My casting has bubbles. Do I need a vacuum chamber or a pressure pot?
They do different jobs, pick by what you're pouring:
- Vacuum chamber, degasses the mixed material before pouring, pulling trapped air out. Best for silicone molds, where you want a bubble-free mold surface. Most silicones can be vacuum degassed; very fast-setting ones can't (they'd kick before you finish).
- Pressure pot, shrinks any remaining bubbles in the curing part by curing it under pressure. Best for clear and rigid resin castings, where even tiny bubbles show.
No equipment? Reduce bubbles anyway: Mix slowly to avoid whipping in air, pour in a thin stream from a height into one low corner (let it flow up through the mold), and tap/vibrate the mold. Warming resin slightly lowers viscosity so bubbles rise out faster.
For high-clarity clear resin, a pressure pot is the single biggest quality upgrade. For detailed silicone molds, vacuum degassing is essential.
Learning Center:
Full guide: Bubbles, Voids and Degassing