How to choose silicone casting materials?
Types of silicone:
Room temperature vulcanized silicone (RTV): can be cured without heating, suitable for small batch manual operation, divided into condensation type (need to be exposed to air moisture for curing, may release by-products) and addition type (platinum catalysis, environmentally friendly and non-toxic, no by-products during curing).
High temperature vulcanized silicone (HTV): needs to be heated (100-200℃) for rapid curing, suitable for industrial mass production, with better strength and high temperature resistance.
Hardness and characteristics: select Shore hardness (such as 00-100 degrees) according to needs, such as soft glue (0-20 degrees for simulated skin), hard glue (40-80 degrees for mold); consider tear resistance, chemical resistance, transparency, etc.
2. Mold preparation
Mold material: commonly used silicone, gypsum, metal (aluminum/steel), plastic (such as ABS), need to be selected according to the type and complexity of silicone.
Mold processing:
Cleaning: remove grease and dust to avoid affecting the adhesion of silicone.
Demolding treatment: Apply a release agent (such as vaseline, special silicone release agent) or perform surface hydrophobic treatment to ensure easy demolding after curing.
Parting design: Complex molds need to design parting surfaces, reserve injection ports and exhaust holes (to avoid bubble residue).
3. Equipment and tools
Mixing tools: electronic scale (accuracy 0.1g), stirring cup, stirring rod (silicone and curing agent need to be mixed in proportion, such as addition type usually 1:1 or 10:1).
Infusion tools: syringe (for small volume), pressure tank (used for vacuum infusion), pouring cup (with guide nozzle).
Auxiliary equipment: vacuum pump (vacuum degassing), oven (used for high temperature vulcanization), thermometer.