Short answer: a pot rated well above your working pressure (casters commonly run about 40–60 psi; the pot's rating, not the compressor, sets your limit), with a gauge, a pressure-relief valve, and enough inside height for your molds.
| If you want… | Look for |
|---|---|
| Bubble-free clear castings (pens, dice, jewelry) | Pressure pot: squeezes bubbles too small to see while resin cures |
| Degassing silicone before pouring molds | Vacuum chamber (pulls bubbles out), then cure silicone at normal pressure or in the pot |
| Big or tall molds | Larger pot size; measure your tallest mold plus a support shelf |
| First-timers | Pot with a working relief valve and gauge; buy from a seller that lists its pressure rating |
A pressure pot is for curing resin under pressure; a vacuum chamber is for degassing silicone (and some slow resins) before pouring. Many casters use both. Resin cast under pressure should go into a pressure-rated silicone mold that won't deform.
Fewer bubbles without any equipment? See how to get bubbles out of resin and heat gun vs torch.
Never exceed the pot's rated pressure, use a regulator on the compressor, and release pressure before opening the lid.
Not for coatings or most art pours. It helps when you need bubble-free castings like pens, dice or clear jewelry.
Casters commonly use about 40–60 psi. Never exceed your pot's rating, and follow your resin maker's guidance.
Pressure shrinks bubbles while resin cures; vacuum pulls air out before pouring. Pressure is usually the better choice for resin castings, vacuum for silicone.
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