He boarded with the Saunders family from England at Oxford Street, Paddington, and on 17 May 1888 married their daughter Emma at the local district registrar's office.
The largest glassmaking establishment in Sydney, with a high reputation, the firm created the chapel windows for St Scholastica's Convent, Glebe, in the early 1930s.
During the 1920s John Ashwin & Co. produced the stained glass for the impressive, vaulted ceiling of what became the Commonwealth Savings Bank in Martin Place to designs by Radecki.
These had an Australian character, illustrating 'the basic sources of wealth': sheep and cattle grazing, agriculture, mining, shipping and building; stockmen, carpenters, gold panning, farming and wharf labourers were shown alongside a typical banking scene.
A window for the reading room of the Mitchell Library, signed 'John Radecki, Sydney 1941', depicted the printer William Caxton with the first book printed in English.