Hide glue yes, same thing no
smieglitz said:
Is the woodworking hide glue the same thing as an oil painters' canvas glue sizing? Photographic ossein sizing?
Same family, diffierent stuff. Historically and still used but now not exclusively, the glue you are referring to is "rabbit skin" glue. Smells like it to when you warm it prior to mixing in the calcium carbonate filler.
It has less strength due to many factors. It does have to be more flexible and this is reflected in the ultimate strength.
As an aside if you are using hot hide glue of any sort and the odour gets to you neighbours or loved ones, try adding a very small drop of oil of cloves. It will not only mask the odour to some degree but is a preservative as hot glue will eventually "go off" and begin walking away on you. If you hale from a middle east background you accomplish much the same but you would use garlic. Probably not the thing to make vampire caskets from.
Liquid hide glues have amongst other things a preservative. By the odour I have always suspected formalin or something similar. Unless thinned out and left out uncovered I have never had any cold liquid hide glue go off.
If you warm and sometimes lightly thin the hide glues you can actually immerse decayed and rot deteriorated wood in a pot of it. Once it has absorbed the glue and cured, it has been consolidated to a great degree. Not for anything structural but it works on classic furniture where you need to preserve. Of course you can't do this with any wood you can see through parts for that we do other things.
You are right to be wary of metal pins of substantial circumference in wood. Especially if the wood is not sealed. Note, use of substantial circumference descriptor. Wood, cycling through humidity changes, and meeting a noncompressible material (the metal peg) will change its hole size due to a phenomenon known as "compression set-tension hold". However, if the pin is narrow it seems to suffer less ie. nails. However, wooden pegs, dowels, tree-nails, trennels, whatever, actually hold better, longer, and more sure. Having said that copper and other metal pins have been used for hundreds of years for decorative purposes.
Sorry to have strayed away from hide glue and into the pin discussion.
Regards
Mark MacKenzie