Systems and methods for mounting of material samples via a vacuum system and controlling fluid flow through a tube of the vacuum system are disclosed. In some examples, the vacuum system may be a castable and/or cold mounting vacuum system that facilitates mounting and/or encapsulation of material samples in epoxy resin under low, vacuum, and/or near vacuum pressure. In some examples, the vacuum system may comprise a flow control device configured to control epoxy flow through a dispensing tube that connects to a hollow vacuum chamber. In some examples, the vacuum chamber may have an opening defined by a rim sandwiched between upper and lower portions of a sealing ring. A movable lid may be configured to press down on the upper portion of the sealing ring when in a closed position, so as to seal the opening.