Our Old Bridge is a striking example of heritage engineering, so when it comes to the refurbishment only the best will do.
Readers will already know we have plans to upgrade the crossing’s ornate lighting, and we’ve introduced the specialist lighting firm responsible for this work; now we’re taking a look at the company which is creating the lighting columns themselves.
Hargreaves Foundry is based in Halifax, West Yorkshire, and has been casting iron since 1881. The firm is a long-established supplier of castings to the engineering sector, as well as for heritage, conservation and modern projects and work for internationally-renowned architects and artists. This includes casting 394 columns for a modern building by David Chipperfield; restoration work on the Palace of Westminster and the Elizabeth Tower (commonly known as Big Ben); and the casting of fine art sculptures for Sir Antony Gormley.
For the Rochester Bridges Refurbishment Project, the foundry has been contracted to reproduce cast iron lighting columns for our Old Bridge, based on prototypes of the original Victorian designs. The process involves pattern making, moulding, casting and finishing.
Pattern making is the production of a precise reproduction of the original casting, using wood and resin. This is highly-skilled work and serves as a tool for the foundry. Skilled moulders then use the pattern to make a sand mould, into which molten iron is poured. Once the metal has cooled, the casting is broken out of the mould and fettled. This is a finishing process that includes grinding and shot blasting. All of the iron used at Hargreaves Foundry is recycled, and the sand from the moulds is re-used.
The work is ongoing, with updates occasionally appearing on the Hargreaves Foundry Twitter feed.