Metallurgical work concentrated on uranium and plutonium. Although it had been discovered over a century before, little was known about uranium, as evidenced by the fact that many references gave a figure for its melting point that was off by nearly 500 °F (280 °C). Edward Creutz investigated it and discovered that at the right temperature range, uranium could be hammered and rolled, and drawn into the rods required by the production reactor design. It was found that when uranium was cut, the shavings would burst into flame. Working with Alcoa and General Electric, the Metallurgical Laboratory devised a method of soldering the aluminum jacket to the uranium slug.