Casting Bronze in the Italian Bronze Age Way!

This month (October 2015) I had the great adventure of doing some bronze casting with Il Tre de Spade (The Three of Swords) at the Archaeological Park and Open-Air Museum of the Terramare in Montale. The museum is located just south of Modena and recreates Bronze Age houses surrounded by a palisade and a marsh, appearing as it would have in the central and later phases of the Bronze Age there (1600-1250 BC). The museum hosts demonstrations and activities, along with a recreation of the original excavation.

The houses are nicely furnished, with well laid out areas for cooking, sleeping, food storage, and workshops. One house has a workbench for wood and antler working, along with weaving and other crafts. The other has a metalworking workbench with stone anvils, moulds, bellows, and all the needed kit stored neatly on shelves and a work bench. Unlike the recreated roundhouses that are often seen in the UK, you can get a good idea about how the ancient people lived here and where they put their all the things they used in every day life.

(Click on the thumbnails here to see a larger version)

The ubiquitous Bronze Age warp weighted loom. This one has some rather nice textile in the works.




The cooking hearth and oven. The little device on the side is a wonderful little warming oven with charcoal in the bottom and the food on top. I like to think of it as a Bronze Age microwave.











Pots on a shelf


Space for metalworking tools and supplies


Wood and antler working area.


some of the woodworking tools.

I had been invited to join the casting demonstrations by Claude Cavazzuti, who is also part of EXARC. He is one of Il Tre di Spade (along with Pelle and Scacco) , who were some of the first metalworkers at the museum after it opened several years ago. They do regular demonstrations (sometimes with hundreds of visitors per day) and also run workshops that introduce people to Bronze Age casting and metalworking with a focus on the  Middle and Recent Bronze Age (1700-1150 BC) of Northern Italy.

The furnaces there are small clay-lined trenches about 25 cm deep and 50 cm long, something that would be nearly invisible archaeologically and easily interpreted as a cooking hearth (and really, there’s no reason why they couldn’t be both). The furnaces heat up quickly and work efficiently. The charcoal is concentrated around the crucible with more warming beside it so that the fuel is hot before it gets raked around to cover the crucible.

The furnace. Not much to see here, and even less after a few thousand years!

My first new introduction was the bag bellows. They were larger than I have used in the past, and made of heavier leather. They put out an enormous volume of air, but also their size allows the person pumping the bellows to sit on a low stool. One nice innovation is that they put a large stone in the bottom of each bag. That prevents people who are new to bellowing from lifting them too high and causing the bags to collapse.


The real challenge for me was the valve and the way the bellows open at the top. The bag bellows I’d used before have straight sticks in the handles that either open parallel to each other, or are hinged at the back to open like a “V”. These bellows have two sticks on both sides, so that they open into a diamond shape with the wide part opening where your hands hold the bellows. It took a little bit to get used to them and to figure out where best to position my fingers. I never did get it quite tight enough and could feel a bit of air blasting on the back of my arms, but they still  delivered a powerful amount of air. The tuyere was a large clay tube that curved downwards at a 90° angle, and was positioned so that it was directly above the crucible. This mean that the charcoal had to be moved frequently to keep the crucible covered. Without the layer of charcoal above, the air coming from the bellows would cool the metal in the crucible.

The tuyere with the moulds set next to it to warm up. The small bowls are the crucibles. Note that they are used without lids.

The crucibles are a flattened dish-shape, with some that were larger and a bit more of a bowl shape to hold more metal. They have a tab on one side that is used as a handle. The crucibles have a small lip for pouring that causes the metal to pour more quickly and flow out in an arc, rather than almost straight down like the triangular bag-shaped bellows used in Britain. It took a little bit of getting used to the trajectory of the metal in order to get all the metal in the pouring cups.

The tongs they use are beautifully crafted from wood and cord. They are kept in a bucket of water to keep them from burning when holding the heated crucible. The entire organisation of tools and materials is efficient and elegant, and there is nothing that would not have been found archaeologically from this period.

Beautifully constructed wooden tongs

For the first demonstration a sword was cast into a sand mould. The sand they use is local, and perfect for casting. Commercial casting sand consists of fine sand and dry bentonite clay. The sand from the Po River delta is exactly that, sand that has been reduced to almost a powder by erosion, combined with clay and silt that has been washed into the river. The Po River sand leaves a much finer texture on the finished objects than the coarser commercial sand that I have used here. Looking at the quality of the sand, I could imagine how different sands might affect the regional quality of casting, and might even have had value as a commodity.

