Atlas of Casting Defects
Positive
Small, smooth spherical, oval or elongated tubular shaped positive
1/8” or less
Difficult to wet out areas during shell building
Bee Bees, Air bubble
Visible to eye. Smooth surface of defect
Air trapped against the wax pattern by the primary slurry layer
| Area | Possible Cause | Potential Correction |
|---|---|---|
| Wax or Mold Design | Bad mold design |
Re-orient the part to prevent air from being trapped during dipping |
| Shell | Poor dipping technique |
Immerse the pattern slowly in the slurry, use vibration or, compressed air or vacuum to pop any trapped air bubbles |