 Shortly after completing his apprenticeship, he set himself up in Dartford, with the support of John Hall, making moulds for paper works, for at that time all paper making was done by hand.In 1798 he married Mary Brame, daughter of Peter Brame, a neighbouring land owner and market gardener, and a prominent supporter of the Methodist movement.By doing so Donkin became brother in law to John Hall, who had married Mary's elder sister Sarah in 1791.