Ever experience troubleshooting issues with investment casting? We have put together a list of possible defects, the cause and the solution that should solve the problem.

Cracking Quenching too soon Wait 15-20 minutes
Cracking Metal cast too soon Increase casting temperature
Cracking Flask too cold Increase flask temperature
Cracking Incorrect spruing Modify sprueing
Cracking Contamination of gold or alloy Refine metal
Cracking Oxide build up in metal, over-use Refine metal
Cracking Hydrochloric acid divesting Use alternative di-vestor
Incomplete Fill Metal too cold Increase casting temperature
Incomplete Fill Flask too cold Increase flask temperature
Incomplete Fill Insufficient vacuum Check vacuum for leaks and seal
Incomplete Fill Wrong speed on centrifugal caster Adjust speed
Incomplete Fill Insufficient burn out Modify sprue
Incomplete Fill Incomplete burn out Use proper burn out schedule
Inclusions in castings Sharp corners or bends in sprueing Round out sharp corners and bends
Inclusions in castings Crucible old and deteriorating Replace Crucible
Inclusions in castings Oxide build up in crucible Clean or replace crucible
Inclusions in castings Foreign particles or oxides in metal Refine metal
Inclusions in castings Investment erosion or breakdown Follow investment manufacturer's mixing instructions
Brittle prongs on castings Improperly alloyed metal Pre-alloy gold and master alloy
Brittle prongs on castings Flask temperature too cold Increase flask tempretature
Shrinkage porosity Incorrect sprueing Sprue to heaviest area of casting
Shrinkage porosity Inadequate sprueing Use larger sprue or multiple sprues
Shrinkage porosity Flask too hot Use lower flask temperature
Shrinkage porosity Castings too close to sprue button Leave 1" space on tree above main sprue button
Gas porosity Metal overheated Reduce casting temperature
Gas porosity Inadequate burn out Increase top end burn out time
Gas porosity Inadequate air supply during burn out Assure oven has good air supply & exhaust
Gas porosity Flask too hot Reduce flask temperature
Gas porosity Scrap reused too many times Refine metal
Gas porosity Too much oxygen on torch flame Use reducing flame when melting
Gas porosity Investment residue on remelted scrap Remove investment residue before remelting scrap
Rough castings Flasks not cured before burnout loading Let flasks set 1-2 hrs. before burnout loading
Rough castings Incorrect water/powder ratio in investment mix Follow investment manufacturer's instructions
Rough castings Flasks heated too rapidly Follow investment manufacturer's instructions
Bubbles/nodules on castings Investment not mixed, vacuumed or vibrated sufficiently Follow investment manufacturer's instructions
Bubbles/nodules on castings Vacuum pump not working properly Check vacuum pump oil
Bubbles/nodules on castings Wax patterns not coated with wetting agent Coat wax patterns with wetting agent