This is a single page in a larger project,
Introduction to the archaeometallurgy of iron
Donald B. Wagner

Casting moulds

After metal has been melted, for example in a cupola furnace, it is poured into a mould to produce a useful object. In the following we shall see a few of the many types of mould that have been used throughout history.

 Piece-moulds

We may start with piece-moulding, a technique that was used as early as the Shang period and continued in use well into the twentieth century. Here below is the ‘Iron Rhinoceros’ (铁犀) in Kaifeng, cast in 1446. The rectilinear network of ‘flash’ (impressions of mould-seams) makes it clear that the piece-mould method was used in its casting. First an exact full-scale model is made of the intended casting. This is of clay, suitably reinforced with wooden or metal supports. (We shall see below that sand mixed with some clay may also have been used in making some moulds.) When the model is dry it is plastered to a considerable thickness with wet clay; when this clay has dried to a leather-hard consistency it is cut into blocks which are carefully removed, retaining the impression of the model. These separate blocks are dried and perhaps fired for greater durability. In order to form the mould-core the model is then carefully scraped down, removing a thickness of clay corresponding to the intended thickness of the casting. The previously formed blocks are reassembled around this core to form the ‘cope’ (the outer mould). This is reinforced with a wooden framework and buttressed with earth. One or more casting inlets are made, and the molten metal is poured into the mould thus formed. When the mould is removed, the casting shows obvious seams at the joins between the individual blocks of the outer mould. In bronze castings the seams are usually removed by grinding and polishing, but in iron castings this is usually not practicable.

The close-up photograph shows what at first sight appears to be a repair to the statue, but close inspection shows that the metal is continuous through it. What we see here are traces of a repair to the mould rather than the casting. It would seem that while the cope was being built up around the core, some accident occurred which resulted in the break clearly outlined here. At this point the model had already been destroyed to make the core, and it was not possible to start again. Therefore the broken piece was replaced in position as well as it could be; the three bumps are traces of some arrangement of spikes used to hold it in place.

Below we see two of at least four cast-iron statues of the demon Wuzhiqi 巫支祁, all seemingly cast from the same model (Andersen 2001). In this case it was not necessary to use a core, destroying the model, for the statues are not hollow; they are solid iron. They are extremely heavy, and were probably used as weights for the ends of a hanging bridge.

Two statues of the demon Wuzhiqi 巫支祁, cast in 1101. Left: Held by the Museum für Asiatische Kunst, Berlin. Height 40.5 cm, weight 69 kg. Right: Held by a private American collector (Andersen 2001).

 

图一:做钟型(剖面)
1. Making the bell model (cross section)

图二:起外模(外面)
2. Applying the outer mould (exterior)

图三:外模、顶模完成(钟侧外面)
3. The completed outer mould and upper mould (side view)

图四:外模分块、加模柄、做分块记号(外面)
4. The outer mould is divided into sections; handles and identifying signs are added (side view)

图五:壘心模(钟侧剖面)
5. The core is built up (cross section)

图六:卸外模囗囗心模木棍钉(剖面)
6. The outer mould is removed; the wooden spikes are driven into the core (cross section)

图七:刮完心模(剖面)
7. The core is scraped down (cross section)

图八:浇注铜液前(钟侧剖面)
8. Before pouring molten bronze into the mould (cross section)

Piece-moulding was still in use in China in the 1950’s, and was documented by Wen Tingkuan in an interesting article (1958). Here on the right are the illustrations from that article, showing the stages in producing a mould for a large bronze bell.

For more on the monumental iron castings of China see Wagner 2000 (translation, Wagner 2007). Of the vast body of research on piece-mould casting of bronze in ancient China, see especially Tan Derui 1999. Liu Yu (2009) gives a thorough review of the literature.

Chaplets

Taken from THORS eLearning Solutions. This version has English subtitles.  

In piece-moulds as well as some other types of mould it is often necessary to stabilize the core using a piece of metal which foundrymen call a chaplet (Chinese xincheng 芯撑). The little film on the right shows the basic idea. The chaplet is made of the same metal as the casting. It holds the core in place as the molten metal is poured and becomes a part of the finished casting.

Taken from Mechtech’s web-site.

In modern industrial practice the chaplet is usually a small rivet-like object, as can be seen in the film or in this diagram. In earlier times the chaplet was simply a piece of metal with the same thickness as the desired casting.


The photographs below show traces of chaplets used in the casting of four ancient Chinese bronze vessels in the collection of the Freer Gallery of Art (FGA) in Washington, D.C., U.S.A. (Pope et al. 1967–69, 1. 47, 191, 359, 603; 2: 101, 103, 151, 104). It seems that some of these chaplets were broken pieces of earlier vessels.

Hu 壶, Shang, FGA 48.1. Fangding 方鼎, early Zhou, FGA 50.7. Gui 簋, early Zhou, FGA 11.38. Lian 囗, Han, FGA 51.2.
Chaplet with leiwen 雷文 imprint, one of two symmetrically placed under the bulge of the hu. Apparently a broken piece of an earlier vessel. Chaplet, one of four at the centers of the sides of the fangding. Chaplet on the bottom of the gui, disturbing cast-in lines. Chaplets with a slightly different alloy composition have a lighter patina from the rest of the lian.

Wu Kunyi et al. (1984) have noted the use of chaplets in the casting of the famous Iron Lion of Cangzhou, but in general it does not appear that Chinese archaeometallurgists have paid much attention to chaplets in cast bronze and iron artefacts. I have observed traces of chaplets on several iron pots in Chinese museums – studies of these would give important new insights into ancient iron-casting techniques.

Sand moulds

Sand-moulding has been used in many parts of the world since early times. It is very commonly used when the production of numerous identical castings is required – in pre-modern China, millions of bronze, brass, and iron coins. The little film on the right shows the basic principles: Sand mixed with a small amount of clay (or some other binding agent) is packed into a box, called the flask, and a pattern is pressed into it. This is done in two parts, called the cope and the drag. The sand is dried at a low heat, the patterns are removed, and the parts are put together, possibly with a core in between. Molten metal is poured into the resulting mould through the feed hole, which was formed as part of the pattern. After the casting is removed from the mould, the sand can be recycled.

