Smooth-On Mold Star 16 Fast Platinum Silicone Rubber - Fast-Cure Mold

In this review of the Smooth-On Mold Star 16 Fast platinum silicone rubber kit, the bottom line is clear: this pint unit is aimed at artists, sculptors, and small-scale fabricators who need a fast-curing, tear-resistant silicone for repeatable molds. The reviewer found it especially useful for projects where a quick turnaround matters, because the material sets rapidly and produces soft but durable molds. For anyone making small to medium casts or prototypes, the combination of low viscosity and low long-term shrinkage makes this kit a practical choice when vacuum degassing is not feasible.

Key Features

• Fast cure: The formula sets quickly, enabling faster project cycles and minimizing wait time between molding and casting.
• Low viscosity: Easier flow into fine details and undercuts means less trapping of air and simpler pours without constant thinning.
• No vacuum usually required: Most small-scale applications do not need vacuum degassing, which saves equipment and prep time.
• Tear-resistant rubber: Molds cure to a soft, strong, and tear-resistant rubber that holds up to repeated use.
• Low long-term shrinkage: Finished molds retain dimensional accuracy over time, useful for repeatable casting runs.

Who It's For

The Smooth-On Mold Star 16 is best for hobbyists, prop makers, and small studio artists who need a reliable, fast-curing silicone for silicone molds used in resin, plaster, or low-temp casting. Its relatively low viscosity and the fact that vacuum degassing is not required make it suitable for makers working in limited workshop setups.

Those doing very large industrial molds, multi-part tooling for heavy production, or projects requiring extended pot life and slow working times may prefer a different grade. Also, anyone unfamiliar with silicone mixing should follow the technical bulletin and perform a small-scale test before committing to a critical piece.

Pros & Cons

Pros

• Fast cure time lets users complete small projects quickly without long waits.
• Soft yet tear-resistant cured rubber extends mold life for multiple casts.
• Low viscosity improves detail capture and reduces the need for vacuum degassing.
• Low long-term shrinkage preserves part accuracy across runs.

Cons

• Cures quickly enough that some users may find working time limited for complex pours or multi-part molds.
• Requires careful mixing until the mixture shows a uniform color; color streaks indicate incomplete mixing.

Specifications

Product	Smooth-On Mold Star 16 Fast platinum silicone rubber
Unit size	Pint unit
Cure speed	Fast-curing formulation
Viscosity	Relatively low viscosity for mold rubbers
Degassing	Vacuum degassing not required for most applications
Rubber properties	Soft, strong, tear-resistant with low long-term shrinkage
Mixing note	Mix until uniform color; perform small-scale test per technical bulletin

Our Verdict

The Mold Star 16 Fast is a strong choice for artists and small fabricators who need quick cures and reliable, tear-resistant silicone molds without investing in vacuum equipment. It offers solid value when used for small to medium projects and when mixed carefully to avoid color streaking and premature set-up.

Frequently Asked Questions

Do I need a vacuum chamber to use this silicone?
In most small-scale applications no vacuum degassing is required thanks to the low viscosity, though delicate detail may still benefit from degassing.

How will I know when mixing is complete?
Mix until the material reaches a uniform color; any color streaks indicate incomplete mixing and can affect cure and strength.

Can I use this for multiple casts?
Yes, the cured rubber is soft and tear-resistant, suitable for repeat casts on small to medium projects when handled properly.