The use tips of liquid silicone involve many aspects, including proportioning, degassing, pouring and brushing, curing and demoulding, etc. Here are some detailed tips for using liquid silicone:
1. Proportioning and mixing
Accurate proportioning: The ratio between liquid silicone and curing agent needs to be precisely controlled. Generally speaking, the common ratio is 100:2, that is, 2 grams of curing agent is added to every 100 grams of silicone. For some special types of liquid silicone (such as addition-type liquid silicone), the ratio of components A and B may be 1:1, which needs to be determined according to the product manual.
Full mixing: Use a stirrer to mix the silicone and curing agent thoroughly and evenly to ensure that no granular substances remain. Uneven mixing may cause incomplete curing of the silicone or degradation of its performance.
2. Degassing bubbles
Vacuum exhaust: The prepared liquid silicone should be degassed with a vacuum machine. Put the silicone raw material into the vacuum machine and vacuum it. Generally, the bubbles can be removed in about ten minutes. Note that the vacuuming time should not be too long to prevent the silicone from cross-linking and curing prematurely.
Standing and observing: After the bubbles are exhausted, let the silicone stand for a while to observe whether new bubbles are generated. If necessary, the bubble removal process can be performed again.
3. Infusion and painting
Slow infusion: Pour the processed liquid silicone raw material slowly on the product or in the mold, allowing it to flow naturally into every corner. Pay attention to controlling the infusion speed to avoid generating new bubbles.
Multi-layer painting: For products or molds that need to be painted, they should be painted in multiple layers. After each layer of painting, wait for the silicone to solidify before painting the next layer. During the painting process, reinforcing materials such as fiberglass cloth can be added to improve the strength and durability of the mold.
4. Curing and demoulding
Controlling curing conditions: The curing speed of liquid silicone is closely related to temperature. At room temperature (such as 25°C), silicone usually takes 4-6 hours to fully cure. If you need to speed up the curing speed, you can increase the temperature appropriately (such as heating to 60°C). However, you need to be careful to avoid excessive temperature that may cause silicone performance degradation or deformation.
Timely demoulding: After the silicone is completely cured, you can perform the demoulding operation. Be careful when demoulding to avoid damaging the mold or product. For products or molds with complex shapes, a demoulding agent can be used to assist demoulding.
V. Other precautions
Storage and preservation: Unused liquid silicone should be sealed and stored in a cool, dry, ventilated place, away from direct sunlight and high temperature environment. Silicone that has not been used for a long time should be checked regularly to see if its performance has changed.
Cleaning and maintenance: After use, tools and equipment such as agitators and molds should be cleaned in time to avoid silicone residues that may cause performance degradation during the next use. At the same time, regularly maintain and service the mold to extend its service life.