Making liquid hide glue.

[ken hatch]

I've just finished making a small pot of liquid hide glue. I'm using Don Williams' method of two parts hide glue pearls to three parts of water with one part of salt. Cook for two hours then refrigerate over night. After the over night in the refrigerator cook two more hours to finish. One of the advantages of his method is using table salt instead of urea. With salt there is no shelf life limit, we will see if that is true. I've a test piece glued and in the clamps, report on the joint tomorrow.

ken

[Bob Glenn]

Looking forward to your report. I go back and forth on liquid and hot hide glue, depending on the joint. I've had some liquid hide failures, but chalked it up to old glue. Bob

[ken hatch]

Looking forward to your report. I go back and forth on liquid and hot hide glue, depending on the joint. I've had some liquid hide failures, but chalked it up to old glue. Bob

Bob,

Pretty much the same here. That's one of the reasons I'm trying this method with a claim of no expiration date because of the salt. That part I will not know for sure until a year or so down the road but it is easy to make and by making it I do not have to worry about running out.

ken

[Mike Cornwall]

I didn’t get good results using salt but I didn’t use the method you describe.

[ken hatch]

I didn’t get good results using salt but I didn’t use the method you describe.

Mike,

I'll see what happens to my test joint in a few hours. It may not be definitive because the two pieces of wood were only ~6 or 7mm thick. I figure if that thin a joint holds then the glue will work on almost anything.

ken

[chris carter]

I've used salt to allow more open time before with good results, but I only added a little salt for a little time. I will probably try to make some liquid hide glue when my titebond liquid hide glue runs out. I find it very convenient for quick little things where I need a tiny bit of glue and don't want to go through the whole heating process - or things where I need a lot of time. So I'm super curious to hear the results of your liquid hide glue test.

I found this to be an absolutely wonderful resource for hide glue, including formulas for hide glue modifications. I printed the whole thing starting at page 9 and keep it next to my bag of dry hide glue.
https://emgw.org/resources/Documents/Meeting%20Presentations/2016%2005%20Hide%20Glue%20in%20the%20Modern%20Work shop/Hide%20Glue%20EMGW%20Presetation%20Handout.pdf

[bill epstein]

Bob,

Pretty much the same here. That's one of the reasons I'm trying this method with a claim of no expiration date because of the salt. That part I will not know for sure until a year or so down the road but it is easy to make and by making it I do not have to worry about running out.

ken

I have an open, 1/2 full container of Behlen Pearls that's easily 20 years old. Don't ask.

If you want a real test of shelf life, it's yours.:D

[Warren Mickley]

Salt is hygroscopic; it absorbs water from the air and it tends to retard evaporation when it is dissolved in water. It also retards moisture transfer from the glue into the wood, which slows drying.

A Winterthur study found that liquid hide glue was considerably weaker when exposed to humidity over 80%. They concluded it was fine for furniture since furniture would never be exposed to high humidity. I think the salt would encourage the glue to pick up moisture from the air in times of extreme humidity.

[Charles Guest]

Excerpts from the Winterthur study which can be found in its entirety here: http://www.wag-aic.org/1990/WAG_90_buck.pdf

(http://www.wag-aic.org/1990/WAG_90_buck.pdf)I wouldn't quit using liquid hide glue based on this study at all unless you plan to store your fine furniture in an un-airconditioned shed during the summer and bring it into the house in the dead of winter when the air is driest and do it repeatedly year in and year out. If the inside of your home regularly reaches 150*F and 80% relative humidity then epoxy would be a better choice than any kind of hide glue product.

"The resulting analysis showed that the most overwhelming factor affecting glue strength in this test was environment. (relative humidity and heat), rather than glue type. There is a statistically significant difference between the environmental conditions, with a p value of less than 0.01 – in other words, the probability of obtaining these results through chance alone is less than 1%. (15). The high RH condition of 84% and the high temperature of 150 degrees F. were shown to significant reduce glue strength as measured in the shear test. The type of glue used is comparatively less significant, in part because of the interaction with the environment, although hot hide glue was shown to be less sensitive to environmental changes than liquid hide glue with a p value of less than of 0.01 (15)."

"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."

