How do we know when we have a usable model for a rubber tool mold? Look for these important details:
- Stable: While silicone will harden against most surfaces... such as ice and ice (and even ice has curing length issues)... some surfaces are simply not going to hold their form long enough to get a good impression.
- Non-Porous: While it is temping to just carve rough styrofoam, floral foam, lava stone or other porous surface... toss on some silicone and save on worktime. Unless your foam is very dense... you could have problems de-molding. The same is true for bark and other kinds if wood or cement surfaces.
- Smooth: This is key. A rough surface will cause tiny bubbles to cling to the surface and ruin the mold. Small patterns and textured surfaces will require a detail coat of silicone pre mixed and applied before any large pouring of silicone.