Hi Kellie, I’m not a bigtime caster, but had a couple thoughts after
reading your question.
The first question that comes to mind is whether there is any
discernible change in your spruing? Are you using sprue wax of a
different gauge than in the past, or have you changed the approach you
use in attaching them?
Another idea would be to attach fine vent sprues from the model back
down to the base of the flask before investing. Not to the button,
but to the base that the flask is resting on. This will give the
gasses trapped in the cavity an easier way to escape, minimizing the
build up of pressure in the mold. I haven’t normally found a need to
do this, but have a mentor who swears by it.
Hope this helps… I’m sure you will get a number of responses with
good things to think about!
Sebaste Studio and
Carolina Artisans’ Gallery
Charlotte, NC (USA)