Strange thing happened with Fish glue on bridge.

Fred Tellier · **Posted:** Sat Oct 27, 2012 11:17 am

I was at a Michigan Fingerstyle society open mike at Bluefish music and one of my almost 2 year old guitars was there and I noticed the bridge was lifting. I took it home to do a repair and when I pulled the strings the bridge was already detached with only the bridge pins holding it in place. It was glued with Fish glue and the glue had totally detached from the top and the glue on the ebony bridge was slightly tacky.

My thoughts are hot car, bad glue, or maybe I did not let the naphtha I cleaned the bridge patch area completely dry. I did a test with spruce and ebony with the spruce damp with naphtha and destroyed the spruce getting it off after 24 hours.

Any ideas on what might have happened to cause this.

Fred

Alexandru Marian · **Posted:** Sat Oct 27, 2012 11:53 am

If your finger is moist (skin usually is a bit) fish will feel slightly sticky even if fully cured, it is normal. Looks like for some reason it didn't adhere and penetrate the spruce well enough. I'm afraid I don't have naphta experience, i glue my bridges on the white and vigorously scrape the spruce and bridge with a fresly razor sharpened plane blade. I brush the glue on both surfaces and don't rush positioning and clamping it, this allows it to soak in the grain for a bit before the bulk of the glue gets squeezed out by the clamps. My oldest fish bridge is 5 y and all 22 or so I glued (including a few repairs) are holding so far. But recently I switched to hide glue for this and it is much easier than I thought.

Fred Tellier · **Posted:** Sat Oct 27, 2012 12:12 pm

Quote:

If your finger is moist (skin usually is a bit) fish will feel slightly sticky even if fully cured, it is normal. Looks like for some reason it didn't adhere and penetrate the spruce well enough.

I am aware of the moist finger thing, the fish was soft when scraped off. I have used both fish and hide for bridges and the oldest is almost 5 years, this was something that happened on this particular bridge and has not happened before or since. I now will test my fish glue once in a while though what I used was quite fresh.

Fred

Alexandru Marian · **Posted:** Sat Oct 27, 2012 12:17 pm

Strange, I kind of doubt it was the glue. I found a bit on the bottom of an old bottle, probably sat untouched for 3 years, and when tested it worked fine. Rumor is it is safer to shake the bottle before each use.

nyazzip · **Posted:** Sat Oct 27, 2012 1:35 pm

http://www.youtube.com/watch?v=6S9yZ1l40tc

woody b · **Posted:** Sat Oct 27, 2012 2:58 pm

The only time I use fish glue is for binding, but I believe JJ had problems once which were solved by stirring the glue occasionally.

Michael.N. · **Posted:** Sat Oct 27, 2012 3:14 pm

Maybe Naptha had an effect but the stuff usually flashes off reasonably quickly. I've used Fish glue without stirring it, even though it has been sat on a shelf for weeks - I've never had a bad joint with it. At least not that I know of.
Having said that you may as well stir it, can't possibly do any harm.

WaddyThomson · **Posted:** Sat Oct 27, 2012 5:40 pm

Norland recommends stirring before using, always. Some batches of FG settle out a bit, and it's more reliable if you stir it.

Fred Tellier · **Posted:** Sat Oct 27, 2012 9:31 pm

I am not blaming the glue as I use it all the time, but I am trying to figure out what went wrong. I always clean the bridge and the top area with naphtha . The glue stayed with the bridge and came away from the spruce. I did a test joint with naphtha dampened spruce and it still held great. I think the guitar got hot but the owner says no. The funny thing is is happened quite suddenly after 1 1/2 years and was completely loose from the top.

Mark Fogleman · **Posted:** Sat Oct 27, 2012 11:42 pm

Fish glue is heat resistant to +500F. Failure has to be related to something else. According to Norland, clamp time should be at least 12 hours which is much longer than I use w/other glues.

Dave White · **Posted:** Sun Oct 28, 2012 8:11 am

Fred,

I assume that you've explored the humidity conditions that the guitar has been exposed to. Heat on it's own usually doesn't release fish glue but one double necked lap slide instrument I made for my daughter literally unzipped itself. The conditions were extreme and the exposure to very high humidity levels was over a period of months but it did pretty much as you described. You can read more about it here.

Fred Tellier · **Posted:** Sun Oct 28, 2012 9:09 am

I was with the owner yesterday and we had a long talk about the guitar and he could add no clues. It is back together and he is happy so I guess all ended well. I still wish I could figure out what caused it but probably never will.

Fred

Alexandru Marian · **Posted:** Sun Oct 28, 2012 10:56 am

Dave, would you please paste that story here? I don't have an account there and I guess many others as well.

Dave White · **Posted:** Sun Oct 28, 2012 11:55 am

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."

Alexandru Marian · **Posted:** Sun Oct 28, 2012 12:01 pm

Thanks! This is not putting me off fish glue either. The environment was extreme and I wonder what would have happened with hide glue? Assuming the joints would have held, the wood might have cracked from over bellying? I once measured the shrinkage of a rosewood half back from wet state to usable dry: 5mm or so!

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