Choosing a mold
Silicone molds flex so castings pop out without damage. For coasters, jewelry and small castings, a thin silicone mold is fine. For deep pours, choose a mold with thick walls so it holds shape under the resin's weight.
Do you need release agent
Most silicone molds release clean without anything. A light spray of mold release extends mold life and helps with complex shapes, but too much leaves a dull surface on the casting.
Preparing a new mold
- Wash with warm soapy water and dry fully.
- Set it on a level surface.
- Optional: mist a thin layer of release agent and let it dry.
Materials that work
- Silicone: best for detail and casting.
- HDPE plastic: good for simple shapes; needs release agent.
- Wood molds: seal first or the resin will bond to the grain.
- MDF: seal with epoxy or a mold sealer before use.
Extending mold life
Demould as soon as the resin is hard enough, clean with warm soapy water, and store flat away from sunlight. Avoid tearing the mold off a casting that is still soft.
Frequently asked questions
Can I use a baking mold?
Only if it is silicone and dedicated to resin. Never use it for food afterwards.
Why does my casting have a dull side?
Usually too much release agent or a scratched mold.
How many pours does a mold last?
20 to 50 pours for hobby silicone with care.
Related reading
Browse molds and tools or read epoxy jewelry.
