S1
Kemper S1 · 117 mm (4 5/8 in) half-moon with one pointed corner · Steel Scraper · Holds a straighter line than polymer · Levels and smooths
$0
A flexible sheet steel scraper for levelling and smoothing a surface that a polymer rib would flex away from. S1 is 117 mm (4 5/8 in), a half-moon with one pointed corner.
S1 is a steel scraper. It is 117 mm (4 5/8 in), a half-moon with one pointed corner. Steel holds its line where a polymer rib gives at the moment it meets resistance, so a scraper is the tool that actually gets a wall or a slab flat rather than merely smooth. Flex it between finger and thumb and it will follow a gentle curve; hold it stiff and it planes. Serrated versions exist in the same series if you want to score rather than level.