The most common binding agent mixed with the sand is clay. Horse or cow dung has been used in some places, but when this is touched by the hot molten iron it gives off toxic gases, so it is not used today. Modern industry uses not only clay but often some more specialized binding agents.

The diagram below shows the usual English terms for the different parts of the mould. Some of these terms are very curious, for they are not related to the usual meanings of the English words: cope (铸模上型), drag (下型), flask (模型箱).

bernierinc.com/different-parts-sand-mold-features/

In completely modern foundries the whole operation of sand-casting is automated (for example 中铸机械), and there is little to see. The films below show sand-casting as it has been practised in early-modern and old-fashioned foundries.

Casting a complex pipe-fitting at an English foundry, 1940’s?
www.youtube.com/watch?v=dqSGTjipFxg
Casting manhole covers in India for New York City, 2014 Casting machine parts at an old-fashioned Danish foundry, 1983 Casting an iron wheel at a foundry in Göttingen, Germany, by Matthias Burger, 2000's?
www.youtube.com/watch?v=eTr8cscmx-M

 

Examining castings for flaws can tell something about the casting process used. In the casting of this manhole-cover in Denmark, we can see that the sand has not set perfectly. The pattern may also have been old and worn.

 

A combination of piece-moulding and sand-moulding – Tajiks in Afghanistan

The Tajiks are the majority ethnic group in Tajikistan and Taxkorgan Tajik Autonomous County 塔什库尔干塔吉克自治县 in China, and a minority people in Afghanistan. This silent film shows the casting of iron ploughshares and vessels at a traditional iron foundry in Afghanistan, operated by two Tajik brothers.

It is a surprise to see that the method is exactly the same as the traditional Chinese piece moulding, but using sand rather than clay for the mould. It is clearly a combination of two traditional Chinese techniques, and was undoubtedly introduced from China. It is very likely that we see here how some iron was cast in China at some time in the past. (When? Song? Ming? I can't even guess.)

A detailed account of what is happening in the film, with illustrations, is here.

0:08:22
The first takes in the film show the preparation of the moulding sand. Clayey quartz sand is fetched from a nearby river in large shallow wooden bowls. This fresh sand is mixed dry with a large amount of used moulding sand and then sieved so that the dust-like parts, which would give the mould poor gas permeability, is blown away. The sand obtained in this way is mixed with water and is then ready to be moulded (see Figure 13).

1:40:17
Then the core (the part of the mould that forms the inner cavity filled by a casting) for a cooking kettle is formed. As in the preparatory work, this is also done by the foundryman and his brother. They use a cast-iron disk, designed and cast by themselves, resembling a potter’s wheel, which runs smoothly on a ball bearing. A thick mould-plate is made on the disc of dried clay mixed with chaff. This is the base for the mould (cf. Figure 14). While the assistant continuously turns the wheel the moulder puts a ring of sand on the base. In order to save moulding sand, he puts old sand in the middle, which he then covers with moulding sand. He roughens up the resulting surface and continues to build up the mould, then presses it firmly to give it its final shape: He scrapes the rotating form with a spatula (a type of knife without a handle, see Fig. 15) and the resulting surface is smoothed by placing the spatula flat and by dripping on blacking (mixture of fine charcoal dust and fine-grained sand with water; production of this will be shown later in the film), which gives the mould a very fine smooth surface. The core produced in this way is placed in the sun to dry (see Figure 16).

6:15:06
This is followed by the production of the mould for a ploughshare, or rather, plough-shoe (see Figure 16). In contrast to the production of the core for the kettle, a model made of wood is used here (see Figure 17a). First, a 15 cm thick layer of moulding sand is placed on the moulding plate. This time it is laid in sand in which the model is halfway embedded. This gives the lower part of the two-part mould. Dry, fine quartz sand is sprinkled on this dividing plane to prevent it from sticking together with the subsequently formed upper part of the mould. The sand protruding at the back of the model is cut off flush with the model surface, so that the model can be pulled out of the closed form. A recess is cut out on both sides of the upper part so that the upper part can later be lifted off easily. This mould is then also placed in the sun to dry.

9:45:17
Then the core is made for a vase; its production corresponds to that of the kettle core.

12:41:06
After a few days, the core of the kettle mould is dry and firm. It is still on the mould-plate. The outer mould is now formed over it on the mould-plate. A layer of moulding sand about 5 cm thick is placed on top and pressed down (see Figure 12).

14:01:00
After a short drying time, this outer mould is cut into three equal parts by three cuts from top to bottom. These cuts are made by feel alone: it is cut in until the resistance of the dry, solid core is felt.

14:46:16
Small triangular cuts are made at the bottom. These form handles when the shell thirds are later lifted off. Their positions in relation to one another are marked by simple patterns, and the funnel-shaped sprue hole is cut out at the tip. The mould is then taken away to dry again (see Figure 18).

15:17:21
The moulder then creates the outer form for the vase in a similar way.

17:06:15
Now the production of blacking is shown. In a shallow bowl, charcoal dust, fine quartz sand, and water are mixed to make a thin paste. This is filtered through a fine sieve into a second bowl in order to remove any coarse components. (This making of the blacking should have been shown earlier in the film.)

17:51:12
In the film this is followed by the final work on the mould for the kettle, which is still on the mould-plate. The three outer mould parts are lifted off and a layer corresponding to the wall-thickness desired for the cast kettle is removed from the core. For this purpose, a spiral furrow is turned from top to bottom in the rotating mould with the tip of the spatula. This gives the constant wall thickness of the cast kettle. Then the sand is removed with the spatula to the bottom of the furrow and the surface is smoothed.

20:04:06
To check whether the wall thickness is the same everywhere an external mould part is put in place. The moulded parts are blown clean with a bellows, rubbed with a piece of fur, and dripped with blacking. Circumferential grooves are now carved into the smooth surface of the core with the tip of the spatula; these serve later as measurement marks in cooking.

