Apparatus comprising a melter tank (11), a pump (12) contained within the melter tank (11), a dispenser, and a manifold block (13) mounted on the bottom of the melter tank (11). Thermoplastic material melted in the tank (11) flows from the melter tank (11) through the pump (12) through the manifold block (13) to the dispenser. The melter tank (11) comprises a novel electrical resistance heating element (80) cast into the bottom wall (14) of the tank (11). The heating element (80) is asymetrically shaped within the bottom wall (14) of the melter tank (11) and is so configured that the length of the heater element (80) within any portion of the bottom wall (14) is proportional to the mass of material, including melter tank (11), manifold block (13), pump (12), and thermoplastic material to be heated by the given length of heater element (80) within that portion. Additionally, the tank (11) side walls are generally triangular in cross section with the thicker part of the triangular shaped side walls located adjacent the bottom of the tank. A portion of the heating element (80) is located directly under each side wall so that heat is effectively conducted from the bottom wall (14) into the side walls (36,38), and from the side walls (36,38) into the thermoplastic material contained within the tank (11).