Abstract: A method of making plastic containers having walls with fluid circulatable channels integrally formed therein comprises the successive steps of injecting a molten thermoplastic material in a mold cavity having a channel configuration to define, in the container being mold, walls with thicker portions defining a rib configuration, injecting a pressurized fluid throughout the rib configuration to displace molten material therein and to form a hollow channel therein, cooling the container being mold removing the molded container from the mold and cutting through the hollow channel at two spaced locations to form inlet and outlet openings to the channel to thereby enable circulation of a fluid through the channel.

Abstract: A snowmobile steering ski has an elongated one-piece blow molded body formed of polyethylene, preferably ultra high molecular weight polyethylene. The top wall of the body has raised portions defining hollow sections with the bottom wall and displays a central recessed area adapted to receive the lower end of a snowmobile steering component. A pair of fixation holes are provided in lateral sides of the recessed area for fixing the steering component to the ski while further fixation holes are provided in the bottom of the recessed area for fixing a wear bar to the under face of the body.