The mould for the sword was made using the standard cope and drag method, with the pouring cup on the side of the sword, rather than pouring from the top. A large vent was also placed at the tip of the sword. The mould was placed at an angle. As the crowd gathered and settled onto benches under a marquee, Claude explained Bronze Age metalworking techniques and then the sword was cast. Everyone was impressed and even more so when the sword was taken from the mould.

The sand mould is set up. The hole at the top is the pouring cup. There’s a smaller hole at the bottom, at the tip of the sword that acts as a vent.


Casting the sword.

After the demonstration was done we started up a second furnace for the workshop. For this one we used the stone moulds that were on display in the house. The moulds were made of a very fine grained local stone, the same that had been used by the Terramare circa 3500 years ago. The moulds were warmed next to the furnace and then strapped together with leather strips. We took turns bellowing and pouring. The shallow crucibles mean that the pouring has to be done more quickly than with deeper crucibles. They cool quickly, so there is little time for dragging out charcoal and skimming. Once the metal was molten, we gave it a quick stir with a stick, pulled the crucible out with the wet tongs, and poured the bronze into the mould while holding the stick across the top to keep the charcoal back.

Sickles, knives, and daggers were cast. Later we moved on to using sand moulds. I borrowed one of the antler spindle whorls from the woodcarving house to see if I could try casting that as an experiment. It worked sort-of. It will take a bit of work to get finished up, but I think with a couple more tries we could have got it spot-on.

I was wearing my bronze torc bracelet that day and one of the new people wanted to try casting that. We used it as a model for a sand mould and after a couple tries, we got a cast that made a perfect duplicate.

A display of some of the things cast at the Open Air Museum

While we were casting, more tour and school groups came through to watch more casting demonstrations. School kids also had the opportunity to make their own copper bracelets. There was a square of tables set up with small stone anvils and hammerstones. Punches and chisels were available so they could decorate the strips of copper to make bracelets in patterns that would not have looked out of place in a Terramare village.

Often after the casting is done for demonstrations the bronzes are taken home and finished up using drills and angle grinders, but not here. We had a relaxing time using wet sand on the hard, fine-grained anvil stones to grind off the flashing and excess metal. Some smaller stones that had a coarser texture could be held in the hand and used for working the inside curves and corners. I’d brought my small socketed hammer along and we used that to break off some of the metal, too. Between light hammering and patient grinding, the daggers were smoothed rather more quickly than I would have expected.

A nice flat anvil stone for grinding the flashing off of the dagger blade. There’s evidence from the originals that the holes for rivets were punched rather than drilled, or cast in place. Other stones are used for coarser grinding. Note my hammer at the bottom. It came in handy for breaking off some of the flashing. A bit of time travel here since this is a replica of a Late Bronze Age hammer!

It was a great day, and one that was full of new experiences. It was particularly interesting to see how much variation there is in doing the same tasks and getting successful results. The different types of bellows and crucibles make for differences in how tasks are performed. Other small acts show variation between different metalworking groups. Tasks such as turning the crucible over to remove dross and leftover metal after casting was done into the furnace here, where in Ireland we have always done that next to the furnace. These are small things that could be seen archaeologically if excavation is done carefully, but also shows how customs and metalworking traditions develop with regional differences.

Next month I will be moving to Modena and will be in the vicinity of the park. I hope to do more casting there and to learn more about the Early Bronze Age metallurgy of Northern Italy.

dagger 1
Dagger: This was cast in a stone mould and is partially cleaned (it’s the same one as in the photo above). The pouring cup will be cut off and rivet holes punched into the arched end.


knife 3
Knife: This is as cast in commercial casting sand. It will take a bit of polishing, but I am looking forward to finishing and using it.
sword 1
Sword: This was cast in the natural sand. It’s difficult to see, but the texture is much less gritty than the knife. It’s about halfway between the knife and the dagger for smoothness. It just needs to have the sprue and vent removed and a bit of the flashing taken off before punching the holes for the rivets.


A special thanks to Il Tre di Spade, Claude, Pelle, and Scacco and the staff at the  Parco archaologico e Muse all’aperto della Terramare for inviting me to participate in casting. I would also like to acknowledge Markus Binggeli & Markus Binggeli who are masters of bronze casting and replicating ancient metalworking techniques. They are mentors of  Il Tre di Spade, and provide both inspiration and technical expertise for experimental archaeologists.

