When the upper half of the mould had hardened it was turnedupside down and a moulding tray for the lower half was built on tiop of it. This has a grid in its base that the sand would stick to swo that the whole mould can be moved by crane the right way up. The chills were carefully placed in position around the rim of the pattern. Spaces were left between them to allow for expansion of the chills during the casting process.