I have been careful in offering low tech ideas but I have found a
vibrating sander for wood working quite effective for removing
bubbles. Cheapies can often be found at flea markets, garage sales
etc. I mix the investment and place on the sander and then pour
slowly over the piece and vibrate lightly at intervals as I fill the
flask. It is often possible to see the bubbles as the filling
progresses. Be sure the piece is well secured in the base. I had one
sander that was quite aggressive in its action and dislodged the wax
from the base. Had to clean the the mess and reinvest- no damage
done just a waste of time. Cary