23:46:10
Then the core for the two-part outer mould of the ploughshare is made in one piece with the lateral end-piece of the outer form (see Figure 17b). The mould is filled with moulding sand through the side.

24:50:10
When the core is dry it is removed from the mould. The core is scraped off with the spatula by the amount of the wall thickness of the ploughshare (see Figure 19) and then smoothed with blacking. Before the inner surfaces of the outer mould are also smoothed with the spatula and blacking, the mould for the ploughshare is moulded into the upper and lower part with the spatula. Now the two outer mould halves are put together. At the side of the outer mould, a piece is cut out at the top to form a pouring hole. The mould is then ready to be poured (see Figure 17b).

26:46:23
The moulds are ready; now preparations are made for casting. First the wooden tuyères of the bellows are covered with wet clay to protect them from the heat when they are inserted in the cupola furnace. The same is done with the ladle. In this part of the film the bellows is clearly visible; later it hardly comes into the picture clearly: It is a goatskin that is closed at the top with two wooden sticks, and at the bottom has an open leg-stump with a wooden tuyère.

In some of the takes one can also see the cupola furnace from different sides. There are actually two furnaces built at right angles to each other: One of these, the older one, which had slag before it was tapped, had recently burst and therefore was out of operation. (According to the foundryman it could be repaired.) Behind the furnace is a 250 cm high wall made of clay like the furnace. This is a heat shield behind which an assistant works with two bellows side by side. Each of the furnaces is roughly cubical, about 110 cm on each side, with straight walls and slightly rounded corners. The taphole on the front is about 40 cm above the ground; the walls of the furnace are tapered towards the top; an opening about 40 cm in diameter remains at the mouth (see Figure 20).

27:25:09
[The pig iron and scrap iron to be charged into the furnace.]

27:50:02
A number of other takes show the charging of the cupola furnace. First, embers and charcoal (brought from the founders’ home) are kindled to a fire with the blower, which is inserted into the furnace through the taphole below. This hole is now closed with clay, a pottery shard is pressed in, and a stick is placed against this as a support.

29:20:04
Now comes the actual charging: Charcoal and raw material are alternately charged in from above, while an assistant has begun working the bellows. The raw material consists of cast iron and pig iron in roughly equal proportions, as obtained from Ariana. With the help of a simple beam balance, cast iron and crushed limestone are measured out in a ratio of 2:1 and put into the furnace, the limestone probably as a flux. The filled furnace must burn for a few hours before it can be tapped – in our case it was about 5 hours.

31:00:07
While the iron melts in the furnace and collects at the bottom, a circular trench is dug in the hearth (lined at the bottom with loam topped up with moulding sand) in which the moulds are placed and covered with sand up to the pouring opening (cf. Figure 21).

32:06:18
Then the taphole is broken open with an iron rod and the liquid iron is collected in the ladle. When the pan is full, the assistant closes the taphole by hand with a lump of clay. The liquid iron is quickly poured into the moulds embedded in the hearth, the overflowing iron being broken off at the sprue with a spade while it is still soft.

34:24:22
After the castings have solidified and cooled, casting burrs and moulding sand are removed with light hammer blows.

35:27:15
[Casting continues.]

The film does not show that the furnace was refilled several times after the first tapping, and that the casting process was repeated until the iron ran out (and almost all the dry moulds were used), which only happened towards evening. The casting day had started in the morning, the first tapping was done at noon, and work ended in the evening – a very hard day for everyone involved, but above all for the helper with the bellows.

The making of the film

The film was made between 8 and 10 August 1963 in Qurxu, a sub-municipality of Pegug in Zardéu. On 8 and 9 August the forming of the moulds was started. This took about a week for the pieces that were cast on 10 August (the moulds created in front of the camera were of course not yet dry, so they could not be cast in front of the camera). The pace of work of the founders during the period from spring to autumn is roughly that of moulding for about a week and then pouring for a day. Unfortunately, it was not asked whether this must always be the same day of the week.

The foundry is run by two brothers who took over the craft and workshop from their father. The charcoal used came from a neighboring village (a film of charcoal making is also available). The pig iron came from the Ariana mine near Faizabad (otherwise this foundry usually uses iron from a mine near Gurm). The recordings show the process completely, but without repetitions.

F. Kussmaul & F. Schäfer, Tadzhik moulding and casting of iron in Badakshan, Afghanistan, 1963.
See Kussmaul & Schäfer 1973.

Lost wax

Lost wax moulding in China

There has been much controversy over the history of lost-wax moulding in China. In the ancient West, most castings of any complexity were made by the lost-wax method, and studies of Chinese bronzes by art historians in the early 20th century concluded that all of the early bronzes were made by this technique. The reasoning behind this belief was that the castings were too complex to be made by any other means. After investigations by a practical man, the Swedish founder Orvar Karlbeck (1935), it became clear that there was no evidence for lost-wax casting of any of the then-known ancient Chinese bronzes; all were made by the piece-moulding technique. For many years thereafter it was almost universally accepted that lost-wax casting was unknown in ancient China. The artefacts on which this view was based were virtually all from northern China. As archaeology in southern China matured in the 1970’s, however, a number of bronzes came to light which appeared to be too complex for piece-moulding, and investigations by archaeometallurgists concluded that these were cast by the lost-wax technique (e.g. Hua Jueming & Jia Yunfu 1983). There was then much discussion of the origins of the technique in southern China and the possibility that it had come from the West (e.g. Hua Jueming 1985; Barnard 1996).

Zhou Weirong et al. (2009: 73–78) report on a re-investigation of these southern bronzes and concludes that none was cast using the lost-wax technique. They are composed of many separately-cast pieces, soldered together. Their article includes photographs of details of the bronzes showing casting seams, casting gates, and soldering traces. The authors conclude that lost-wax casting ‘was probably introduced into China to cast statuettes of the Western-style Buddha in the period between the Northern Dynasties and the Sui and Tang dynasties’, 4th–9th century CE.

