Disclosed are embodiments of a vessel configured to contain a secondary magnetic induction field therein for melting materials, and methods of use thereof. The vessel can be used in an injection molding apparatus having an induction coil positioned adjacent to the vessel. The vessel can have a tubular body configured to substantially surround and receive a plunger tip. Longitudinal slots or gaps extend through the thickness of the body to allow and/or direct eddy currents into the vessel during application of an RF induction field from the coil. The body also includes temperature regulating lines configured to flow a liquid within. The temperature regulating lines can be provided to run longitudinally within the wall(s) of the body between its inner bore and outer surface(s). A flange may be provided at one end of the body to secure the body within an injection molding apparatus.