During a recent factory visit to a systems manufacturer, Norman and Underwood in the East Midlands, we had a rare opportunity to catch a glimpse of the companies origins in lead sheet production dating back to the 1850’s.
Sand casting lead sheet was a process used by the Romans and Medieval metal workers and is still used today by specialist manufacturers, typically used for conservation work.
The process begins by melting recycled lead up to a temperature of 450ºC and removing any impurities with a ladle. The molten lead is allowed to cool to around 350ºC and then poured over a smooth rectangular sand bed.
A spreader is used to push the molten lead down the bed to achieve the desired thickness of sheet. Once poured the lead cools quickly and can be cut to the required size.
