MIMF

Generally speaking when we talk about hot animal glues we say "hhg" as in hot hide glue but which do you actually use: hide glue or bone glue? By some accounts bone glue produces a harder, less flexible joint than hide glue. Does your supplier even state explicitly whether it is bone or hide?

Last time I ordered glue I got equal quantities of each. My new order is just for bone glue. No idea what the gram values are.

I use different glues for different applications. HHG for headstock scarf joint, dovetail joint, braces, bridge plates and bridges. Titebond for neck and tail blocks, top and bottom plates. CA for inlay, binding and purfling. HG comes from Cow and Pig hides. Bone glue is not commonly used in the US. What applications are you using it for?

192g high clarity for structural stuff and 315g for bridge.

Fish glue!

Hot hide glue dries hard and crispy. I can't imagine how another glue could be harder or less flexible unless it's like glass. The 192g HHG is stronger than the wood it holds, so why get higher gram strength? The higher the g the quicker it gels (less open time).

I use 192g hide glue for most things. I've never tried bone glue, but in the old days, I've heard it had a reputation for being more smelly. Where do you order your glue from?

I get both hide and bone glue from "dictum" dot de here in Germany. They supply hide, bone, "rabbit skin**" and fish glue. You can 250g upwards. I buy kg bags. I have used both hide and bone glues from this supplier. Bone glue definitely has a stronger smell. I can't really say I see much difference between the two for my purposes. Bone glue is a bit cheaper but it is pretty cheap anyway.

** actually hare. But the poor old hare is often translated from German to English as rabbit. The Easter Bunny in English is an Easter Hare in German.

Michael Lewis wrote:Hot hide glue dries hard and crispy. I can't imagine how another glue could be harder or less flexible unless it's like glass. The 192g HHG is stronger than the wood it holds, so why get higher gram strength? The higher the g the quicker it gels (less open time).

I too use the 325 HG on bridges based on the recommendation from Mr. Thorndal at Bjorn Industries a while back but used regular 192g from Behlens prior. Gelling is not an issue if you prewarm the bottom of the bridge and the footprint on the top with a hair dryer. You have more than enough time if you mask precisely and not worry about squeeze out until the clamps are ready to tighten.

The grip of most wood glues happens on a cellular/chemical level between two wood sufaces. Hide glue is a terrible gap filler and shatters/cracks like glass would. So any gaps filled w/hg are not dependable in a high shear tension joint.

Fish dries as hard and crispy as hide...just not nearly as moisture resistant once dry, so I don't use it where it's not well sealed with finish or by the nature of the joint. Also more of a PITA to heat release, so not something I use for joints that might be ones that get opened for major repairs. Not suitable for dovetails, etc., but great for binding (I glue in purfs with CA, then bind with fish on complex schemes).

Higher gram strengths of hide gel at higher temps...but also are stronger, gives better gap filling performance (when it's one of those days), and sets up to full strength much faster than mid-strength hide grades like 156g or 192g. The biggest difference is that bridges and other highly stressed components are ready for loading in hours instead of days. Glued on a few hundred bridges with both 192g (before I knew better) and 315g... 192g will release if abused (dried out or repeatedly heat and RH cycled) or if not allowed to dry for an extended period (24-36 hours). 315g will not release without very intentional efforts, and it's ready to load after 8 hours, versus 24-36 for 156g or 192g. And as a pro, being able to string up a guitar 8 hours after the bridge goes on beats waiting another day. Time are moneys.

I know my joinery, glue prep, and glue are perfect , but there may come a day where I have to worry about imperfect joints, contamination on the glue surfaces, and a slightly aged batch of glue...reality-based luthiery suggests I take advantage where possible.

The seems to be a big divide between Europe and the US in matters pertaining to animal glue. Reading here, it seems that the US has just hide glue but with quantative descriptions of glue strength whereas has Europe (or at least Germany) has a variety of animal glues available (bone, hide, rabbit and fish) but zero technical description of the characteristics. Dictum, the German supplier I use describes hide glue as "flexible" and bone glue as "hard" whereas rabbit skin is describes as "very elastic" but nosing of "gram" values for any.

That's the guidance I see...bone for rigidity, rabbet for elasticity, and then the various fish glues (isenglas, etc.) for longer open times without adding urea. Seems like violin builders have the more unique set of requirements (periodic disassembly, etc.), so hot hide seems to be the go-to animal glue, with fish as either a substitute or as a special purpose glue. Not sure I'd want more rigidity than I see in 315g.

I also use different glues for different purpose and according to materials.

I've read this thread through with great interest. Some of you know that I am embarking on my first acoustic guitar build soon.
My question on this topic is about availability of hide glue.

The only place I have found it here in Canada so far, is at Lee Valley. I will say I have only begun to look.
They advertise two different kinds of glue. Both come in dry form (flakes) in a bag.
1. Granular Hide Glue. 260 g strength. Short open time.
2. Pearl Hide Glue. No rating provided. Longer open time.

Can someone tell me which applications would take the different glue?

1. Body Assembly?
a. Jointing back, front, gluing top and back to sides?
b. Braces, and reinforcing?

2. Neck assembly? Gluing fret board to neck and body top?

Granular Hide Glue is what you want.

Gordon, I bought from LeeValley the first time I used HHG, then found a vendor on ebay for Milligan & Higgins 192g strength high clarity. Only thing I would use the LeeValley stuff for now is glueing bridges.

Bob

Gordon Bellerose wrote:
1. Granular Hide Glue. 260 g strength. Short open time.
2. Pearl Hide Glue. No rating provided. Longer open time.

Can someone tell me which applications would take the different glue?

1. Body Assembly?
a. Jointing back, front, gluing top and back to sides?
b. Braces, and reinforcing?

2. Neck assembly? Gluing fret board to neck and body top?

Not the answer you're requesting but my advice is to use fresh Titebond Original (red cap) or LMI yellow glue on everything except the bridge. There is no significant benefit (sonic or strength) in using HHG over TB red cap in the less stressed parts of the guitar. Use the strongest HHG on the bridge. Practice clamping the bridge to the top until you can do it in <30 seconds and preheat the bridge to delay gelling once you're ready.

192g high clarity for everything except the bridge, which benefits from 315g. If you heat the bridge to 130-140, you can take 5-10 minutes to get things clamped and still be waiting for 315g to cool enough to gel. Linings? Apply glue, heat with heat gun, hold lining in place and let it gel...tape, then move on. Linings are similar...hit the lining with hot water, coat with glue, clamp, then hit with heat gun to remelt...wait for squeeze out to stop and clean up. Hide is pretty easy with some basic tools (heat gun and a plate warmer for components). Takes a couple guitars to develop enough speed to forego the gun for braces etc.

Fish is a partial substitute - longer clamping time and really wants more even clamping pressure, but the open time is nice for bindings. Some folks like it for everything, but I use it only where the entire joint is well sealed against high humidity.

Titebond...for your first couple guitars, why not? If you end up repairing, you'll quickly come to view Titebond as a contaminant versus a glue, but chances are the first couple guitars will be learning experiences versus masterworks, so the drawbacks to AR/PVA - lack of repairability, poor clean-up, hot creep, etc. - are more than balanced out by it's virtues: it's cheap, easy to find, and gives predictable performance for novice woodworkers without picky joint prep or good clamping technique. Pick your battles - one less new skill to master to get through your first few guitars might be a good trade for some down-stream frustration on a lifting bridge.

what Todd said.

Oops...that was 'Binding? Apply glue, ..." rather than linings...both are easy to do with hide with the right technique and the ability to apply a little spot heat.