Alexandru Marian wrote:
Dave, would you please paste that story here? I don't have an account there and I guess many others as well.
Alex - it's easy enough to sign up there but here's the post - apologies to Fred for a slight hijack:
"Fish Glue - A Cautionary Tale
Or should that be a cautionary tail
I love collagen glues. I moved over to using hot-hide glue nearly five years ago and a couple of years ago when Colin kindly gave me some I started using fish glue too. I loved it and saw it as the compliment to hhg where time was an issue in setting up. I use it for binding, gluing on neck and tail blocks and gluing on linings amongst other things. It has provided great joints and took a lot of heat and moisture to take apart.
I’d heard tales of it letting go in very high humidity but Colin has some glued joints in his bathroom that have been there for years and are still glued. Well last year I got to see a different test situation. My daughter Martha loves acoustic lap slides – I made her one for her 21st birthday and then when she saw Paddy Burgin’s double necked one on Youtube I had to make her one of those too. Then she moved to the “flat from hell”. It was pretty much underground and the bathroom was installed in the middle of the flat area rather than on an outside wall. The extractor fan went into a pipe system that went to the outside wall via Martha’s bedroom. Well the pipes weren’t set up to obey the laws of gravity and water collected and vented into her room rather than outside. Plus the flat suffered from rising damp. After about ten months there, Martha was taking photos of mould and fungi growing on the kitchen walls, her flatmate’s vinly record collection that were sealed in cellophane were wrecked by damp and warping and one day I got a phone call from Martha in tears saying that the back edge of the top on Orthus (the double neck) was lifting. I told her not to worry and that everything in guitar making was fixable. I was having the engine replaced in my car so couldn’t get to her to pick up her single and double neck instruments until a few weeks later.
I think her room must have been at 100% humidity for months on end with warm air and moisture from the bathroom. All of her clothes had mould growing on them and stank and the wooden slats on her bed were warped. This is how Orthus looked:
The good news was that the top, back and sides had peeled cleanly away – as if the glue had released perfectly – and there were no cracks. In the waist area the binding on the back had come away from the body as the linings released and then had re-glued:
All of the top and back braces were sound (hot-hide glue) and the single necked instrument (hhg and Titebond) was sound. I think that the tension of two sets of strings on the double neck was enough to move things as the glue released. Initially I was hoping to just re-glue everything back in place but given some of the movements it soon became clear that I would have to re-bind and refinish the instrument once I had it back together. The bridge had lifted but the fingerboards hadn’t (these were glued with fish glue) and perversely they were the usual bugger to remove – again this points to the string tension being key.
The repair gave me lots of challenges – I had made it two off-set tail blocks as I didn’t have long enough sides and so nothing was straight to provide clamping pressure for gluing !! I got in contact with Bob C to see if he had any more Curly eucalyptus bindings that I had used and was glad to hear that he had and bought some. Then I checked the length and they were an inch shorter than the originals !! Colin came to the rescue again as he had some from the same original batch from Uncle Bob.
Here’s a few pictures of some of the repairs. Orthus is ladder braced and the lower bout behind the bridge had distorted a little more than I liked, so I took the opportunity of making a small X brace that I glued in using magnets and clamps:
Here’s the side getting glued back to the back/lining at the waist:
And here’s Orthus back together again and sounding as good as new (in fact better than new).
Now has this put me off using fish glue? Not at all – in fact the complexity of some of the repair joints meant that fish glue was the only choice for me. This test was an extreme one for a guitar’s environment. But I will go the extra mile now to find ways of using hhg for as many of the joints as possible."