slicker

A slicker is a hand-held steel tool with a smooth, curved working surface used to compress and smooth the sand or loam walls of a mould cavity after pattern withdrawal. The tool typically has a blade 2 to 4 inches wide with a gentle, almost imperceptible curve along its length, mounted on a wooden or metal handle. Its sole purpose is to eliminate irregularities, tool marks, and slight undercuts left behind by the pattern, producing a surface finish smooth enough to accept metal without defects.

Slickers come in several profile variants. The most common is the flat or slightly domed slicker, used for general smoothing of vertical or gently sloping surfaces. Specialized versions include the corner slicker, which has a rounded nose for working into acute angles between vertical and horizontal walls, and the hollow slicker, featuring a concave working surface for smoothing the insides of cylindrical or spherical cavities. Each variant costs between 8 and 25 dollars depending on material and size.

A rough mould surface causes metal to flow unevenly during pouring, producing surface defects called misruns or cold shuts where the metal fails to fill the cavity completely. More problematically, rough surfaces increase friction on the pattern during withdrawal, raising the risk of the pattern sticking in the mould and requiring forceful extraction that damages the cavity. A well-slickered surface allows cleaner pattern withdrawal and smoother metal fill, reducing scrap and rework.

The slicker is applied in long, even strokes along the mould surface, often with light water or specially formulated mould dressing applied to reduce friction and seal the sand grains. Excessive pressure or repeated passes can compact the mould face so much it becomes glossy and prone to burning, where molten metal oxidizes into the sand and fuses to the casting surface. The trade skill lies in knowing when the surface is ready and when further work does more harm than good.

Slickers are a foundry hand tool, used in both ferrous and non-ferrous casting of small to medium work. In production foundries where moulds are made by machine, slickers see less use; in jobbing shops and artistic casting, they remain essential. The name is descriptive: the tool makes surfaces slicker, smoother, and less resistant to withdrawal and flow.