mould making liquid silicone rubber to make mold for concrete garden

General Description:
RTV-2 molding silicone rubber and silicone rubber are general called two-component room temperature vulcanization silicone rubber with excellent fluidity and good operational performance. Add curing agent of 2%-3% at the room temperature, the silicone rubber is still operational within 30 minutes,and in 2-5 hours, an elastic silicon mold will be obtained with resistance to deformation, high-temperature, acid and alkali and expansion. The silicone rubber is mainly applicable to mold duplication of poly crafts, resin craftworks, lightings, candles, etc. and fabrication of precision molds.

Operation Instruction for RTV-2 Molding Silicone Rubber:
The product is white or red flowing liquid with general hardness of 34—38A°after curing . If the customer wants to make large products and large size molds, the mold should be made of silicone rubber with high hardness. On the contrary, if the mold with fine and precision patterns , it should be made of silicon with low hardness. The amount of the curing agent depends on the actual requirements of the customer. If molds requiring fast drying and demould, more curing agent is needed; contrarily, if molds requiring slower drying and demould, less curing agent is needed.
(Note: our company does not recommend you to add silicone oil. If a special soft silicon mold or fine detailed and complex patterns products are required, 5%-10% silicone oil can be added to soften the mold for easy demould.)

The proportions and reactions of the curing agent and the silicon are listed as follows:
1. Adding curing agent 1%, the silicone can still be operated within 2.5 hours and can be demoulded after 6-8 hours.
2. Adding curing agent 2%, the silicone can still be operated within 50 minutes to 1 hour and can be demoulded after 2-3 hours.
3. Adding curing agent 3%, the silicone can still be operated within 28 - 30 minutes and can be demoulded after 1.5-2 hours.
4. Adding curing agent 4%, the silicone can still be operated within 10 - 15 minutes and can be demoulded after 1 -1.5 hours.

Why could the silicone mold be reused only for a few times?

It can be due to the following reasons: 

a. Adding too much silicone oil in to silicon rubber. Silicon oil is an additive which destroies the molecular weight 

of silicone rubber and reduce the tension and tear strength.

b. Using the silicon rubber with a high hardness to make molds for small sized products with delicate and intricate 

designs and the silicon rubber with a low hardness to makes molds for large sized products with simple designs. 

(Notes: we should choose the silicon rubber specifically according to the requirements of our products to avoid 

this problem.)