But quite a stir was raised by Davey’s article (2009: 151–152), for he claimed that the technique in China goes all the way back to the famous Sanxingdui 三星堆 bronzes, usually dated as early as 1300 BCE. He argues that the one he investigated, in the National Museum, Beijing, was in fact cast by the lost-wax technique. His article includes photographs of details which show, among other things, lines in the bronze which appear to represent ‘false cuts’ in the wax model. Davey concludes that the technique came to Sichuan from the West via India and the ‘south-western silk road’. Colleagues in Chengdu have informed me, however, that the object in Beijing is in fact a copy of an original in the Sanxingdui Museum, made, of course, by the lost wax technique.

In lost-wax moulding a model of the desired casting is made of wax, a ceramic mould is formed around it, the mould is heated, and the wax melts and flows out. Molten metal is poured into the space left by the wax. This is the basic principle, but there are many complications and refinements in the process as it has been and is practised.

Lost-wax moulding is much used for art castings, and in modern industry when castings must be made to exacting specifications. However, to my knowledge, it has never been used for iron castings, neither in East nor West, in ancient or modern times. It is therefore not necessary to say very much about it here. Davey (2009) gives a clear and precise description of the technique and its history. Wen Tingkuan (1958b) describes the traditional Chinese process as it was practised in the 1950’s. There are also numerous descriptions on the Web: one good one is on the web-site of the Italian Art founder Vittorio Tessaro. Another is on Baidu.

Two notes on terminology

Today wax is seldom the substance used for the model, and the term used for this technique in modern industry is investment casting (rongmo zhuzao 熔模铸造).

Some writers, writing in English, insist on calling the technique cire perdue, which is French for ‘lost wax’.

Ceramic moulds

This section is largely taken from Wagner 2008: 150–154.

Chinese metallurgists were from the earliest times sophisticated potters, and most ancient moulds were made of clay: sand-casting was a later development.

The moulds for most early Chinese bronze casting were made by the piece-moulding technique. Piece-moulding was no doubt sometimes used in the casting of iron objects in early times, but there seems at the moment to be no evidence of it before – perhaps – the Tang period. The usefulness of piece-moulding was greatest in the making of complex one-off castings, while for mass production other methods were developed. Probably these methods were pioneered by the founders of bronze coins, who needed to produce millions of identical small castings.

Simple ceramic moulds

Two-section ceramic mould for an iron hoe-blade (?). From the Warring States ironworks site at Yangcheng in Dengfeng County 登封陽城, Henan, reproduced from Anon. (1977b, p. 62, fig. 22, artefact no. caiji 采集: 2).

Section of a ceramic mould for two ring-handled knives. From the Warring States ironworks site at Yangcheng in Dengfeng County 登封陽城, Henan, reproduced from Anon. (1977b, p. 64, fig. 39, artefact no. cai 采: 6).

Two examples of simple moulds for iron implements are shown here on the right.
A more complex example, with a core, is here:

a. Section of a ceramic mould for a mattock-head (artefact no. cai 采: 22). b. Ceramic mould-core for a mattock-head (artefact no. Gao-dong 告東 T1: 38). c. Iron mattock-head (artefact no. cai 采: 32).
Artefacts from the Warring States ironworks site at Yangcheng in Dengfeng County 登封陽城, Henan, reproduced from Anon. (1977b, pp. 63, 59, figs. 25, 15, 26).

Two mould-sections like a are placed together, the core b is inserted into the top, molten iron is poured into the gate formed by the cavity in the core, and a mattock-head like c results.

Pattern-boxes in Western Han coin foundries

Zheng Jiaxiang (1959); Han Shiyuan (1965, esp. p. 247, figs. 9–10); Li Gongdu (1977, p. 37, figs. 4–5); Cai Yonghua (1978, pp. 122–3, 125, 126, figs. 1.3.4, 3.5, 3.7, 4); Tang Shifu (1981); Tang Wenxing (1983, p. 75, fig. 1); E Xiang (1986, p. 67, fig. 1); Qian Jianfu (1986, plates, figs. 55–7); Liu Dongya (1985, figs. 3–4, 8); Anon. (1977c, fig. 2); Cai Quanfa & Ma Juncai (1995, pp. 49–53, nos. 5–20); Yu Benai (1987); Li Shengyun & Yun Xuewen (1987); Zheng Ruifeng (1987); Zhang Xiufu (1987); Zhang Haiyun (1987); Jiang Ruoshi (1997).

Mould parts like the ones shown were probably fabricated in the same way as decorated bricks, by pressing wet clay into ‘pattern-boxes’ (mu he 模盒), then carefully removing, drying, and baking. This is illustrated further below. The assembled mould would then be clamped together in some way, plastered with straw-tempered clay or mud, dried, and cast (Li Jinghua 1985b: 51). It is not clear whether the mould-parts could be used more than once; probably so. Pattern-boxes have not yet been found at Warring States ironworks sites, but pattern-boxes made of wood, stone, bronze, iron, or lead for making bronze-casting moulds are well known from coin-foundries of the Western Han period. Attempts to bring order into this terminological confusion include Tang Wenxing 1983; E Xiang 1986; Qian Zhuo 1993; and Liu Chunsheng 1993. In the Chinese archaeological literature these are generally called mu fan 母范, ‘mother-moulds’ (sometimes fan mu 范母, ‘mould-mothers’, or simply fan 范、範, ‘moulds’), but there is not general agreement on this terminology. For example, Cheng Xuehua (1959) calls the moulds mu fan 母范 and the pattern-boxes zu fan 祖范, ‘grandparent moulds’.

Stacked ceramic moulds

Stack-moulding in Foshan, 1987

I visited Foshan Casting Industrial Inc. (广东省佛山市铸造工业公司) in 1987, where they used a stack-moulding process which is very much like the process used at Wenxian in the Han period.

Typical two-part ceramic mould for the stack

The moulds are dried in an oven.

The moulds are stacked, bound with iron bonds, luted with clay, and fired in a kiln.

The mould-stacks, ready for casting.

After casting, the moulds are broken and the iron products removed.

Typical products.

