A vacuum forming apparatus for forming a tire, wheel, or other item in a mold having a cavity with the shape of the item to be cast that is contained in the apparatus. The vacuum forming apparatus utilizes a bell shaped outer cover arranged to seal along its lower edge to a mold base plate, and includes a canister maintained under a deep vacuum and arranged in or connected to the apparatus as a reservoir to receive a mixture of urethane constituents, with the deep vacuum removing air from that mixture, and the air free mixture is passed through a valve and into the mold cavity. A low level vacuum is pulled through a vent valve in the bell shaped outer cover to pull the flow of urethane material through the cavity, filling the mold. With the cavity filled, the canister valve is shut and the vent valve in the bell shaped outer cover is closed, allowing the urethane material in the mold cavity to cure, and the mold is broken open and the cast item is removed from the cavity.