Addition Cure (Platinum) vs. Condensation Cure (Tin) RTV-2 Silicone: Key Differences for Potting

Quick Answer

Addition cure (platinum) RTV-2 silicone cures with no by-products, low shrinkage, and high heat resistance, making it ideal for precision potting and mold making. Condensation cure (tin) silicone releases alcohol or water vapour, shrinks more, and is cheaper, suiting general-purpose molds and cost-sensitive work. For demanding electronic encapsulation, addition-cure silicone is usually the better choice.

Key Takeaways

• Addition cure = platinum catalyst, no by-products, low shrinkage.
• Condensation cure = tin catalyst, releases alcohol, higher shrinkage.
• Platinum systems offer better heat resistance and repairability.
• Choose addition cure for electronics, potting, and precision molds.

Addition Cure (Platinum) vs. Condensation Cure (Tin)

Why Platinum (Addition) Cure Is Preferred

• No by-products: nothing is released during cure, so there is no bubbling, odour, or corrosion risk.
• Low shrinkage: dimensions stay accurate — critical for potting and mold making.
• Higher heat resistance: stable performance up to 200 °C.
• Deep-section cure: cures evenly without relying on air moisture.
• Excellent repairability: supports rework of encapsulated components.
• Stable electrical insulation: consistent properties over the product’s life, ideal for long-life electronics.

When to Choose Condensation Cure

Condensation-cure (tin) silicone is a cost-effective option for general-purpose molds, prototypes, and applications where extreme temperature or precision is not critical. It is also more tolerant of contaminants, which can be useful in less controlled workshop environments. However, the alcohol released during cure and higher shrinkage must be considered for precision work.

Frequently Asked Questions

What is the difference between addition and condensation cure?

Addition cure uses a platinum catalyst and releases no by-products; condensation cure uses a tin catalyst and releases alcohol or water vapour during curing.

Which silicone cures faster?

Both can be accelerated with heat, but addition-cure systems typically offer more controllable, uniform curing.

Can platinum silicone be inhibited?

Yes — sulfur, tin, and amine contaminants can inhibit platinum cure, so clean handling and compatible materials are essential.

About Hanast

Hanast (Shenzhen Hanast New Materials Co., Ltd.) is a China-based source factory for RTV-2 liquid silicone and potting compounds. Established in 2010 with a 40,000 m² production base and an export-driven business (70–80% overseas), Hanast supplies OEM/ODM encapsulation and mold-making silicone solutions to global B2B clients. Learn more at silicone-liquid.com.