hide glue, fish glue.. working time.

[sunburst]

...here is a Woodworking magazine article from 2011 on LHG ...

There it is again!!!

"A point to be made here is that these additives all reduce the strength of hide glue. But that is not a critical issue due to the fact that liquid hide glue, although slightly weaker than hot hide glue, is still stronger than the wood itself."

[David Houchens]

James, yes. I cut the slots with perfling cutters so the neck isn't a problem. Lets me hold the mandolin in a vise while I glue and tape the binding in. Gluing the back on in that shot.

[Bernie Daniel]

There it is again!!!

"A point to be made here is that these additives all reduce the strength of hide glue. But that is not a critical issue due to the fact that liquid hide glue, although slightly weaker than hot hide glue, is still stronger than the wood itself."

Yes again as you say that is not always true and it depends on the conditions (heat and humidity) but for this test at least conducted under standard room conditions (70 -72 degrees F and 35 - 45% relative humidity?) they have data to support the statement -- using pine as the test wood of course.

"To test the glues for failure, we assembled 10 sets of joints using Eastern white pine, five joints per glue. After a 24-hour period we placed the pieces with one edge resting 3⁄4″ above the bench, hammered the pieces until we achieved separation then examined each result for a specific type of failure.
What we found from our basic test was that 60 percent of the failures were in the wood, 30 percent involved partial wood failure and 10 percent were a complete glue-joint failure. What was interesting is that both liquid hide glues experienced identical results. The only difference was in the partial wood failures. More wood fibers were apparent on the Titebond assembly than on the joint glued with Old Brown glue".

So 90% of time under these conditions the wood failed or partially failed?

OTOH we are also glad that the bond can be broken without harming the wood when we need to do it.

[sunburst]

Sure, if you test in controlled, ideal conditions it's easy to get joints "stronger than the wood itself". I've done it with water.
Put some pieces of wood in the freezer and let them get cold. Clamp two of them together with cold water in between, put them back in the freezer and wait. After the "glue" "cures" (that is, the water freezes) try breaking the joint. It will break in the wood, not the "glue". That "proves" that water is "stronger than the wood itself". Of course, allow the pieces get out of their proper range of conditions and the joint looses strength, but that can be said for most glues.

Also, when we test glues we should test to failure under sheer, tension, and any other forces that the joint may be subjected to, under various conditions of temperature and humidity. It's a pretty good guess that we can find a situation where the glue is not stronger than the wood, otherwise there would be no glue joint failures.

[resophonic]

Thanks John and Wes. I would have never thought to look in a hobby or art supply store.

Scott

Garden centers carry Urea, much cheaper there than the hobby/art suppliers.

[Bernie Daniel]

Garden centers carry Urea, much cheaper there than the hobby/art suppliers.

Also if you believe the Woodworking article cited in post #25 you can get the same thing effect using table salt!