Thwaite Watermill at 30

Thwaite Watermill is one of the nine sites that make up Leeds Museums and Galleries. Hidden on a tranquil island between the River Aire and the Aire and Calder Navigation, it houses one of the last examples of a working water-powered mill in Britain. This year marks the 30^th anniversary of the museum opening to the public – a perfect opportunity to share some of its fascinating history with you!

Thwaite Watermill today

A Fulling Mill

Industry first began on the site’s location in 1641 when a weir was built across the natural bend in the River Aire. This held some water back, creating a pool which could be diverted into a mill and turn waterwheels to power machinery. The first mill constructed was used for fulling, a textiles process which cleaned and matted together the fibres of newly woven cloth by pounding it in human urine and then Fuller’s Earth (a clay-like substance).

Once fulled and stretched out, cloth was suitable for dyeing and tailoring.

A diagram explaining the fulling process

Reconstruction

By 1823 the mill had become dilapidated. The Aire and Calder Navigation Company decided to demolish and rebuild it entirely, along with a workshop, warehouse, stables, workers’ cottages (known as Dandy Row) and a mill tenants’ house. Inside the mill two water wheels were constructed from cast iron and elm, measuring 5.6 metres in diameter and capable of rotating at 7.7 miles an hour. Both wheels remain today, and at least one still turns to operate the connecting cogs, shafts and pulleys which originally powered the machinery.

One of the two water wheels in Thwaite Watermill

The Joy Family

In 1825 the first tenants of the new mill arrived: the Joy family. They established ‘Edward Joy and Sons Ltd’, a company which produced lighting and lubricating ‘Filtrate’ oils by crushing rapeseed and other seeds. Much of this oil was sold to railways for use on steam engines, apparently including George Stephenson’s famous “Rocket”, an award winning locomotive. The Joys also crushed exotic wood from places such as South America to produce colour dyes for textile manufacture. By 1845 the family had left Thwaite, but their company continued successfully for many years.

A Filtrate Oil can, produced by the Joy family at Thwaite Watermill

The Horn Family

There was at least one other tenancy at Thwaite in the two decades after the Joys left, but by the 1870s the mill had again fallen into disrepair. This time it was the Horn Family who restored and rejuvenated the site, arriving in 1872 and installing stone-crushing equipment. The Horns continued to run the mill until its closure in 1976.

William Horn, mill owner, on a boat in the mill pond, c.1900

For the first 50 years, their main outputs were crushed chalk (or “whiting”), used in paint and pharmaceutical products, and china stone and flint slurry, used by local potteries to make glaze, the shiny surface on ceramics. Perhaps their most famous product, however, was putty. Putty production began in 1923 as a way of utilising surplus whiting.  The thick playdough-like substance was (and often still is) used for glazing: sealing window panes into their frames. What began as a way of using up a waste product quickly became the Horns’ most successful venture, and by 1950 they were producing around 800 tons annually. By the 1960s putty was their sole output.

Putty tins stacked in the mill’s Putty Packing Room

Putty being loaded onto a Horn lorry from the warehouse

It was during the early 1940s that Horn putty experienced its greatest demand, however. Between September 1940 and May 1941, Britain experienced a period of intense German bombing known as the Blitz, during which 43,500 people were killed and many thousands of buildings were destroyed or badly damaged. Thankfully, Thwaite Watermill itself was never bombed, which is lucky considering its industrial status and location between two waterways, easy for German pilots to spot from above. By manufacturing putty it proved vital in repairing the windows of other damaged buildings, perhaps helping to uphold morale in war-torn communities. Demand from London was such that, even with the mill operating 24 hours a day, 7 days a week, the Horns struggled to keep up. Unexpectedly therefore, the Second World War may be seen as beneficial for Thwaite!

Destruction in London caused by the Blitz

Decline and Flood

As time progressed towards the later 20^th century, the success of Horn putty began to wane. The Horns’ production methods gradually became outdated and they were less able to compete with newer manufacturers. Moreover, the growing popularity of uPVC (unplasticised polyvinyl chloride) window frames and double glazing significantly reduced demand, as they are not sealed using linseed oil putty.

Even so, the end of production was not caused by a gradual decline in orders. The mill’s closure was abrupt and unplanned, forced by an unexpected disaster. On the night of the 29^th January 1975, heavy rain caused the river to breach the weir. The structure collapsed, which meant water was no longer diverted into the mill and the wheels stopped turning. Without this source of power the putty pans, which mixed the ingredients to make putty, could not function and the mill was unable to produce its only remaining output. Repairing the weir would have been too costly and, with demand for putty already declining, it was deemed sensible to close the mill. Remaining orders were completed using power from a Petter diesel engine and operations finally ceased in 1976, bringing an end to five generations of mill management by the Horn family.

The Petter Engine, used to complete final orders before the mill closed in 1976

Restoration and Museum Opening

Fortunately, the mill was not left empty for long. In 1978 the Thwaite Mills Society formed: a group of volunteers who refused to see the site go to waste. They inaugurated a major building operation to restore the mill and its surroundings. The weir was rebuilt in concrete and steel and the machinery, buildings and water wheels were repaired and refurbished. In 1990 the site opened as a museum, now run by Leeds City Council.

The rebuilding of the weir, c. 1985

Today, visitors can experience the sights, sounds and smells of the virtually unchanged stone crushing works and explore most of the original buildings. Do come and see our Thwaite at Thirty exhibition when it opens later this year and help us to celebrate nearly 400 years of fascinating history!

Happy 30th Anniversary to Thwaite Watermill!

By Chloe Fowler, Visitor Assistant at Thwaite Watermill