Effective Tips to Reduce Mold Liquid Silicone Bubbles

When we use liquid silicone raw materials to make silicone molds, because two-component silicone is a viscous liquid, in the mixing and stirring will produce bubbles, for those who do not have a vacuum pump is a very distressing thing, the following to share with you can effectively solve the experience of silicone mold bubbles tips.

For your convenience, we will explain step by step how to reduce bubbles in each step from the process of purchasing silicone raw materials to making silicone molds.

1. Silicone Raw Materials: Generally speaking, high-hardness silicone has a higher viscosity than low-hardness silicone. The higher the viscosity of the silicone raw material, the easier it is to produce bubbles. Therefore, we can choose low-hardness silica gel as far as possible, but the difference should not be too large. Because if the selected silicone is too soft, the silicone mold made is easy to deform and not durable, so it must be considered in a comprehensive manner. In addition, the liquid silicone raw material stored for a long time will also thicken and increase bubbles.

2. Blending Silicone: When it comes to blending silicone, let’s first understand the ratio between silicone and curing agent. Generally speaking, the more curing agent is added, the faster the curing and the shorter the operating time, so we can reduce bubbles by extending the operating time. At present, the ratio of tin-cured silicone on the market is generally 100:2~100:4. We can reduce the ratio of silicone and curing agent to 100:1~100:1.5 to extend the operating time and allow more time for bubbles. Eliminate, but pay attention to the ratio not less than 100:1, otherwise it will not be cured.

3. Pouring Silicone: When pouring silicone, try to pull up the distance, and let the liquid silicone drip into the highest point of the mold slowly and naturally, so that the liquid silicone can flow naturally in the mold frame, which is also a skill to reduce bubbles. In addition, you can use a brush to paint a layer of silicone on the surface of the master mold before pouring in, which can ensure that the air bubbles will not remain on the surface of the master mold.

4, Silicone Curing: Generally speaking, the higher the temperature, the shorter the operating time, the faster the curing speed, the curing agent in 0°C below will lose activity resulting in difficult to cure, so we can put the mold poured into the silicone into the refrigerator and wait After the bubbles are naturally eliminated, take them out,  but be careful not to contact the water droplets, you can wrap with plastic wrap, otherwise the liquid silicone will begin to end up unable to cure caused by scrap.

5, Auxiliary Materials: if the silicone mold performance requirements are not high, we can also add silicone oil to dilute in order to reduce the viscosity of liquid silicone, but the amount of silicone oil added should not be too high, otherwise it will appear after curing silicone mold oil seepage, tear resistance and tensile performance deterioration of the consequences.

To sum up: Choosing qualified and appropriate silicone raw materials, choosing the longest possible operation time, reducing the proportion of curing agent and lowering the curing temperature are all effective solutions to reduce bubbles in the silicone mold.


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