Loam molding

Last updated

Loam molding was formerly used for making cast iron or bronze cannon and is still used for casting large bells.

Loam (pronounced 'low-m') is a mixture of sand and clay with water, sometimes with horse dung (valuable for its straw content), [1] [2] animal hair or coke. The object of including dung or hair was to make the mould permeable and allow gas (such as steam) to escape during casting. [3]

The mold for a cylindrically symmetrical object, such as a cannon, is built up in stages around a spindle, to which is fixed a strickle board with the shape of the eventual casting. The mold also has provision for the casting of a gunhead, beyond the muzzle of the cannon, into which slag can float during casting. If the object is to be hollow, a straw rope is wound around the spindle and covered in a friable material to the dimensions of the exterior of the cannon, the strickle board being turned on the spindle to ensure it is cylindrical. Decorative elements and models of the trunnions are then attached. This is then covered in a thick layer of loam. The mold is then fired. After this the straw rope is then pulled out with the rest of the material used to form the shape of the cannon.

The mould is then mounted vertically in a casting put in front of the furnace. If the cannon is to be cast hollow, a core is mounted in the mould. The furnace was then tapped and metal run into the mold. The mold is then broken off the casting. The gunhead is cut off, and the bore of the cannon reamed out using a boring mill.

The process for the cylinder for a steam engine would be similar. The process for casting a bell is of the same nature, but the procedure is necessarily different. [4]

Related Research Articles

<span class="mw-page-title-main">Metal casting</span> Pouring liquid metal into a mold

In metalworking and jewelry making, casting is a process in which a liquid metal is delivered into a mold that contains a negative impression of the intended shape. The metal is poured into the mold through a hollow channel called a sprue. The metal and mold are then cooled, and the metal part is extracted. Casting is most often used for making complex shapes that would be difficult or uneconomical to make by other methods.

<span class="mw-page-title-main">Pig iron</span> Iron alloy

Pig iron, also known as crude iron, is an intermediate good used by the iron industry in the production of steel. It is developed by smelting iron ore in a blast furnace. Pig iron has a high carbon content, typically 3.8–4.7%, along with silica and other dross, which makes it brittle and not useful directly as a material except for limited applications.

<span class="mw-page-title-main">Cast iron</span> Iron-carbon alloys with a carbon content more than 2% and silicon content between 1 and 3%

Cast iron is a class of iron–carbon alloys with a carbon content of more than 2% and silicon content around 1–3%. Its usefulness derives from its relatively low melting temperature. The alloying elements determine the form in which its carbon appears: white cast iron has its carbon combined into an iron carbide named cementite, which is very hard, but brittle, as it allows cracks to pass straight through; grey cast iron has graphite flakes which deflect a passing crack and initiate countless new cracks as the material breaks, and ductile cast iron has spherical graphite "nodules" which stop the crack from further progressing.

<span class="mw-page-title-main">John Wilkinson (industrialist)</span> English industrialist

John "Iron-Mad" Wilkinson was an English industrialist who pioneered the manufacture of cast iron and the use of cast-iron goods during the Industrial Revolution. He was the inventor of a precision boring machine that could bore cast iron cylinders, such as cannon barrels and piston cylinders used in the steam engines of James Watt. His boring machine has been called the first machine tool. He also developed a blowing device for blast furnaces that allowed higher temperatures, increasing their efficiency, and helped sponsor the first iron bridge in Coalbrookdale. He is notable for his method of cannon boring, his techniques at casting iron and his work with the government of France to establish a cannon foundry.

<span class="mw-page-title-main">Molding (process)</span> Shaping a liquid or plastic material by making it conform to a more rigid mold

Moulding or Molding see spelling differences) is the process of manufacturing by shaping liquid or pliable raw material using a rigid frame called a mold or matrix. This itself may have been made using a pattern or model of the final object.

<span class="mw-page-title-main">Industrial processes</span> Process of producing goods

Industrial processes are procedures involving chemical, physical, electrical, or mechanical steps to aid in the manufacturing of an item or items, usually carried out on a very large scale. Industrial processes are the key components of heavy industry.

<span class="mw-page-title-main">Lost-wax casting</span> Process by which a duplicate metal sculpture is cast from an original sculpture

Lost-wax casting – also called investment casting, precision casting, or cire perdue – is the process by which a duplicate sculpture is cast from an original sculpture. Intricate works can be achieved by this method.

<span class="mw-page-title-main">Sand casting</span> Metal casting process using sand as the mold material

Sand casting, also known as sand molded casting, is a metal casting process characterized by using sand — known as casting sand — as the mold material. The term "sand casting" can also refer to an object produced via the sand casting process. Sand castings are produced in specialized factories called foundries. In 2003, over 60% of all metal castings were produced via sand casting.

<span class="mw-page-title-main">Foundry</span> Factory that produces metal castings

A foundry is a factory that produces metal castings. Metals are cast into shapes by melting them into a liquid, pouring the metal into a mold, and removing the mold material after the metal has solidified as it cools. The most common metals processed are aluminum and cast iron. However, other metals, such as bronze, brass, steel, magnesium, and zinc, are also used to produce castings in foundries. In this process, parts of desired shapes and sizes can be formed.

