In general,curing time will be short with high temperature.so should add catalyst according the temperature.if add too much catalyst,the silicone molds will become hard and brittle.conversely,if add too little catalyst,pot life time will be longer than before. But when pouring molds,must add little catalyst,so that can make prefect molds according to long curing time.
Ratio of silicone and catalyst at room temperature as below:
1.with 1% catalyst,the silicone also is liquid when mixed after 2.5hrs,demold time about 6-8 hrs.
2.with 2% catalyst,the silicone also is liquid when mixed after 50-60mins,demold time about 2-3 hrs.
3.with 3% catalyst,the silicone also is liquid when mixed after 10-15mins,demold time about 1-1.5hrs.
Ratio of catalyst with different temperature as below:
1.the silicone will not cured after mix with catalyst when the temperature below 5℃.
2.The ratio of catalyst can’t more than 5% when the temperature about 10℃.
3.the ratio of catalyst should be 2%-3% when the temperature about 25℃.
4.The ratio of catalyst can be 1% when the temperature about 38-45℃.
So we can conclude that the ratio of catalyst can’t less than 1%,otherwise the silicone will not cured for a long time.also can’t more than 5%,because it will affect the hardness ,tear strength and tensile strength of silicone.it is best with 2%-3% catalyst and mixing at the temperature about 30℃.