, April 4, 2017

Day 145: Here Fishy, Fishy

It's been quite a week at Tortuga Early Instruments Worldwide Headquarters. After looking at the hot hide glue seam in the soundboard for the better part of a week, I decided it simply could not stand. So, I chopped it off and reglued it using the trusty, old fish glue. All was going swimmingly well (pun intended) until I pulled the clamps off to discover the distal end (away from the keys) somehow came out of alignment so that one of the boards was higher than the other.

Rather than panic, I knew the glue was not completely set (heck, the open time for the fish glue is an hour), so I went ahead and, like my dear mother when I was a sick little monkey, provided a moist, hot towel and applied some pressure.

I left the it sit for about an hour and same back to find that it had realigned itself, so I went ahead and shot a little more glue in and reclamped it for the final push.

The next day, things looked pretty great.

I'm pleased with the joint and even more pleased with the ease of use and performance of the fish glue. Now, my beloved mentor, Owen Daly, tells me a story about receiving a clavichord for repairs some time back that was constructed with fish glue that had fallen completely apart. This is, of course, not good. On the other hand, Mark Roberts tells me about a fellow luthier who built a multitude of classical guitars over a 25-year career with instruments now living on every habitable continent on the planet in every conceivable environment and he has yet to receive one report of failure.

I rather enjoy the fish glue. Its open time is phenomenal, it cleans up nicely, and once set, it's hard as a rock, unless sufficient heat is applied. Owen explained to me that simply rubbing a fish glue joint between the thumb and forefinger will loosen the joint, but I've not found this to be the case. In fact, I've found that moisture will not cause a failure - I soaked a test joint in water overnight with no failure - and it takes quite a bit of heat from a heatgun to melt the glue to the point where I can pull the pieces apart. In a strength test, I applied forty pounds to a joint and the wood broke before the glue joint failed.

As you can imagine, I defer to Owen with regard to just about everything I do related to harpsichord building, yet I can't help but wonder if, like hide glue, there are different strengths of fish glue. I have no idea why the open time of the fish glue is so extensive and I plan to call the supplier to inquire about any chemical preparation they might be doing to the stuff, as well as ask them about strength over time, etc. I suspect there is more to the fish glue I'm using than meets the eye and I intend to get to the bottom of it very soon.

Until next time...

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