Sandguss

Sandguss, or sand casting, is a metal casting process in which a mold cavity is formed by packing and shaping sand around a pattern. The pattern is removed, leaving a hollow mold into which molten metal is poured to produce a solid metal part. The method supports a wide range of sizes and alloys and remains one of the most economical ways to produce metal components, especially in low to medium production volumes.

Molds commonly use green sand, a mixture of silica sand, clay binder, and moisture, but dry sand and resin-bonded sands are also used. The pattern can be made of wood, metal, or polymer, and cores made from sand or other materials create internal passages in the finished part. The mold is typically divided into a cope (top) and a drag (bottom) portion, with a gating system that directs the flow of metal into the cavity.

Typical steps include pattern making, mold packing and ramming, core placement, mold assembly, and pouring. After pouring, the metal cools and solidifies before the mold is broken away in the shakeout. Finishing operations such as trimming, machining, and heat treatment may follow to meet dimensional and surface specifications.

Sandguss is versatile and cost-effective for ferrous and nonferrous alloys, including gray iron, ductile iron, steel, aluminum, bronze, and brass. It can produce complex geometries and large parts but generally yields rougher surface finishes and looser tolerances than more expensive processes. Defects such as porosity, misruns, or cold shuts can occur and are mitigated by process controls and post-processing.

Historically one of the oldest metal forming methods, sand casting has remained essential for prototypes, custom parts, and large or irregular shapes. Today it supports industries ranging from automotive and machinery to art and sculpture, where its flexibility and relatively low tooling cost are valued.