Another moulding technique that probably originated with the coin-founders is stack moulding, in which large numbers of identical moulds are arranged together, with a common casting gate, so that a very large number of castings can be made in a single pour, saving time, labour, metal, fuel, and refractory material. One example is here, from a remarkable excavation in Wen County 溫縣, Henan:


a b c d
Stack-moulds under excavation in a kiln at the Han iron-foundry site in Wen County 溫縣, Henan, reproduced from Anon. (1978a, plate 9, bottom left). Sketches of a stack-mould for casting iron belt-buckles, reproduced from Anon. (1978a, p. 11, fig. 15). a. Mould prepared for casting, with outer plastering of straw-tempered clay. b. Vertical section through mould. c. The casting. d. Exploded view of casting in mould. Photograph of an individual section of the stack mould, reproduced from Anon. (1978a, plate 6, bottom left).

On the site of a Han foundry, a large kiln was excavated which turned out to be loaded with about 500 mould-stacks, fully fired and ready for casting. The large number found meant that a few could be used for direct experimental casting, and one result is shown at c. Below is a reconstruction of how the individual moulds in the stack were made.

Reconstruction of the process of making the pattern-box for a mould section like that shown above, reproduced from Anon. (1978a, p. 20, fig. 23). 1. Model buckle and a wooden plate with depression to receive it. 2. Box built around the wooden plate. 3. Pressing clay into box. 45. Two ceramic moulds made in this way. 6. Box built around these two ceramic moulds, with model for runner added. 7. Complete mould for casting metal pattern-box. 8. Cast metal pattern-box.

 

Moulding

Modern mould design: Ruddle 1956; Flemings 1974; Webster 1980.

Artisanal mould design: e.g. Palmer (1912); Laing & Rolfe (1960); or any of numerous other older manuals of foundry practice.

Hua Jueming’s calculations: Hua Jue Ming (1983a); Hua Jueming (1983b); Anon. (1978a, pp. 27–34).

The design of moulds is a very complex affair. Today a good deal can be calculated, taking into account such quantitative variables as surface tension, viscosity, flow rates, heat conduction, cooling rates, and shrinkage, but the placement of gates, runners, risers, vents, dross traps, and the rest was until recently a matter for the experience and judgement of the artisan. To a considerable extent it still is. In the case of these stack-moulds Dr. Hua Jueming 华觉明 has applied the modern calculations and shown that the arrangement of runners is close to optimum, assuming only that casting takes place with the mould pre-heated to about 600° C.

Iron moulds

Another approach to the mass production of castings can be seen in the use of cast-iron permanent moulds for casting iron implements. The iron moulds shown here are from a Warring States iron-foundry site in Xinglong County 兴隆县, Hebei, excavated in 1953. They were one of many surprises of the 1950’s for the archaeology of iron in China. Since then iron moulds have been found at numerous ironworks sites of the Warring States, Han, and Six Dynasties periods.

a b c

Three-section cast-iron mould for casting an iron hexagonal hoe-head, from the Warring States iron-foundry site in Xinglong County 兴隆县, Hebei. a. Photograph of the assembled mould. b. Sketch of the parts of the mould. c. Sketch of a hexagonal hoe-head from the same site. Sketches reproduced from Zheng Shaozong (1956, pp. 31, 35, figs. 2, 9); photograph supplied to Joseph Needham by the Chinese Ministry of Culture through Rewi Alley.


a b c

Three-section cast-iron mould for casting an iron axehead, from the Warring States iron-foundry site in Xinglong County 兴隆县, Hebei. a. Photograph of the assembled mould. b. Sketch of the parts of the mould. c. Sketch of an axehead from the same site. Sketches reproduced from Zheng Shaozong (1956, pp. 33, 35, figs. 5, 9); photograph supplied to Joseph Needham by the Chinese Ministry of Culture through Rewi Alley.

John Evans (1881, pp. 438–48) discusses prehistoric European bronze moulds, and lists about 40 examples. Coghlan (1952) describes in detail an ancient Egyptian bronze mould for three arrowheads, possibly from the –8th or –7th century. E. Voce (in Coghlan, 1951, pp. 112–15) describes experimental casting of bronze in an ancient bronze mould.

There was a brief period of doubt about whether these moulds could really be for casting iron, or perhaps must be for bronze, but the question was soon cleared up by working metallurgists. Metal moulds are quite often used in casting metals. Large numbers of bronze moulds for bronze are known from the ancient West, and in China both bronze and iron moulds were commonly used in casting bronze coins.

Sketch of the whole process of casting the parts of an iron mould for a V-shaped ploughshare cap, using artefacts from the ironworks site at Wafangzhuang in Nanyang 南阳瓦房庄, Henan, reproduced from Li Jinghua (1965, foldout fig. 6; also 1991a, p. 34, fig. 29). Shaded areas are the working faces of the ceramic moulds, as indicated either by refractory facing or by casting traces. Nos. 1, 2, 5, 6, 11–14 are based on actual artefacts. Nos. 10 and 13 show the final cast implement.

1–2. Two parts of ceramic mould for upper part of iron mould (no. 7) (resp. artefact nos. T49:2, T49:1; cf. no. 11).
3–4. Two parts of ceramic mould for iron mould-core (no. 8) (plaster reconstructions).
5–6. Two parts of ceramic mould for lower iron mould (no. 9) (resp. artefact nos. T49:3, T49:4; cf. no. 14).
7. Upper part of iron mould (plaster reconstruction).
8. Iron mould-core, outer and inner sides (plaster reconstruction, cf. no. 12).
9. Lower part of iron mould (plaster reconstruction).
10. V-shaped ploughshare-cap (plaster reconstruction, cf. no. 13).
11. Part of ceramic mould for upper part of iron mould (artefact no. T10:10; cf. no. 1).
12. Iron mould-core (artefact no. T39:9; cf. no. 8).
13. V-shaped ploughshare-cap (surface find, no. 4:1; cf. no. 10).
14. Part of ceramic mould for lower iron mould (artefact no. T49:5; cf. no. 6).


