The first method: we can use silicone oil to reduce the hardness of silica gel. Generally, adding 1% silicone oil will reduce the hardness of silica gel by about 0.9 ~ 1.1 degrees; Adding 10% silicone oil will reduce the hardness of silica gel by about 5 degrees. However, in practice, if the added silicone oil ratio is too high, the molecular weight of silica gel will be damaged, and the tear resistance and tensile strength will deteriorate accordingly, which will affect the service life of silica gel mold. In addition, too large the added silicone oil ratio will also lead to the easy deformation of silicone rubber mold. Therefore, we suggest: generally, the ratio of silica gel to silicone oil should not exceed 5%, and try to add silicone oil with higher viscosity. If more than 5% silicone oil is added, please try a small amount first to determine whether the mold can be used.

The second method: mix high hardness silica gel and low hardness silica gel. The premise of using this method is that you buy two kinds of hardness silica gel, such as 20 hardness silica gel and 10 hardness silica gel. After mixing, the hardness of silica gel is about 15 shore a. When using this mixing method, it should be noted that the condensation type can not be mixed with the addition molding, otherwise it will cause non curing.