Pot metal (or monkey metal) is an
alloy
An alloy is a mixture of chemical elements of which in most cases at least one is a metal, metallic element, although it is also sometimes used for mixtures of elements; herein only metallic alloys are described. Metallic alloys often have prop ...
of low-melting point metals that manufacturers use to make fast, inexpensive castings. The term "pot metal" came about because of automobile factories' practice in the early 20th century of gathering up non-ferrous metal scraps from the manufacturing processes and melting them in one pot to form into cast products. Small amounts of iron often made it into the castings but never in significant quantity because too much iron would raise the melting point too high for simple casting operations.
In
stained glass
Stained glass refers to coloured glass as a material or art and architectural works created from it. Although it is traditionally made in flat panels and used as windows, the creations of modern stained glass artists also include three-dimensio ...
, "pot metal" or
pot metal glass refers to glass coloured with metal oxides while it is molten (in a pot), as opposed to other methods of colouring glass in sheet form.
Metallurgy
There is no metallurgical standard for pot metal. Common metals in pot metal include
zinc
Zinc is a chemical element; it has symbol Zn and atomic number 30. It is a slightly brittle metal at room temperature and has a shiny-greyish appearance when oxidation is removed. It is the first element in group 12 (IIB) of the periodic tabl ...
,
lead
Lead () is a chemical element; it has Chemical symbol, symbol Pb (from Latin ) and atomic number 82. It is a Heavy metal (elements), heavy metal that is density, denser than most common materials. Lead is Mohs scale, soft and Ductility, malleabl ...
,
copper
Copper is a chemical element; it has symbol Cu (from Latin ) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orang ...
,
tin
Tin is a chemical element; it has symbol Sn () and atomic number 50. A silvery-colored metal, tin is soft enough to be cut with little force, and a bar of tin can be bent by hand with little effort. When bent, a bar of tin makes a sound, the ...
,
magnesium
Magnesium is a chemical element; it has Symbol (chemistry), symbol Mg and atomic number 12. It is a shiny gray metal having a low density, low melting point and high chemical reactivity. Like the other alkaline earth metals (group 2 ...
,
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 ...
,
iron
Iron is a chemical element; it has symbol Fe () and atomic number 26. It is a metal that belongs to the first transition series and group 8 of the periodic table. It is, by mass, the most common element on Earth, forming much of Earth's o ...
, and
cadmium
Cadmium is a chemical element; it has chemical symbol, symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12 element, group 12, zinc and mercury (element), mercury. Like z ...
. The primary advantage of pot metal is that it is quick and easy to cast. Because of its low melting temperature, it requires no sophisticated foundry equipment or specialized molds. Manufacturers sometimes use it to experiment with molds and ideas (e.g.,
prototype
A prototype is an early sample, model, or release of a product built to test a concept or process. It is a term used in a variety of contexts, including semantics, design, electronics, and Software prototyping, software programming. A prototype ...
s) before casting final products in a higher quality alloy.
Depending on the exact metals "thrown into the pot", pot metal can become unstable over time, as it has a tendency to bend, distort, crack, shatter, and pit with age. The low boiling point of zinc and fast cooling of newly cast parts often trap air bubbles within the cast part, weakening it. Many components common in pot metal are susceptible to corrosion from airborne acids and other contaminants, and internal corrosion of the metal often causes decorative plating to flake off. Pot metal is not easily glued,
soldered, or
welded.
In the late nineteenth century, ''pot metal'' referred specifically to a copper alloy that was primarily alloyed with lead. Mixtures of 67% copper with 29% lead and 4% antimony and another one of 80% copper with 20% lead were common formulations.
The primary component of pot metal is zinc, but often the caster adds other metals to the mix to strengthen the cast part, improve flow of the molten metal, or to reduce cost. With a low melting point of 420 °C (786 °F), zinc is often alloyed with other metals including lead, tin, aluminium, and copper.
Uses

Pot metal is generally used for parts that are not subject to high stresses or
torque
In physics and mechanics, torque is the rotational analogue of linear force. It is also referred to as the moment of force (also abbreviated to moment). The symbol for torque is typically \boldsymbol\tau, the lowercase Greek letter ''tau''. Wh ...
. Items created from pot metal include toys,
furniture fittings, tool parts, electronics components, automotive parts, inexpensive jewelry and
improvised weaponry.. Pot metal was commonly used to manufacture gramophone parts in the late 1920s and 1930s, with notable examples being the back covers on some
His Master's Voice
His Master's Voice is an entertainment trademark featuring a dog named Nipper, curiously peering into the horn of a wind-up gramophone. Painted by Francis Barraud in 1898, the image has since become a global symbol used across consumer elect ...
no.4 soundboxes and
His Master's Voice
His Master's Voice is an entertainment trademark featuring a dog named Nipper, curiously peering into the horn of a wind-up gramophone. Painted by Francis Barraud in 1898, the image has since become a global symbol used across consumer elect ...
no.5 soundboxes. It was also used to make loudspeaker transducers used with early radio horn speakers before cone speakers were developed. It is also used in inexpensive electric guitars and other budget-priced musical instruments.
See also
*
Babbitt (alloy)
Babbitt metal or bearing metal is any of several alloys used for the bearing surface in a plain bearing.
The original Babbitt alloy was invented in 1839 by Isaac Babbitt in Taunton, Massachusetts, United States. He disclosed one of his alloy rec ...
*
Pewter
Pewter () is a malleable metal alloy consisting of tin (85–99%), antimony (approximately 5–10%), copper (2%), bismuth, and sometimes silver. In the past, it was an alloy of tin and lead, but most modern pewter, in order to prevent lead poi ...
*
White metal
*
Zamak
ZAMAK (or Zamac, formerly trademarked as MAZAK) is an eclectic family of alloys with a base metal of zinc and alloying elements of aluminium, magnesium, and copper.
Zamak alloys are part of the zinc aluminium alloy family; they are distinguished ...
*
Zinc aluminium
*
Zinc pest
Zinc pest (from German ''Zinkpest'' "zinc plague"), also known as zinc rot, mazak rot and zamak rot, is a destructive, intercrystalline corrosion process of zinc alloys containing lead impurities. Prepared under the direction of the ASM Interna ...
References
{{Reflist
Copper alloys
Zinc alloys