Aluminum Scraper 4 SA4Aluminum Scraper 4 SA4 Used for shaping, smoothing and trimming pottery shapes. The steel scrapers (S) are made from thin flexible spring stainless steel. They are slightly heavier gauge steel, making them somewhat stiffer. The aluminum scrapers (SA) are made from a high strength aircraft alloy that is much more rigid. The rigid scrapers can also be used as a squeegee to remove excess water from pottery shapes.