Harbutt invented Plasticine around 1897 as a non-drying modelling clay for use by his students. In 1899, Harbutt was awarded a trade mark, and in 1900, a factory was set up at nearby Bathampton to manufacture the product for commercial sale. Harbutt travelled widely to promote the product, and his theories about the teaching of art by allowing children free expression.
He and Bessie had seven children, six of whom survived infancy and worked in the family business. The Harbutt company, owned and run by Harbutt's descendants, continued to manufacture Plasticine in Bathampton until 1983.
Death
He died of pneumonia while on a trip to New York City in 1921. He is buried near the old factory in the churchyard at St Nicholas’ Church.
In 2009, his hometown of North Shields attempted to commemorate his legacy by commissioning some street furniture to resemble plasticine shapes and colour, made out of concrete.[9] Unfortunately these had to be removed shortly after installation due to complaints from the public,[10][11] as the street furniture retained pools of water in the seats after rain rendering them unusable or the user getting wet. In addition, they were not comfortable or practical and very problematic for elderly or infirm members of the public to get in to and up from. The 'plasticine' chairs were relocated throughout the region to less commercial areas including to the grounds of a local sixth form college and repainted from the plain plasticine colours to various colour schemes and designs. These remain in place (if rarely used or occupied). Traditional metal street furniture replaced the 'plasticine' furniture in the town centre of his birthplace.