A flask is a type of tooling used to contain a

mold A mold () or mould () is one of the structures that certain fungus, fungi can form. The dust-like, colored appearance of molds is due to the formation of Spore#Fungi, spores containing Secondary metabolite#Fungal secondary metabolites, fungal ...

metal casting In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold (usually by a crucible) that contains a negative impression (i.e., a three-dimensional negative image) of the intended shape. The metal is ...

. A flask has only sides, and no top or bottom, and forms a frame around the mold, which is typically made of molding sand. The shape of a flask may be square, rectangular, round or any convenient shape. A flask can have any size so long as it is larger than the

pattern A pattern is a regularity in the world, in human-made design, or in abstract ideas. As such, the elements of a pattern repeat in a predictable manner. A geometric pattern is a kind of pattern formed of geometric shapes and typically repeated l ...

being used to make the sand mold. Flasks are commonly made of

steel Steel is an alloy of iron and carbon that demonstrates improved mechanical properties compared to the pure form of iron. Due to steel's high Young's modulus, elastic modulus, Yield (engineering), yield strength, Fracture, fracture strength a ...

aluminum Aluminium (or aluminum in North American English) is a chemical element; it has chemical symbol, symbol Al and atomic number 13. It has a density lower than that of other common metals, about one-third that of steel. Aluminium has ...

or even wood. A simple flask has two parts: the cope and the drag. More elaborate flasks may have three or even four parts.

Flask design

Flasks are often designed with bars that extend to span two opposite sides. The bars act as reinforcement to the molding sand, which is relatively weak in

tensile strength Ultimate tensile strength (also called UTS, tensile strength, TS, ultimate strength or F_\text in notation) is the maximum stress that a material can withstand while being stretched or pulled before breaking. In brittle materials, the ultimate ...

. The bars help support the sand through the molding and pouring operation. Flasks are designed with an alignment or registration feature, so that the two flasks can be aligned to one another to ensure a

casting Casting is a manufacturing process in which a liquid material is usually poured into a mold, which contains a hollow cavity of the desired shape, and then allowed to solidify. The solidified part is also known as a casting, which is ejected or ...

can be more dimensionally accurate and also in small flasks, so that they cannot be fitted together the wrong way. Flasks usually have handles or

trunnions A trunnion () is a cylindrical protrusion used as a mounting or pivoting point. First associated with cannons, they are an important military development. In mechanical engineering (see the trunnion bearing section below), it is one part of ...

designed into their construction, which assist in handling the flasks with cranes or other lifting machinery. Some flasks are used to form a mold and are removed before pouring the casting, so another mold can be made. Other flasks are designed to contain the mold through the pouring operation, and then the casting is shaken out of the mold. The flasks are then used again and again. Flasks are usually (though not always) the property of the foundry making the casting. The number of available flasks of a given size can be a limiting factor in the overall production rate.

References

*. {{Metalworking navbox, castopen Casting (manufacturing)