"Puddlers" were common in 19th century census records in steel making areas. As Rod says, puddling is related to iron making. This method of making smelting iron, patented in 1784, which iron made molten in a reverberatory or air furnace using ordinary coal was stirred or "puddled" to remove impurities. In early puddling furnaces, men (the puddlers), stirred the iron using long rods. Hot and dangerous work - they must have been pretty tough in those days! Puddled iron is also known as wrought iron. The process was largely superseded when mass production of cheap steel started.