Processing extruded vinyl siding

An apparatus for manufacturing thermoplastic house siding comprising an extruder for extruding an elongated cross-sectioned house siding panel with L-shaped end portions, a cooling tank mounted adjacent to said extruder, said cooling tank having a forward end and a rear end portion, a sizing die located at said forward end portion and said rear end portion of said cooling tank, and annealing tank, said annealing tank having a forward portion and a rearward portion, said forward portion of said annealing tank mounted closely adjacent to said rear end portion of said cooling tank, a sizing die mounted in said forward portion of said annealing tank, a sizing die mounted in said rear end portion of said annealing tank, a sizing die mounted in the intermediate portion of said annealing tank, a quenching tank, said quenching tank having a forward portion and a rear end portion, said forward portion of said quenching tank mounted adjacent to said rear end portion of said annealing tank, a sizing die mounted in said forward portion of said quenching tank, a sizing die mounted in said rear end portion of said quenching tank, means connected to each of said tanks for controlling the flow of fluids into and out of said tanks, temperature control means connected to said cooling tank to maintain the temperature range therein to between 50.degree. F. and 212.degree. F., and temperature control means connected to said annealing tank to maintain the temperature therein from 160.degree. F. to 212.degree. F.