Useful links

If you’d like to learn more about the Early Bronze Age in the Modena area, the work of Il Tre di Spade, and the Terramare Open Air Museum in Montale you can find links below.

A film about the Terramare and Bronze Age metalworking (in English)

Italian language sites

Parco archaologico e Museo all’aperto

Musei Modenesi

Parco archaologica sul Facebook

English language sites

Archaeological Park and Open-Air Museum of the Terramare in Montale

Visit Modena tourism


Il Tre di Spade also have a Facebook page.



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What is Experimental Archaeology? It Begins With a Question

My first foray into experimental archaeology came when I was working at the Science Museum of Minnesota, where I was cataloguing the metals collections there. It’s not well-known in the rest of the world, but during the Late Archaic Period (3000-500 BC) in the Lake Superior region of North America, Native Americans worked with the copper that was easily found there. The culture was aceramic, meaning that they did not make pottery, and so did not have the means to cast or alloy the copper they found. However, they could hammer it, anneal it, and create finely detailed cut work ornaments, earrings, and hand tools, in addition to spears, knives, and arrowheads. It was while I was examining the spears that I started to wonder how they were made. The spears were triangular in cross section and I noticed that they were perfectly smooth on two sides, but on the third side the metal was folded with an almost flowing appearance. This was accentuated by fine corrosion on the surface. Knowing these weren’t cast, the first question I had was how they could have been hammered into a raised shape. The clues were in the surfaces and I reasoned that rather than being poured into a mould, they were hammered in, and the rougher surface was where the metal was packed in and hammered from the top. In order to test my theory about how this was done, I carved a block of walnut to create a triangular spearhead. Knowing that copper needs to be annealed periodically, I lit a small charcoal fire and had a friend standing by with bellows. It turned out that they weren’t needed because a light breeze was enough to raise the heat of the charcoal fire to anneal the copper. The metal was easily hammered into the mould using a hand-held hammerstone. The metal pushed into the mould smoothly along the sides and the top surface was rough from my pushing the edges of the metal from the top edges of the mould and folding them back onto the surface of the spear.

I was not only fascinated by the process of making a spear, but also how I had deduced it from examining the original spears in the museum and puzzling out the details. The whole thing was eventually written up and published in The Minnesota Archaeologist.  After the first foray into experimental archaeology, I was hooked. From that time forward, I closely examined tools and metal objects, trying to figure out how they were made, what processes were used, and what tools were needed, how those tools were made, receding back ad infinitum.

This is the crux of experimental archaeology that sets it apart from re-enactment or generally doing craftwork: experimental archaeology starts with a question. Experiments can be done in a lab in order to control as many variables as possible. Experiments can also be done in the field, but unlike re-enactment, not every tool and object needs to be a replica of an original. This is especially true when doing experiments in prehistoric crafts, where few of the original tools still exist. When doing experiments, I can use steel tongs and graphite crucibles, as long as they will not affect the parameters of the question being asked. Likewise in some experiments, for instance trying to learn the melting times for different alloys in a charcoal fire, rather than using bellows I will use an electric pump to make sure that each sample was created under as close to the same conditions as possible. Each experiment must be thought out ahead of time and choices made for each step. The important thing is not to be distracted by the possibilities, but to always focus on the question and to create the conditions that will give a meaningful answer, even if it is inconclusive and leads to other experiments. It’s also vitally important to measure, weigh, time, and quantify as much as possible. For example when experimenting with smelting, the ore should be weighed before and after processing. How long it took for the ore to smelt should be timed. The amount of charcoal used should be recorded. The size of bellows and furnace should be noted. The heat of the furnace should also be monitored. Finally the slag, dross, and refined metal should be weighed and recorded in order to find out how much metal was produced from the ore. The slag could be examined to see if there is any metal left, and note if it could be re-smelted. It can be tedious work at times, and a pain to remember to weigh, record, and photograph everything, but the results will be worth the effort, because the information hasn’t been lost. The data from the experiment you did will lead to more experiments, but will also yield useful information for others.

This is just the beginning. This website will feature experiments that I and others have done, and will also include tutorials on how to construct basic equipment. If you are interested in reading more about experimental archaeology, check out the links page where you will be able to find others interested in experimenting with ancient and even not so ancient technology and craft.

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