Hi Syd, I can think of following situations that could result in the
problem you describe:
1) The holes in your crucible and investmentflask are not aligned
2) The passage between flask and crucible is blocked
3) Too much silver in the crucible. Remember: the weight of the
wax-tree times 10, plus 20 grams for the button.
4) Your wax tree-trunk too thin.
5) Flasktemperature too high, especially if you are casting big
6) Flasktemperature too low, if you are casting small items with
fine details (filigran).
7) Inadequate burnout.
8) Centrifugal force incorrectly adjusted.
Hope this will help.
INSULA BURGUNDI MARE BALTICUM