Short answer: a pressure pot is for curing resin castings bubble-free; a vacuum chamber is for degassing silicone (and some slow resins) before pouring. Most resin casters buy a pressure pot first.
| Criteria | Pressure pot | Vacuum chamber |
|---|---|---|
| What it does | Squeezes bubbles so small you can't see them while resin cures | Pulls air out of liquid before pouring |
| Best for | Clear castings: pens, dice, jewelry, inclusions | Mold-making silicone, some long-pot-life resins |
| Fast-curing resin | Works; resin stays under pressure while it cures | Often foams and gels before degassing finishes |
| Mold needs | Pressure-cast molds hold shape best | Any; done before the pour |
| Equipment | Pot + air compressor + regulator | Chamber + vacuum pump |
| Main safety point | Never exceed the pot's rated pressure | Leave headroom: material can expand several times in volume |
Next: how to choose a pressure pot (size calculator) · bubble fixes without equipment · silicone molds.
For resin castings, a pressure pot. A vacuum chamber is mainly for degassing silicone before you make molds.
Sometimes, with slow resins and enough container headroom, but many fast resins foam and start to gel. Pressure curing is usually more reliable for resin.
If you make your own silicone molds and cast clear resin, many casters use both: vacuum the silicone, pressure-cure the resin.
More tools: resin calculator · mix ratio by weight · cure time · mold volume · tabletop coating · pouring too thick
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