Thread: Franklin Liquid Hide Glue

The consensus in lutherie circles seems to be that it is good for glueing on your labels and not much else. The additives which are used impede strength too much.
I notive that Australian luthiers supplies now have liquid fish glue which seems to be better.

If youve got a hard on for animal glue then youll find the consensus amongst luthiers is that its better to make up the stuff fresh from granules rather than use the ready made product.

Learn to work with the real stuff. It's not difficult if you work quickly and have your gluing setups really ready to go. No going and looking for clamps after you spread the glue!

Many of us are storing HHG in 2 oz plastic bottles with dispenser tips. Put a few stainless steel bolts in the bottom of the bottle to act as weights and heat sinks, and then put the bottle in a heated glue pot with water at about 145 degrees F. Then dispensing the glue is no more difficult than working with ordinary carpenter's glue.

Check over at the Official Luthier's Forum for a lot about how to use the stuff. You can freeze the mixed glue when not using it.

Originally Posted by jeffhigh

The consensus in lutherie circles seems to be that it is good for glueing on your labels and not much else. The additives which are used impede strength too much.

There's a lot of lore surrounding animal glue additives; some of which is justified, but Franklin add ammonium thiocyanate and dicyandiamide which are not generally available to the average woodworker and have lab-tested their Liquid Hide Glue.

I've never tried LHG, but at 3,5900 PSI, it's on a par with most synthetic glues. Even the 'premium' glues are only 5-10% stronger, so I wonder why it's not more popular.

Frank ford over at www.frets.com loves his hide glue and has a lot of good articles about it. He doesn't like the pre-liquified stuff thou...

I just read a study conducted by Stamford University on the properties of commercial liquid hide glue and traditional hot hide glue in response to changes in relative humidity and temperature. This is their summation:

A result of interest to conservators is the difference in mean PSI between liquid hide glue at 50% RH and the mean PSI of the liquid hide glue blocks conditioned at extreme temperature and relative humidity. The liquid hide glue mean PSI of 4173 at 50% RH indicates a very strong glue bond, but the strength drops off sharply at 84% RH (1143 PSI) and 150 degrees F. (1403 PSI). While the standard deviations around these means are relatively large, these results still indicate that liquid hide glue lost more than two thirds of its strength under extreme environmental conditions.
In contrast, hot hide glue had a lower shear strength of 3640 PSI at 50% RH, which dropped down to 2636 PSI at 84% and 2357 at 150 degrees F. Thus, in this test, hot hide glue lost approximately one third of its strength under extreme conditions.

An intriguing comparison can be made for percent wood failure at 84% RH between the two hide glues. A 2% wood failure value at this high humidity indicate that the hide glue join tends to fail completely under shear pressure – a finding consistent with Franklin Industries’ caution not to use liquid hide glue if the object will be exposed to high RH conditions. The hot hide glue blocks tested had a 13.7% mean wood failure at 84% RH. The wood failure results in combination with the shear strength test indicate that marked glue degradation occurs at high RH, and that liquid hide glue is more greatly affected than hot hide glue.

Conclusion
The results of this testing reinforce the importance of maintaining a controlled environment for the display and storage of wood objects. The most critical factor in the strength and stability of the 20 liquid hide glue and 20 hot hide glue joins was the environment.

Based purely on strength characteristics this testing indicates that liquid hide glue is the glue of choice for repairing a join which will undergo significant stress, such as the structural join of a chair in regular use. But, more importantly, that decision must also take into consideration the environmental conditions. Under normal conditions of 50% RH and room temperature liquid hide glue provides the strongest bond. However, hot hide glue proved to be the more stable of the two glues under extreme conditions of high heat or high humidity, and thus would be the more desirable choice if fluctuating environmental conditions are anticipated.

It is also important to consider whether a very strong bond is desirable, especially if it is coupled with a higher percentage of possible glue failure. In instances where the glued area will not be subjected to excessive stress, the slightly lower strength, lower percentage wood failure hot hide glue is more appropriate.


So unless you live in the tropics or the Sahara, Liquid Hide Glue is actually an all-round better product!

I'm a dyed-in-the-wool hot animal glue woodworker, but I may just buy a small bottle of Liquid Hide Glue and give it a go.

The next question is; can LHG be refrigerated or frozen to extend it's shelf life, or will the additives have some ill affect?

That sounds to me like LHG would not be a good guitar glue. A guitar is under a fair bit of strain permanently when strung up. If there is any risk of humidity going up or low, the string tension would do the rest. I'm betting most places in the world would get at least a few days per year of high or low humidity.

Peter