Large rocks inside the drum crush the graphite and clay into a fine powder. ... the dried sludge into another fine powder, and water is blended in again to make a soft paste. ... The same machine cuts apart each slat into eight separate pencils.
Jun 27, 2005 ... A vacuum pump may be used to remove air from the clay to make it ... scraper to a platform where the clay powder was dumped into small, ... Before the invention of steamdriven machines, bricks were moulded by hand.