Bill Mackin talks about problems with mold that forms on the hide glue
and wants to know how to get rid of it.  When I use hide glue, I heat
it up in a small double boiler (a baby food jar placed in a small
saucepan filled with water).  When I am finished with the glue for the
day I leave the cover off of the glue.  This allows the top surface of
the glue to dry and the mold doesn't seem to multiply as fast.

The next time I need to use the glue, which could be 1 day or even 2
weeks, I add a small amount of water to the glue and place the jar into
the hot water.  The glue is ready to use after about 1/2 hour.

I have also heard that putting the glue in the refrigerator also helps
but I haven't done this.

When mold forms, I do one of two things:

1) Before heating up the glue, run water on the top of the gelled glue
to wash off the mold.

2) If the mold is very bad and smells like an old dishrag, I throw the
glue away and start over with fresh glue.  Be sure to wash or replace
the glue container before making the new batch.  Your mold will only
come back sooner if the mold spores are still on the surfaces of the
glue pot.

Mixing the glue in small batches is not a real problem for me.  When
my baby food jar gets low on glue, I add the dry glue to the remaining
glue, add water to just cover the top of the dry glue, place the jar
in the hot water and wait about 15 min. I then stir the glue, add more
water to get the right consistency, and then wait another 15 minutes
before using the glue.  Waiting an additional 15 minutes is necessary
so the glue crystals can completely dissolve.

If the glue looks like it has tiny bumps in it, wait for a longer
period.  The final step is to remove any white stuff that seems to form
on the top of freshly made glue.

I have been told that the preferred way to prepare the glue is to start
with dry glue, add water so it covers the top of the crystals by about
1/8-inch of water and let it sit overnight.  The next day heat your
glue and then remove the white stuff that forms on the top.

Pete Knobloch
Tempe, Arizona, USA