As long as you are doing a single item in a tiny flask (dental ring),
it can be done easily. The secret to the process is that you use
phosphate bonded investment and not gypsum bonded investment.
Typically, these are dental investments.
The flask is placed in the oven, which has been pre-heated to the
soak temperature and burned out in one hour. The best investment I
have seen for this extremely fast burnout is the old Prevest
Accu-Fit, which is now available from R&R. There are now many
casters around the country using this process. You can use most
dental phosphate investments, some better than others.
Zero-D Products, Inc.
Precision engineered materials solutions