Arrangement of the iron mould for pouring (nos. 7–9 in the figure above), reproduced from Li Jinghua (1994a, p. 116, fig. 58).

Stone moulds

Stone moulds for casting bronze have been found at many Shang and Zhou sites around the periphery of the Chinese culture area. Curiously, none have been found in the Central Plain itself (Wagner 1993: 20).

Some writers contend that it is impossible to cast bronze in a stone mould (e.g. Smith & Watson 1979: 105, 218; Higham 1989: 149), and this has led to much speculation about what these artifacts were used for; but R. F. Tylecote (1973) has shown experimentally that the contention is quite incorrect. The moulds are not difficult to carve with bronze tools, and after certain problems have been solved by trial and error, ‘casting [bronze] in stone moulds is a positive delight compared with sand casting’.

Stone mould for a ploughshare, Zhujie Commune, Qujing County 曲靖珠街, Yunnan (Wang Dadao 1983: 1022, figure 4).

Wang Dadao (1983) describes traditional methods of casting both bronze and iron in stone moulds which are still used in parts of Yunnan today.


And here is a video of the casting of ploughshares in stone moulds in the same way in Huize 会泽, Yunnan, extracted from a longer video kindly provided by Yang Ruidong 杨瑞栋:

References

Andersen, Poul. 2001. The demon chained under Turtle Mountain: The history and mythology of the Chinese river spirit Wuzhiqi. Berlin: G+H Verlag. 

Anon. 1977b. ‘Henan Dengfeng Yangcheng yizhi de diaocha yu zhutie yizhi de shijue’ 河南登封阳城遗址的调查与铸铁遗址的试掘 (nvestigation of the Yangcheng site in Dengfeng County, Henan, and trial excavation of an iron-foundry site). Wenwu 文物 1977.12: 52–65. By the Archaeological Excavation Group, Museum of Chinese History 中国历史博物馆考古调查组; Dengfeng Work Station, Henan Provincial Museum 河南省博物馆登封工作站; and Dengfeng County Institute of Cultural Relics Preservation 河南省登封县文物保管所).

———. 1977c. ‘Sichuan Xichang faxian huoquan qian fan he tong ding ’ 四川西昌发现货泉钱范和铜锭 (Moulds for huoquan copper coins and copper ingots discovered in Xichang County, Sichuan). Kaogu 考古 1977.4: 284–285. 

———. 1978a. Han dai die zhu: Wenxian hong fan yao de fajue he yanjiu 汉代叠铸 温县烘范窑的发掘和研究 (Stack casting in the Han period: Excavation and study of a mould kiln in Wen County, Henan). Beijing: Wenwu Chubanshe 文物出版社. By Henan Provincial Museum 河南省博物馆 and the Editorial Committee for The History of Metallurgy in China 《中国冶金史》编写组.

Barnard, Noel. 1996. ‘The entry of cire-perdue investment casting, and certain other metallurgical techniques (mainly metalworking) into south China and their progress northwards’. In Ancient Chinese and Southeast Asian bronze age cultures, edited by F. D. Bulbeck Taipei, pp. 1–94.

Cai Quanfa 蔡全法, and Ma Juncai 马俊才. 1995. ‘Xinzheng Zheng Han gu cheng chutu de zhanguo qian fan, youguan yiji ji fanying de zhuqian gongyi ’ 新郑郑韩故城出土的战国钱范、有关遗迹及反映的铸钱工 (Coin-casting moulds of the Warring States period unearthed at the Zheng–Han city-site in Xinzheng, Henan, the related sites, and the technique of coin casting). Zhongguo qianbi 中国钱币 1985.2: 48–54 + 74. 

Cai Yonghua 蔡永华. 1978. ‘Jiefang hou Xi’an fujin faxian de Xi Han, Xin Mang qianfan’ 解放后西安附近发现的西汉、新莽钱范 (Coin-moulds of the Western Han and Wang Mang periods discovered in the vicinity of Xi’an, Shaanxi, since Liberation). Kaogu 考古 1978.2: 122–129. 

Cheng Xuehua 程学华. 1959. ‘Xi’an bei jiao Xin Mang qian fan yao zhi qingli jianbao’ 西安北郊新莽钱范窑址清理简报 (A coin-mould kiln of the Wang Mang period in the northern suburb of Xi’an, Shaanxi). Wenwu 文物 1959.11: 12–13 + plate. 

Coghlan, H. H. 1952. ‘Casting moulds made in metal’. Man 52: 162–4 (article no. 245). 

Coghlan, H. H. (et al.). 1951. Notes on the prehistoric metallurgy of copper and bronze in the old world. Including an examination of specimens from the Pitt Rivers Museum and bronze castings in ancient moulds by E. Voce.  (Pitt Rivers Museum, Occasional paper on technology 4). Oxford: Oxford University Press. 

Davey, Christopher J. 2009. ‘The early history of lost-wax casting’. In Metallurgy and civilisation: Eurasia and Beyond. Proceedings of the 6th International Conference on the Beginnings of the Use of Metals and Alloys (BUMA VI), edited by J. Mei and T. Rehren. London: Archetype Publications.

E Xiang 阿祥. 1986. ‘Qian fan mingci jianshi’ 钱范名词浅释 (Glossary of terms related to coin-moulds). Zhongguo qianbi 中国钱币 1986.2: 66–67 + 38. 

Evans, John. 1881. The ancient bronze implements, weapons, and ornaments of Great Britain and Ireland. London: Longmans, Green, & Co. openlibrary.org/books/OL7200998M

Flemings, Merton C. 1974. ‘The solidification of castings’. Scientific American 231.6: 88–95. December.

Han Shiyuan 韩士元. 1965. ‘Xin Mang shidai de zhu bi gongyi tantao’ 新莽时代的铸币工艺探讨 (The technique of coin-casting in the Wang Mang period). Kaogu 考古 1965.5: 243–251. 

Higham, Charles. 1989. The archaeology of mainland Southeast Asia (Cambridge world archaeology). Cambridge University Press.

Hua Jue Ming. 1983a. ‘Stack moulding techniques in ancient China’. Foundry trade journal international 1983.5 (no. 20): 242–246. 

