RTV-2 silicone rubber and polyurethane are commonly used materials when making silicone mold casting resin, because these materials have a certain viscosity, mixing and stirring will produce bubbles, the most common tool to remove the bubbles is a vacuum pump, the above video explains the use of vacuum pumps and precautions in great detail through example operations.
The purpose of the vacuum pump is to remove as much air as possible from your chamber in a short time. It is very suitable for degassing resins with a short pot life or used in a production environment with fast turnover, but it is also fully suitable for a variety of Degassing materials, such as RTV silicone rubber, urethane resin, urethane rubber and epoxy resin casting resin.
The time to run the pump depends on the amount of silicone you degas and the size of the chamber. Before mixing the silicone, please consider the time required to add the two parts of silicone and mix, the time required to vacuum in the chamber, the time required to degas the silicone, and the time to pour the silicone into the mold box. The greater the amount of silicone, the longer the time required for degassing. All these hours should be less than your open working hours for that particular silicone.
Vacuum pumps for silicone and resin degas are relatively small. They do not take more than a square foot on your work table or floor. They do not vibrate and can be easily placed on the same table as your vacuum pot or other equipment. Vacuum pumps that small do not make much of a noise. Their humming is relatively low. Considering that the degassing of silicone takes only minutes the noise the pump makes should not be a concern when picking your pump.
Because vacuum pumps require oil to run there is a very slight odor they produce. It is not irritating at all, and it's gone as soon as you turn the pump off.