Short answer: use a release agent on hard molds (plastic, metal, wood, epoxy) and on models you're making a mold from, because epoxy bonds to most surfaces. Follow your silicone mold or rubber maker's guidance for silicone, and test any release on a small piece first, since release can dull a glossy finish.
| Product | What it releases (as listed) | Listed temperature range | Notes | Source |
|---|---|---|---|---|
| Ease Release 200 | Polyurethane elastomers, epoxy resin, polyester resins, RTV silicones, rubber, thermoplastics; for aluminum, chrome, RTV silicone, epoxy, rubber and steel molds | 70–500°F | Spray 6–8 in from the mold for a light, even coat; season new molds with a heavier coat | smooth-on.com |
| Universal Mold Release | Mold rubbers (e.g. polyurethanes, polysulfides) from models; casting materials such as epoxies from cured rubber molds | 70–500°F | Not for making silicone rubber molds: Smooth-On says to seal the model with SuperSeal instead | smooth-on.com |
Both pages note a limited shelf life and call for ventilation, safety glasses and gloves. Read the technical bulletin and SDS before use.
Next steps: work out how much resin fills the mold with the mold volume calculator, make your own mold with how much silicone for a mold, or buy one: best silicone molds for resin.
On hard molds and models, yes: epoxy bonds to most surfaces. For silicone molds, follow the mold maker's guidance; release can extend mold life.
It isn't made for this: it can leave residue, spoil the finish and affect curing. Use a release made for epoxy.
A heavy coat can dull the surface. Use a light, dry coat and test on a small piece first.
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