Editing Forge (section)

== Types ==
{{unreferenced section|date=August 2012}}

=== Coal/coke/charcoal forge ===
[[File:Coal-forge-diagram.svg|thumb|Bottom blast coal forge]]

A forge typically uses [[bituminous coal]], industrial [[Coke (fuel)|coke]] or [[charcoal]] as the fuel to heat metal. The designs of these forges have varied over time, but whether the fuel is [[coal]], [[Coke (fuel)|coke]] or [[charcoal]] the basic design has remained the same.<ref>{{cite web |url=http://www.anvilfire.com/FAQs/the_forge.php |title=The Blacksmith Forge Part 1 the Pit Forge : Anvilfire.com article |access-date=2016-07-31 |url-status=live |archive-url=https://web.archive.org/web/20161007030701/http://www.anvilfire.com/FAQs/the_forge.php |archive-date=2016-10-07 }}</ref>

A forge of this type is essentially a hearth or [[fireplace]] designed to allow a fire to be controlled such that metal introduced to the fire may be brought to a malleable state or to bring about other [[Metallurgy|metallurgical]] effects ([[Hardening (metallurgy)|hardening]], [[Annealing (metallurgy)|annealing]], and [[Tempering (metallurgy)|tempering]] as examples). The forge fire in this type of forge is controlled in three ways:{{citation needed|date=August 2012}} amount of air, the volume of fuel, and shape of the fuel/fire.

[[File:Schmiedefeuer 2.jpg|thumb|A forge fire for [[hot working]] of metal]]

Over thousands of years of forging, these devices have evolved in one form or another as the essential features of this type of forge:<ref>{{Cite journal|last=Light|first=John D.|date=July 1987|title=Blacksmithing Technology and Forge Construction|jstor=3104997|journal=Technology and Culture|volume=28|issue=3|pages=658–665|doi=10.2307/3104997|s2cid=112819098 }}</ref>

* [[Tuyere]]—a pipe through which air can be forced into the fire
* [[Bellows]] or blower—a means for forcing air into the [[tuyere]]
* Hearth—a place where the burning fuel can be contained over or against the tuyere opening. Traditionally hearths have been constructed of mud-brick ([[adobe]]), fired brick, stone, or later, constructed of iron.

During operation, fuel is placed in or on the hearth and ignited. A source of moving air, such as a [[Mechanical fan|fan]] or bellows, introduces additional air into the fire through the tuyere. With additional air, the fire consumes fuel faster and burns hotter (and cleaner - smoke can be thought of as escaped potential fuel).

A [[blacksmith]] balances the fuel and air in the fire to suit particular kinds of work. Often this involves adjusting and maintaining the shape of the fire.

In a typical coal forge, a firepot will be centred in a flat hearth. The tuyere will enter the firepot at the bottom. In operation, the hot core of the fire will be a ball of burning coke in and above the firepot. The heart of the fire will be surrounded by a layer of hot but not burning coke. Around the unburnt coke will be a transitional layer of coal being transformed into coke by the heat of the fire. Surrounding all is a ring or horseshoe-shaped layer of raw coal, usually kept damp and tightly packed to maintain the shape of the fire's heart and to keep the coal from burning directly so that it "cooks" into coke first.

If a larger fire is necessary, the smith increases the air flowing into the fire as well as feeding and deepening the coke heart. The smith can also adjust the length and width of the fire in such a forge to accommodate different shapes of work.

The major variation from the forge and fire just described is a '[[backdraft]]' where there is no fire pot, and the tuyere enters the hearth horizontally from the back wall.

Coke and charcoal may be burned in the same forges that use coal, but since there is no need to convert the raw fuel at the heart of the fire (as with coal), the fire is handled differently.

Individual smiths and specialized applications have fostered the development of a variety of forges of this type, from the coal forge described above to simpler constructions amounting to a hole in the ground with a pipe leading into it.

=== Gas forge ===
A gas forge typically uses [[propane]] or [[natural gas]] as the fuel. One common, efficient design uses a cylindrical forge chamber and a burner tube mounted at a right angle to the body. The chamber is typically lined with [[refractory]] materials such as a hard castable refractory [[ceramic]] or a soft ceramic thermal blanket (ex: [[Mineral wool|Kaowool]]). The burner mixes fuel and air which are ignited at the tip, which protrudes a short way into the chamber lining. The air pressure, and therefore heat, can be increased with a mechanical blower or by taking advantage of the [[Venturi effect]].

Gas forges vary in size and construction, from large forges using a big burner with a blower or several atmospheric burners to forges built out of a [[coffee]] can utilizing a cheap, simple [[propane torch]]. A small forge can even be carved out of a single soft [[firebrick]].

The primary advantage of a gas forge is the ease of use, particularly for a novice. A gas forge is simple to operate compared to coal forges, and the fire produced is clean and consistent. They are less versatile, as the fire cannot be reshaped to accommodate large or unusually shaped pieces. It is also difficult to heat a small section of a piece. A common misconception is that gas forges cannot produce enough heat to enable forge-[[welding]], but a well-designed gas forge is hot enough for any task.

=== Finery forge ===
{{main|Finery forge}}
A [[finery forge]] is a water-powered mill where [[pig iron]] is refined into [[wrought iron]].