I am having an odd problem with black pitch. Normally, the pitch is
relatively hard once melted into a vessel, and has minimal
compression when hammered. However, a student put pitch in her
vessel, and as she hammered it started gradually squeezing out. It is
soft and a bit tacky--I could easily stick my fingernail into it and
rip off a piece. I thought that there could have been a contaminant
in the vessel, so we melted the pitch out, cleaned the piece up, and
put brand new pitch in. The same problem is occurring.
I have no idea what to think. I have used pitch numerous times in
the past, both in my own work and with students, and I have never
seen this. The pitch seems normal before we start--we have to break
it into pieces with a hammer. Any thoughts on what is happening?
Thanks in advance.