Silicone And Casting

1. Why do some solidify and some don't solidify at the same time?

Uneven mixing will cause slow local curing or non curing. For example, the curing time of the glue prepared at the same time is not consistent, some of which are cured quickly, and others can only be cured for a long time; after curing, there are grooves on the surface of the glue, and the glue in the groove does not solidify; and there is no curing phenomenon in some parts. It is necessary to strengthen the mixing. The mixing time is about 2 ~ 5min, so that the glue is completely mixed evenly. When mixing, it is necessary to pay attention to whether the mixing can drive all the rubber materials.

2. Can it be cured by heating?

In the curing process of condensed products, small molecules are produced, so it is not suitable for heating and curing. Generally, it takes more than 12 hours for the complete curing of general products. During this period, it is not suitable for heating aging, otherwise the evaporation speed of small molecules will be accelerated and the expansion phenomenon will occur; in addition, the curing temperature shall not exceed 45 ℃, and heating will accelerate the reaction, resulting in a large amount of ethanol gas generated in a short time, resulting in a large number of bubbles or pores.


3. Mixing process

1) The main agent and curing agent should be used according to the recommended weight ratio a: B = 10:1 (error no more than 0.2%)

2) Before use, the main agent and curing agent shall be fully mixed and mixed according to the specified proportion.

3) Stir for 2-5 minutes at 1500-2000 rpm. The agitator should be placed at the position slightly deviated from the liquid level center. The best depth of the agitator inserted into the glue is 1 / 22 / 3 of the glue liquid height (based on the height from the liquid level).

4) After evenly stirring, the rubber compound will be vacuumed (if necessary) so that the bubbles can be completely removed, and then pouring can be carried out.

5.)Components a and B that have been opened should be re sealed, otherwise the curing performance will be affected.

Link to this article:What Are The Problems Of Silicone Rubber In Condensed Mold

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