Hua Jueming. 1983b. ‘The mass production of iron castings in ancient China’. Scientific American 248.1: 106–114. 

Hua Jueming 华觉明. 1985. ‘Shilafa de qiyuan he fazhan’ 失蜡法的起源和发展 (The origin and development of lost-wax casting). Keji shi wenji 科技史文集 (Papers on the history of science and technology) 13: 63–81.

Hua Jueming 华觉明, and Jia Yunfu 贾云福. 1983. ‘Zeng Hou Yu zun, pan he shilafa de qiyuan’ 曾侯囗尊、盘和失蜡法的起源. Ziran kexue shi yanjiu 自然科学史研究 (Studies in the history of natural sciences) 2.4: 352–359.

Jiang Ruoshi 蒋若是. 1997. Qin Han qianbi yanjiu 秦汉钱币研究 (Studies on Qin and Han coins)).  (Zhongguo qianbi congshu, A:1 中古钱币丛书甲种本之一 Beijing: Zhonghua Shuju 中华书局. 

Karlbeck, Orvar. 1935. ‘Anyang Moulds’. Museum of Far Eastern Antiquities (Stockholm), Bulletin 7: 39–60.

Laing, J., and R. T. Rolfe. 1960. A manual of foundry practice for cast iron. 3rd edn. London: Chapman. Orig. 1934. archive.org/details/manualoffoundryp00lain/mode/2up

Li Gongdu 李恭笃. 1977. ‘Liaoning Ningcheng xian Heicheng gu cheng Wang Mang qian fan zuofang yizhi de faxian’ 辽宁宁城县黑城古城王莽钱范作坊遗址的发现 (A coin-mould workshop of the Wang Mang period at the site of ancient Heicheng in Liaocheng County, Liaoning). Wenwu 文物 1977.12: 34–43. By Zhaowuda League Cultural Relics Work Station 昭乌达盟文物工作站 and Ningcheng Xian Cultural Office 宁城县文化馆; written by —.

Li Jinghua 李京华. 1965. ‘Cong Nanyang Wancheng yizhi chutu Han-dai lihua mu he zhufan kan lihua de zhuzao gongyi guocheng’ 从南阳宛城遗址出土汉代犁铧模和铸范看犁铧的铸造工艺过程 (The process of casting ploughshare-caps in the light of Han-period models and moulds unearthed at the Wan city-site in Nanyang, Henan). Wenwu 文物 1965.7: 1–11 + fold-out diagram. 

———. 1991a. ‘Nanyang Beiguan Wafangzhuang Han-dai yetie yizhi fajue baogao’ 南阳北关瓦房庄汉代冶铁遗址发掘报告 (Excavation of a Han-period iron-smelting site at Wafangzhuang, Beiguan, in Nanyang, Henan). Huaxia kaogu 华夏考古 1991.1: 1–110. By Henan Provincial Cultural Relics Institute 河南省文物研究所; written by —.

———. 1994a. Zhongyuan gudai yejin jishu yanjiu 中原古代冶金技术研究 (Studies of metallurgical techniques in the ancient Central Plains). Zhengzhou: Zhongzhou Guji Chubanshe 中州古籍出版社. 

Li Shengyun 李盛蕴, and Yun Xuewen 云学文. 1987. ‘Jieshao jizhong Wang Mang qian fan’ 介绍几种王莽钱范 (Some coin moulds of the Wang Mang period)). Zhongguo qianbi 中国钱币 1987.4: 46–8 + plate. 

Liu Chunsheng 刘春声. 1993. ‘Xin Mang qidao, cuodao, daquan zufan shulüe’ 新莽契刀、错刀、大泉祖范述略 (A ‘grandparent mould’ for three types of coin of the Wang Mang period). Zhongguo qianbi 中国钱币 1993.2: 52–54. 

Liu Dongya 刘东亚. 1985. ‘Henan zhengji de “wuzhu” ji “daquan wushi” qian tong fan’ 河南征集的“五铢”及“大泉五十”钱铜范 (Bronze moulds for wuzhu and daquan wushi coins collected in Henan). Wenwu 文物 1985.6: 95–96. 

Liu Yu 刘煜. 2009. ‘Yinxu qingtong liqi zhuzao gongyi yanjiu zonglun’ 殷墟青铜礼器铸造工艺研究综论 (‘A comprehensive survey of studies into the casting technology of the bronze ritual vessels from the Yin ruins’). Huaxia kaogu 华夏考古 (Huaxia archaeology) 2009.1: 102–113. 

Palmer, R. H. 1912. Foundry practice: A text book for molders, students and apprentices. New York / London: Wiley / Chapman & Hall. openlibrary.org/works/OL7720640W/Foundry_practice.

Pope, John Alexander, Rutherford John Gettens, James Cahill, and Noel Barnard. 1967. The Freer Chinese bronzes. 2 vols. (Smithsonian Institution, Freer Gallery of Art, Oriental studies 7). Washington, D.C.: Smithsonian.

Qian Jianfu 钱剑夫. 1986. Qin Han huobi shigao 秦汉史稿 (History of coinage in the Qin and Han periods). Hubei Renmin Chubanshe 湖北人民出版社. 

Qian Zhuo 钱桌. 1993. ‘Shitan diaomu, muqian de jianbie’ 试谈雕母、母钱的鉴别 (Distinguishing different types of coin-mould). Zhongguo qianbi 中国钱币 1993.1: 76–78. 

Ruddle, R. W. 1956. The running and gating of sand castings: A review of the literature.  (Institute of Metals, Monograph and report series, 19 London: Institute of Metals. 

Smith, R. B. & Watson, W. (eds.) 1979 Early South East Asia: Essays in archaeology, history and historical geography. New York & Kuala Lumpur: Oxford University Press.

Tan Derui 谭德睿. 1999. ‘Zhongguo qingtong shidai taofan zhuzaojishu yanjiu’ 中国青铜时代陶范铸造技术研究 (‘A study of the techniques of bronze casting with clay molds in Bronze Age China’). Kaogu xuebao 考古学报 1999.2: 211–250. 

