The joining of plastics refers to the joining of semi-finished parts. This includes fastening, adhesive bonding, and welding. Fastening refers to the incorporating latches, hinges and snap fits into the design of the part, or using external fasteners such as bolts and screws. Adhesive bonding means the application of an adhesive (such as epoxy) to join parts together. Welding refers to the joining of two parts via the application of heat and pressure. As the parts are already semi-finished when they are prepared to be joined, many of the process specifications for joining are dependent on the manner in which the semi-finished parts were made. Though joining is dependent on part shape, this process can be time consuming and incur a high labor cost.