Melting kettles for use on vehicles for continuous processing of material for applying lines, stripes, bitumen, crack sealant or the like. The kettles disclosed herein provide heat transfer by use of oil jacketed tanks. A coil may be placed along a lower section for heat transfer through a burner for heating recirculated oil. A coil may be placed in a lower section and an upper section for heating an oil jacket, as well as heat transfer from the entire circumference of a coil placed in the upper section. An upper coil can be fluidly coupled to a lower coil and positioned within the chamber a spaced apart distance from the interior wall of the melter kettle. A mixer system rotates paddles to cause continuous transfer of material around the upper coil. The melter kettle is cylindrical, but can be corrugated to increase heatable surface area.