Tang Shifu 唐石父. 1981. ‘Dui “mu fan” yi ci de shangque ji qita’ 对‘母范’一辞的商榷及其他 (On the term mu fan [‘mother mould’]). Kaogu yu wenwu 考古与文物 1981.3: 128.

Tang Wenxing 汤文兴. 1976. ‘Henan sheng Wenxian Han-dai hong fan yao fajue jianbao’ 河南省温县汉代烘范窑发掘简报 (Excavation of a Han-period mould-firing kiln in Wen County, Henan). Wenwu 文物 1976.9: 66–75 + plate 8. By Henan Provincial Museum 河南省博物馆; Xinxiang District Museum 新乡地区博物馆; and Wen County Cultural Office 温县文化馆; written by —.

———. 1983. ‘Woguo gudai jizhong huobi de zhuzao jishu’ 汤文兴. ‘ 我国古代几种货币的铸造技术 (Some coin-casting techniques of ancient China). Wenwu 文物 1983.2: 74–78. 

Tylecote, R. F. 1973. ‘Casting copper and bronze into stone moulds’, Bulletin of the Historical Metallurgy Group 7.1: 1–5.

Wagner, Donald B. 1993. Iron and steel in ancient China. (Handbuch der Orientalistik, vierte Abteilung: China, no. 9). Leiden: Brill.

———. 2000. ‘Chinese monumental iron castings’. Journal of East Asian archaeology 2.3/4: 199-224. 

———. 2007. ‘Zhongguo gudai de daxing zhutie qi 中国古代的大型铸铁器’. Wenwu keji yanjiu 文物科技研究 (“Scientific and technical research on cultural heritage”) 5: 68–82 + colour plates 10–15. Translation of Wagner 2000 by Li Yuan 李园. donwagner.dk/Daxingzhutie-150dpi.pdf

———. 2008. Science and civilisation in China. Vol. 5, Part 11: Ferrous metallurgy. Cambridge: Cambridge University Press. 

Wang Dadao 王大道. 1983. ‘Qujing Zhujie shifan zhuzao de diaocha ji Yunnan tongqi zhuzao de jige wenti曲靖珠街石范铸造的调查及云南青铜器铸造的几个问题’ (An investigation of casting in stone moulds as practised at Zhujie Commune in Qujing County, Yunnan, and some problems concerning early bronze-casting in Yunnan), Kaogu 考古 1983.11: 1019–1024.

Webster, P. D. 1980. Fundamentals of foundry technology. Redhill, Surrey: Portcullis Press. 

Wen Tingkuan 温廷宽. 1958a. ‘Jizhong youguan jinshu gongyi de chuantong jishu, bing: bansha fa’ 几种有关金属工艺的传统技术,丙:搬砂法 (Some traditional metallurgical techniqus, 3: piece-moulding). Wenwu 文物 (Cultural relics) 1958.5: 41–45.

Wen Tingkuan 温廷宽. 1958b. ‘Jizhong youguan jinshu gongyi de chuantong jishu, yi: Bala zhutong fa’ 几种有关金属工艺的传统技术,乙: 拔蜡铸铜法 (Some traditional metallurgical techniqus, 2: Lost wax.). Wenwu 文物 (Cultural relics) 1958.4: 49–52.

Wu Kunyi 吳坤儀, Li Jinghua 李京华, and Wang Minzhi 王敏之. 1984. ‘Cangzhou tie shizi de zhuzao gongyi’ 滄州鐵獅子的鑄造工藝 (The casting technique of the Iron Lion of Cangzhou). Wenwu 文物 (Cultural relics) 1984.6: 81–85.

Yu Benai 余本爱. 1987. ‘Qianshan xian chutu wuzhu qian tong mufan’ 潜山县出土五铢钱铜母范 (A bronze mother-mould for wuzhu coins unearthed in Qianshan County, Anhui). Zhongguo qianbi 中国钱币 1987.4: 72. 

Zhang Haiyun 张海云. 1987. ‘Shanxi Lintong Youwangcun faxian Qin “ban liang” tong mufan’ 陕西临潼油王村发现秦“半两”铜母范 (A bronze mother-mould of the Qin period discovered at Youwangcun in Lintong, Shanxi). Zhongguo qianbi 中国钱币 1987.4: 19–20 + plate. 

Zhang Xiufu 张秀夫. 1987. ‘Hebei Pingquan de Han ban liang qian mufan’ 河北平泉的汉半两铅母范 (A lead mother-mould for Han ban liang coins from Pingquan County, Hebei). Zhongguo qianbi 中国钱币 1987.4: 38–40 + plate. 

Zheng Jiaxiang 郑家相. 1959. ‘Lidai tongzhi huobi yezhu fa jianshuo’ 历代铜质货币冶铸法简说 (Metallurgical techniques for copper-alloy coins through the ages). Wenwu 文物 1959.4: 68–70. 

Zheng Ruifeng 郑瑞峰. 1987. ‘Kalaqin qi faxian Zhanguo qian mufan’ 喀喇沁旗发现战国铅母范 (A lead mother-mould of the Warring States period discovered in Kharachin Banner, Liaoning). Zhongguo qianbi 中国钱币 1987.4: 37 + colour plate. 

Zheng Shaozong 郑绍宗. 1956. ‘Rehe Xinglong faxian de Zhanguo shengchan gongju zhufan’ 热河兴隆发现的战国生产工具铸范 (Moulds for casting production implements discovered at a Warring States period site in Xinglong County, Rehe). Kaogu tongxun 考古通讯 1956.1: 29–35 + plates 9–10. 

Zhou Weirong, Dong Yawei, Wan Quanwen, and Wang Changsui. 2009. ‘New research on lost-wax casting in ancient China’. In Metallurgy and civilisation: Eurasia and Beyond. Proceedings of the 6th International Conference on the Beginnings of the Use of Metals and Alloys (BUMA VI), edited by J. Mei and T. Rehren. London: Archetype Publications.

Last edited by DBW 27 February 2023