Making a Dinosaur

Making a Dinosaur. . These and other models were built by artist Louis Paul Jonas (1894-1971) under commission by Sinclair Oil Company for its exhibit at the New York City World's Fair of 1964 and 1965. , Jonas began with hundreds of sketches and models, resulting in a single, detailed clay replica of each animal one-tenth actual size. He projected photographs of each scale model onto wallboards which he cut to serve as full-scale frames for the next step. , Jonas then stretched a screen-wire shell around the board frames, adding burlap and plaster for general shape. Next, he added several tons of modeling clay and sculpted skin and facial details. , When the clay shell dried, Jonas cut it up (the brontosaur required 86 pieces) and used each piece to make plaster molds. Into these molds he poured a mixture of fiberglass and polyester resin. When the plastic set, he bolted the resulting pieces to special frames of paper tubes filled with concrete. After filling and smoothing the seams, he sand-blasted, washed and painted the skin.