An infrared welding apparatus for welding a fluid reservoir for a vehicle washer system, wherein the reservoir is defined by a first reservoir portion and a second reservoir portion partially nested together with an overlapping portion, wherein the overlapping portion is a weld, comprising: • a first weld portion defining a first weld cavity to receive the first reservoir portion; • a second weld portion defining a second weld cavity to receive the second reservoir portion; • a first infrared light array, configured to be placed concentrically surrounding the first reservoir portion during the weld process, in an area corresponding to what will be the overlapping portion; • a second infrared light array, configured to be placed concentrically inside the second reservoir portion during the weld process, in an area corresponding to what will be the overlapping portion and at the same time parallel to the first infrared light array, wherein the first infrared light array and the second infrared light array are configured to apply infrared heat to the first reservoir portion respectively the second reservoir portion; • a pair of slides configured to surround the overlapping portion of the first reservoir portion and the second reservoir portion concentrically, when the first reservoir portion, first weld portion, second reservoir portion and second weld portion are assembled together; • wherein pressurized air is foreseen to be pumped into the fluid reservoir, after the first reservoir portion, the first weld portion, the second reservoir portion, the second weld portion and the slides are assembled together in order to force the overlapping portion outward against the slides to weld the first reservoir portion to the second reservoir portion. • a first weld portion defining a first weld cavity to receive the first reservoir portion; • a second weld portion defining a second weld cavity to receive the second reservoir portion; • a first infrared light array, configured to be placed concentrically surrounding the first reservoir portion during the weld process, in an area corresponding to what will be the overlapping portion; • a second infrared light array, configured to be placed concentrically inside the second reservoir portion during the weld process, in an area corresponding to what will be the overlapping portion and at the same time parallel to the first infrared light array, wherein the first infrared light array and the second infrared light array are configured to apply infrared heat to the first reservoir portion respectively the second reservoir portion; • a pair of slides configured to surround the overlapping portion of the first reservoir portion and the second reservoir portion concentrically, when the first reservoir portion, first weld portion, second reservoir portion and second weld portion are assembled together; • wherein pressurized air is foreseen to be pumped into the fluid reservoir, after the first reservoir portion, the first weld portion, the second reservoir portion, the second weld portion and the slides are assembled together in order to force the overlapping portion outward against the slides to weld the first reservoir portion to the second reservoir portion.