<Tr> <Td> </Td> <Td> This section needs expansion . You can help by adding to it . (November 2012) </Td> </Tr> <P> In 1949, Edward Seymour, of Sycamore, IL, added paint to existing spray can technology at his wife Bonnie's suggestion . It was initially designed to demonstrate an aluminum paint he developed . </P> <P> Most aerosol paints also have a metal, glass or plastic ball called a pea inside of the can, which is used to mix the paint when the can is shaken . </P> <P> Acrylic - based craft primers and vinyl dye can be used on plastics like models or miniatures . </P>

Why is there a ball inside spray paint