This article is a list of terms commonly used in the practice of metalworking – the science, art, industry, and craft of shaping metal.

Bellfounding is the casting and tuning of large bronze bells in a foundry for use such as in churches, clock towers and public buildings, either to signify the time or an event, or as a musical carillon or chime. Large bells are made by casting bell metal in moulds designed for their intended musical pitches. Further fine tuning is then performed using a lathe to shave metal from the bell to produce a distinctive bell tone by sounding the correct musical harmonics.

<span class="mw-page-title-main">Lifecasting</span> Process of creating a three-dimensional copy of a living human body

Lifecasting is the process of creating a three-dimensional copy of a living human body, through the use of molding and casting techniques. In rare cases lifecasting is also practiced on living animals. The most common lifecasts are 3D hand casting, casting of torsoes, pregnant bellies, faces, and genitalia and it is possible for an experienced lifecasting practitioner to copy any part of the body. Lifecasting is usually limited to a section of the body at a time, but full-body lifecasts are achievable too. Compared with other three-dimensional representations of humans, the standout feature of lifecasts is their high level of realism and detail. Lifecasts can replicate details as small as fingerprints and pores.

<span class="mw-page-title-main">Pattern (casting)</span>

In casting, a pattern is a replica of the object to be cast, used to form the sand mould cavity into which molten metal is poured during the casting process. Once the pattern has been used to form the sand mould cavity, the pattern is then removed, Molten metal is then poured into the sand mould cavity to produce the casting. The pattern is non consumable and can be reused to produce further sand moulds almost indefinitely.

<span class="mw-page-title-main">Glass casting</span> Process for making objects from molten glass

Glass casting is the process in which glass objects are cast by directing molten glass into a mould where it solidifies. The technique has been used since the 15th century BCE in both Ancient Egypt and Mesopotamia. Modern cast glass is formed by a variety of processes such as kiln casting or casting into sand, graphite or metal moulds.

<span class="mw-page-title-main">Cupola furnace</span> Small blast furnace for melting scrap iron without reduction reactions

A cupola or cupola furnace is a melting device used in foundries that can be used to melt cast iron, Ni-resist iron and some bronzes. The cupola can be made almost any practical size. The size of a cupola is expressed in diameters and can range from 1.5 to 13 feet. The overall shape is cylindrical and the equipment is arranged vertically, usually supported by four legs. The overall look is similar to a large smokestack.

<span class="mw-page-title-main">Roman metallurgy</span> Production and usage of metal in ancient Rome

Metals and metal working had been known to the people of modern Italy since the Bronze Age. By 53 BC, Rome had expanded to control an immense expanse of the Mediterranean. This included Italy and its islands, Spain, Macedonia, Africa, Asia Minor, Syria and Greece; by the end of the Emperor Trajan's reign, the Roman Empire had grown further to encompass parts of Britain, Egypt, all of modern Germany west of the Rhine, Dacia, Noricum, Judea, Armenia, Illyria, and Thrace. As the empire grew, so did its need for metals.

<span class="mw-page-title-main">Casting</span> Manufacturing process in which a liquid is poured into a mold to solidify

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 broken out of the mold to complete the process. Casting materials are usually metals or various time setting materials that cure after mixing two or more components together; examples are epoxy, concrete, plaster and clay. Casting is most often used for making complex shapes that would be otherwise difficult or uneconomical to make by other methods. Heavy equipment like machine tool beds, ships' propellers, etc. can be cast easily in the required size, rather than fabricating by joining several small pieces. Casting is a 7,000-year-old process. The oldest surviving casting is a copper frog from 3200 BC.

Plano-convex ingots are lumps of metal with a flat or slightly concave top and a convex base. They are sometimes, misleadingly, referred to as bun ingots which imply the opposite concavity. They are most often made of copper, although other materials such as copper alloy, lead and tin are used. The first examples known were from the Near East during the 3rd and 2nd Millennia BC. By the end of the Bronze Age they were found throughout Europe and in Western and South Asia. Similar ingot forms continued in use during later Roman and Medieval periods.

<span class="mw-page-title-main">Centrifugal casting (industrial)</span> Casting technique that is typically used to cast thin-walled cylinders

Centrifugal casting or rotocasting is a casting technique that is typically used to cast thin-walled cylinders. It is typically used to cast materials such as metals, glass, and concrete. A high quality is attainable by control of metallurgy and crystal structure. Unlike most other casting techniques, centrifugal casting is chiefly used to manufacture rotationally symmetric stock materials in standard sizes for further machining, rather than shaped parts tailored to a particular end-use.

<span class="mw-page-title-main">Lute (material)</span>

Lute was a substance used to seal and affix apparatus employed in chemistry and alchemy, and to protect component vessels against heat damage by fire; it was also used to line furnaces. Lutation was thus the act of "cementing vessels with lute".

References

  1. John Campbell, Complete Casting Handbook: Metal Casting Processes, Techniques and Design (2011), 929.
  2. W.K.V. Gale, The iron and steel industry: a dictionary of terms (1971), 126.
  3. R.F. Tylecote, 'Inron in the industrial revolution' in L. Day and R.F. Tylecote, Industrial Revolution in metals (Institute of Materials, London, 1991), 243-4.
  4. Taylors of Loughborough, bellfounders.