The testing also apparently found, interestingly, hot hide glue to be less strong though rightly points out this could be an advantage in certain circumstances:

"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."

[Rob Young]

Salt is hygroscopic; it absorbs water from the air and it tends to retard evaporation when it is dissolved in water. It also retards moisture transfer from the glue into the wood, which slows drying.

A Winterthur study found that liquid hide glue was considerably weaker when exposed to humidity over 80%. They concluded it was fine for furniture since furniture would never be exposed to high humidity. I think the salt would encourage the glue to pick up moisture from the air in times of extreme humidity.

Don has a pretty nice blog going and he does answer questions about his work. I keep meaning to ask for follow up since the recipe mentioned above was from a few years ago. In fact, I think I'll pop over there and do it now.

Edit to add: contact form seems broken on his blog page, could be any number of issues. But dug through old emails and found address from a long time ago, hoping it is still active.

[ken hatch]

First test of the liquid hide glue failed. The joint broke cleanly on the glue line after setting for 20/24 hours. It took heavy pressure to fail the joint but it was the glue that failed not the wood. See photos:

431018

431019

Next I'll clean the edges and use hot hide glue and see if the results are different.

ken

[Christopher Charles]

Hi Ken,

Isn't one of the advantages of wood glue that it fails predictably (but is perfectly strong under normal use?)

Nice gennou. Hiroki?

[Charles Guest]

First test of the liquid hide glue failed. The joint broke cleanly on the glue line after setting for 20/24 hours. It took heavy pressure to fail the joint but it was the glue that failed not the wood. See photos:

431018

431019

Next I'll clean the edges and use hot hide glue and see if the results are different.

ken

Hyperbole aside about the ridiculous atmospheric conditions it takes to make a glue fail, and under other circumstances that cause the sad event, at the end of the day you'd rather the glue fail and take as little wood as possible. I'd consider your test an absolute success. Bottle it and send me some. The glue needs to cut loose before the wood does.

I noticed that Elmer's has advertised that it had made its white glue stronger and I just screamed inside "NOOOO." The last thing it needed to be was stronger.

[Robert LaPlaca]

I use hide glue for the furniture I build, depending on the situation, I will use straight hide, other times I use either salt or urea to suppress the gel time for more open time. I usually use no more than 10% by weight of hide pearls for the suppression, so the glue is not liquid at room temperature and needs to be heated to be liquid, maybe I get 5 to 7 minutes of open, depending on the ambient temperature. I use 192 gram high purity hide from Bjorn.

If you are using salt, I would be using kosher or pickling, these salts don’t have any anti caking or iodine added to the salt.

Hide glue produces a pretty rigid glue line, like really rigid, another way of saying brittle. I would agree I would rather have a glue line fracture that is plenty strong, taking some fibers with it, than ripping the wood apart with a catastrophic failure.

[chris carter]

First test of the liquid hide glue failed. The joint broke cleanly on the glue line after setting for 20/24 hours. It took heavy pressure to fail the joint but it was the glue that failed not the wood. See photos:

Next I'll clean the edges and use hot hide glue and see if the results are different.

ken

It's possible 20hrs wasn't long enough. I remember gluing up some panels for the top of a desk and I used Titebond liquid hide glue. I came back the next day close to the same time and there was a tiny bead of squeeze out that was still soft enough to easily dent with my fingernail. I freaked out and thought my glue had gone bad. I waited a second 24 hours and it was solid. That's my one gripe with liquid hide glue is that sometimes, depending upon the joint (and temp/humidity apparently!!!) it can just take FOREVER.

[ken hatch]

Hi Ken,

Isn't one of the advantages of wood glue that it fails predictably (but is perfectly strong under normal use?)

Nice gennou. Hiroki?

Chris,

I expect the you are correct in where you would like the failure to happen. I also expect it varies with different woods. More tests to come.

The gennou is an old one from Japan Tools before it became "WoodCraft". I don't remember it being expensive but it does work well and I've never felt the need to replace.

ken

[ken hatch]

IAW my very unscientific test the hot hide glue makes a stronger bond. Again using my un-calibrated hands the break took about the same force with with either glue the difference the liquid broke on the glue line, the hot broke wood. Take your pick, my opinion is the liquid bond is strong enough for most applications.

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ken