Dear MMD'ers, I was working on an article about some properties of hot
hide glue. Mr. van Eeken's question [991113 MMDigest], however, urges
me to post a part of the article now; it might be of some help to him.
A group of students in the Netherlands, coached by Mr. T. de Vries,
experimented with the properties of hide glue recently. One of the
questions was "Does hide glue still hold after heating?"
So they warmed hide glue, diluted one part glue to six parts water,
in a bath of boiling water "au bain Marie" for several hours, and then
tested the pulling strength by gluing two blocks of beech wood with a
known surface together and pulling apart the blocks after drying.
It turned out that the glue took more than eight hours to gel after six
hours of heating, and more than two days to gel after twelve hours
heating, so it seems to be possible to make a "cold hot hide glue".
This glue still held with the same strength as hot glue, greater than
six Newtons per square meter (6 N/sq. mm). Moreover, increasing the
"open time" made the seam even stronger: 6 N/sq. mm after two minutes,
nine N/sq. mm after six minutes, and over ten N/sq. mm after twelve
minutes! After fifteen minutes the cold hot hide glue started to gel
on wood (not in the glue pot).
It seems that Mr. van Eeken can glue his organ parts without using
any additives to his hide glue, only by using pre-warmed and cooled
down "cold hot hide glue".
With best regards from the Netherlands,
Hans van Oost