Short answer: platinum-cure silicone molds with a glossy inner surface for clear pieces and walls thick enough not to bow. Start with simple shapes (coasters, trays, cabochons) before deep or detailed molds.
| If you want… | Look for |
|---|---|
| Glass-clear coasters/trays | Glossy, platinum-cure molds (matte molds give a frosted finish) |
| Jewelry and small charms | Small cavity molds; pair with jewelry resin |
| Spheres and deep shapes | Casting epoxy rated for the depth; check mold volume first |
| A custom shape you own | Platinum-cure mold-making silicone kit |
| Lots of pieces to sell | Thick-walled molds; budget mold wear in your price per piece |
Platinum-cure silicone shrinks less, lasts longer and is usually the choice for resin molds. Tin-cure is cheaper but tends to wear faster with epoxy. Most finished molds sold for resin are platinum-cure; for DIY kits, check the label.
Usually not, since epoxy does not stick to silicone. A release spray can help with intricate molds and extend mold life.
The mold has a matte or scratched surface, or moisture was present. Use glossy molds and dry them fully.
It varies with silicone type, pour size and heat. Expect a mold to dull over time; thick platinum molds last longest.
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