Silicone Thinner

Synonym: silicone fluid

Silicone Thinner is a clear non-reactive silicone fluid that reduces the mixing viscosity of tin-cured (condensation) or platinum-cured (addition) liquid silicone rubber. Silicone thinner can be used to reduce the viscosity of any mold making silicone, making it easier to get it into small details and helping to improve degassing by making trapped air bubbles escape more readily.

The thinner will increase working time and decrease final hardness and tear strength. Recommends only adding 3% to 5%. It is not recommended to exceed 10% by weight of total system (A+B). Adding too much silicone fluid can adversely effect the physical properties of the silicone itself. Tear and tensile strength will be the most greatly effect properties if too much silicone thinner is used.

silicone thinner

For example:

When adding 5% of silicone thinner to your silicone rubber, it will reduce the mixed viscosity by 24%, the shore hardness by 13%, the tensile strength by 13% and the tear strength by 12%.

When adding 10% of silicone thinner to your silicone rubber, it will reduce the mixed viscosity by 45%, the shore hardness by 23%, the tensile strength by 18% and the tear strength by 16%.


1. Reduces air bubbles: A lower mixed viscosity (A+B) means that the rubber will de-air faster when vacuuming.

2. Lowers mixed viscosity: Mixed rubber (A+B) will flow better over intricate model detail.

3. Effects on cured silicone: Tear strength, tensile strength and shore hardness are reduced in proportion to how much silicone thinner is used.

4. Silicone thinner will increase the pot life of the silicone and will slow the rate at which it cures. Pot life (working time) is increased in proportion to the amount of silicone thinner used.


1. Materials should be stored and used in a warm environment 70F/23° C. Wear safety glasses, long sleeves and rubber gloves to minimize contamination risk.

2. Silicone Thinner is added as a percentage of the total Part A+Part B rubber system. An accurate gram scale must be used. Weigh out and pre-mix the required amount of silicone thinner with Part A of silicone rubber before adding Part B.

3. Because no two applications are quite the same, a small test application to determine suitability for your project is recommended if the performance of this material is in question.