The Science of Sandcast Lead: CEL

The Science of Sandcast Lead: CEL

Cambridgeshire-based CEL, are the countries leading manufacturer of sandcast sheet lead. How this valuable and malleable material is formed is fascinating and the basic process hasn’t changed since Roman times.

Seeing several tonnes of molten lead running like liquid silver down a ‘sand-table’ is an unbelievable sight yet it is not a 21st century process. The Roman’s cast sheet lead much the same way over 2000 years ago. So the actual basic way of producing quality sandcast lead, that is malleable and easy to work, hasn’t changed much in all that time but Whittlesey, Cambridgeshire-based CEL have turned it into a more mechanised, safer and faster process, while keeping the integrity of the original methods of the product.

It may be faster but the CEL, which stood for Carl Edwards Lead work before the company developed into its main contractor role, casting team use a high degree of eye and hand skills and experience to produce gleaming sheets of freshly cast lead, which is usually made to order in thicknesses from Code 5 to 10, that is then shipped to customers throughout the country and Europe.

CEL is one of just several companies that can cast sheet lead in the traditional way using a what to a layman’s eye appears to be a production line process: a giant cauldron that melts scrap and lead offcuts, a hopper that spills the lead, a long sand covered table set at a slight downward gradient and a clever multi-task machine that runs over the table on rails.

The mechanised parts of the process includes the pump, which transfers the molten lead to a hopper, the hopper which is tipped up hydraulically, and the machine on rails that rotivates the sand after each cast, tamps it down and carries blades that can be set to cut the new sheet lead. Everything else is done by hand.

The cauldron seems to have an insatiable appetite for lead, which the two man casting team continually feed. While the lead melts the team set about preparing the casting table, which is covered with an even bed of special soft sand. The overhead machine then travels the track tamping the sand down, then the skills of the two-man team kick in – they check over the levels ensuring there all no hollows or hills.

Now the hard works starts as they use large square floats, much the same a plasterer uses, but larger, to give the sand a super-smooth finish. Again any dips or hard spots of sand are removed before the whole thing is covered with a fine spray of water. Molten lead is pumped to the hopper, the hopper tips and spreads the sea of lead across the table and it runs down the slope just like the tide coming up a beach. Once cooled the men cut the lead into exact sizes to meet the client’s requirements and the whole process starts again, any lead off-cuts going back into the cauldron.

Says Carl Edwards, CEL’s managing director: “I wanted to build a new machine based on the traditional working practices that would cast using modern technology so I set about designing one based on previous experiences but even then it took six months to set up the table and getting it to produce sheet lead to the standard I demanded. “We are able to manufacture sizes and codes of lead to suit customer’s requirements and are now the biggest exporter of sandcast lead in Europe. We have worked on some very big contracts, including Reims cathedral and Paris’s Notre Dame in France.”

Carl originally trained as a plumber, and one part of his apprenticeship included lead work, which intrigued him. “I quickly realised this was the work I wanted to do so once I finished my training I got a job at a roofing company, where I fitted flashings and did sheet work. “Then I moved to a specialist lead-working company and one of my first jobs was working on Hampton Court palace, which had been seriously damaged by fire. That was a massive leap into the world of heritage restoration for me.”

In 1991 Carl set up his own business in a unit in Woodston, Peterborough, where he developed a small casting table, finally moving to a much bigger factory in Whittlesey in 1998, which allowed him to expand even further. Besides manufacturing and supplying sandcast lead, which is usually made to order, CEL are stockholders of milled lead in 3 and 6m lengths ranging from code 3 up to 8. The company also produces bespoke decorative lead rainwater goods and features and also stock a wide range of roofing sundries. The company are proud of some of the projects they have worked on, including Westminster Abbey, Castle Howard and Windsor Castle. You can’t get a better set of references than that!

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Mel Russ