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Casting resin in a silicone mold works best with a clean, dry mold, exact mix ratios, a slow pour, and patience until the resin reaches full cure.
For the full breakdown, see our best Epoxy for Casting Sculptures Over 2 Inches Deep guide.
A beautiful cast usually fails before the resin touches the mold — the first ten seconds, not the last hour, are where most pours go wrong. This guide covers how to cast resin in silicone molds without stuck parts, bubbles, or tacky surfaces, using the same workflow pro shops rely on. Get the prep right and the demold takes care of itself.
Do You Need A Release Agent For Silicone Molds?
No — for most standard casts, silicone is non-stick and flexible enough that a release agent is optional. The mold bends away from the cured part, which is exactly why silicone preserves fine detail so reliably.
Use a release agent for deep undercuts, older molds, or when the mold manufacturer recommends one. If you do, pick a release made for resin casting and stick to pigments and additives approved for your resin system. Work in a well-ventilated area with gloves, and wear a mask so resin fumes stay out of your lungs.