Bubbles in the mold opening process of liquid silicone will seriously affect the beauty of the silicone mold, which makes us very helpless, especially for people without vacuum machine is more confused. The following is to share with you the skills of reducing the silicone bubbles in the mold without vacuum machine.


First of all, we will analyze the causes of bubbles. The first reason is that the bubbles brought into the mixture of silica gel and curing agent are not removed. Therefore, we should stir in the same direction when we stir, and let the bubbles float up for a period of time after mixing.


Secondly, when filling glue, we'd better let the liquid silicone flow down slowly in a filamentous way, so as to eliminate the bubbles while pouring glue. After filling, the bubbles on the surface can be punctured with a toothpick.


In addition, we can also prolong the curing time by controlling the proportion of silicone and curing agent, so as to gain time for the natural discharge of bubbles. For example, if the ratio of silicone and curing agent is 4%, we can reduce it to 2%, so that the cross-linking time of silicone in the early stage of the mold will increase, and the air in the mold will be slowly discharged to reduce bubbles.


The second reason is that the formula of liquid silicone raw materials contains a small amount of volatile impurities, which are easy to vaporize and form bubbles when heating and curing, so we try to use room temperature curing when curing, or take low temperature baking method, so that these impurities volatilize first, so as to reduce bubbles.


Some mold developers are used to adding silicone oil dilution to silicone, to increase the fluidity of liquid silicone, to facilitate the elimination of bubbles (low viscosity silicone is easier to exhaust bubbles), but we recommend that the amount of silicone oil added should not exceed 5% at most, because the amount of silicone oil added too much will destroy the molecular weight of silicone, resulting in the silicone mold will produce acid and alkali resistance, aging resistance phenomenon.