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I have recently fallen in love with Fish Glue -- if you prep your joints correctly, this stuff is just wonderful. However, I came across an unusual feature of this glue that I wanted to share.

I was doing some soundboard inlay/purfling treatment and decided to use fish glue to inlay a 0.030" thick strip of ebony. I normally will seal with shellac and use CA glue for my binding/purfling. I did the exact same thing on 2 different guitars and the fish glue used to cut across the grain lines soaked into the soundboard and slightly discolored the top. It did not soak into the grain when running with the grain. I do know what I am doing and the facts are simply that the long open times of fish glue allow it to soak into end grain more than a quicker drying glue. Both of these tops were German tops but I think that is an insignificant point. The discoloration extended about 0.030" into the top and changed the texture and color of the wood slightly but noticeably.

It was an easy fix -- just cleared out the line and went with a wider inlay. Nevertheless, I thought folks who use it for binding and purfling might want to be aware of this and perhaps seal the endgrain with shellac. I think the fish glue will adhere to shellac but I am going to test it anyway.

Just thought this might be useful information and wanted to share.

Yes I noticed this, fortunately the discoloration is hard to notice after applying the finish (at least in my case, dark shellac) The real problem is not the discoloration, but the joint starvation! The end grain needs to be sealed, but not with shellac, as this will make an even weaker bond. Simply paint the endgrain with a bit of fish glue using a stick. Work it well as not to leave thick spots or blobs that will prevent the purfling to seat well. In 30 mins it is dry and you can fit and measure the purfling without issues.

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Build log

The inlay bleeding issue is even worse with HHG. A Black veneer purfling immediately next to end grain Spruce can really wick the dye into the end grain. The fix is very easy. Do what Alex. suggests, whether Fish or HHG. End of problem.

Michael, odd, I had been lucky with hide so far, bound 3 and had zero contamination, no glue or color.

Filippo, I've seen the contamination on 4 guitars before figuring out what to do. As I said, once finished it is very hard to see. It looks worse on low density or wide grain spruce.

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Build log

Thanks for the tip, Alexandru. I will try this and see if it helps. I will also test how fish glue bonds with shellac as well.

Well it might depend on what you are using for purfling. There is certainly a little dye contamination with the Veneer that I use. I virtually always use Black as the first line next to Spruce. I'm fairly sure the veneer is spirit based dye, sourced from various suppliers over the years. Anyway, sizing the end grain and allowing it to dry is the cure.

Simon, I use shellac on the top, bridge, FB etc to protect them when gluing them. There is minimal adhesion and I can easily peel off the dried glue from the shellacked surface. Sure sometime it can "cut" through it and become hard to remove, but only rarely.

Michael, I used black too, from madinter. Really cheap stuff, good quality, I swear not a bit of color leaked.

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Build log

I'm another one who's very much liking fish glue for bindings, and have not had any issues. Any purfling bleeding, no matter what adhesive or glue was used, is a sign of bad/cheap purflings.

As for the glue itself seeping into the wood and changing the appearance, that's the beauty of fish or HHG. They are protein-based, just like the wood itself, and will accept stain or finish(though I can't say for sure with water based crap, since that just sits on the wood surface...) just like the wood. So just continue-on with the process, and once you begin to apply finish, it will all be fine. That's exactly the reason -why- I love fish glue for binding, especially with a mahogany back and sides(which I leave natural; no stain or dye); if any glue 'fingerprints' get left behind, they won't stand out when you apply the finish. PVA and CA glues, bloody-well will!

I've been using fish glue for binding for a few years now and love it. It is so much nicer to scrape and sand then the yellow glue I used in the past. I've never had any issue with bleeding that was noticeable under finish.

Josh

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Josh House

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Just a quick comment. This staining would have shown up under finish. These tops were relatively light/white soundboards but my pre-finish prep is to wipe everything with mineral spirits -- and these areas were extremely visible. I wouldn't have bothered to make a post if they would have disappeared under a finish. I often use Smith's epoxy (long open time) to glue in rosette purflings and sometimes the edges of the soundboard right against the purfling will look darker but this does go away under a finish. In other words, I am very familiar with how the finish process can change the appearance of these kinds of things. This may just be a weird accurrence but it did happen for me twice -- and so, I am taking Alexandru's advice and sizing the grain beforehand.

It has also been my experience that fish glue CAN be absorbed through end grain of spruce because of the capillary action, enough for the stains to still be somewhat visible under a nitro finish. I've seen this happen at least once, long time ago, on a Italian spruce top. Anyways, sealing these areas with a thin layer of glue, as has been mentioned, works well. I now do that as a matter of course, at least when I remember...

BTW, this is a technique that is well known in the violin world, where it is common practice to seal the end grain of the end and corner blocks, usually willow or spruce, with hot hide glue, before the top and back is glued on. Unlike guitars, the grain of the blocks on violins usually run the opposite direction of the sides, so the sealing is done to avoid glue starvation on these points.

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Rian Gitar og Mandolin

I am sold on Fish glue and use it for many processes in building. I don't use anything but Duco on rosettes , wood or plastic. I don't use dyed wood bindings so I don't see any issues after 30 guitars and 4 years of using it.

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John Hall
blues creek guitars
Authorized CF Martin Repair
Co President of ASIA
You Don't know what you don't know until you know it

I always seal my rosette and purfling channels with a few coats of brushed on vinyl sealer then wick in thin CA glue and never have any color bleed issues , even with black fiber purflings. I use good ol Titebond for wood binding and weldon 16 for plastic, call me old fashioned but I always get great results. I haven't actually used the Fish glue for anything yet, but it seems that a longer open time could be a benefit.

A gallon of Norland's fish glue arrived yesterday, so I guess I will be trying it out shortly. It made no sense to order a smaller quantity due to their $25 minimum order plus shipping costs. 2 quarts would be necessary to meet the minimum and would total $29.00. i think a gallon was a schosh over $30.00, so I went with that.

Thanks for all the informative posts.

James Burkett