CASTING PROBLEMS

BLISTERS

BLISTERS

Possible Fault CauseSolution
First stage burnout hold too shortEnsure first stage burnout hold time at 220°C is 4.5 hours. If problem still occurs, increase hold to 5.5 hours.
Flasks de-wax at too high a temperatureEnsure first stage burnout temperature is kept in the range 220°C - 250°C (see burnout section).
Flasks placed in furnace too soon after investingDo NOT burn out before minimum 1 hour after investing.
Flask placed too close to or touching elementsLeave a minimum of 50mm gap between flasks and elements.
Blisters
flashing Rough Surfaces Non or Partial Fill bubbles