Experimental Archaeology at Western Illinois University

On November 1-3 I was in Macomb, Illinois leading a bronze casting workshop at Western Illinois University. This was the first event of its kind for the University and few people knew what to expect. While there is a certain amount of flintknapping and some pottery done by students, there was no available program for the introduction of the method and theory behind experimental archaeology.

Arrangements had been made by Professor Andrea Alveshere, a colleague of mine from the University of Minnesota. There wasn’t much in the way of funds for the project, so I agreed to come as long as my expenses and materials were covered. It was a program that both she and I very much wanted to introduce to the department.

I had a long train ride from St Paul to central Illinois, but enjoyed seeing the landscape. I arrived fairly late that evening and was taken to cabins on rural property now owned by the university. The land and cabins had been bequeathed to the university and they are a great resource. In addition to dorm-like cabins with bunk beds, bathrooms, and limited kitchen facilities, there is a dining hall with a complete kitchen. We made sure that there were supplies for coffee and breakfast and checked out the site for the furnace to be built.

The grounds around the cabin are level and grassy an there was already a large firepit with picnic benches arranged around it. I met the site manager, and we chose a spot beyond the firepit where we could construct a small pit furnace. Fortunately she was excited about the project and had no problems with holes being dug. She also liked the idea of the furnace being buried when we were done with it and to have it excavated later.

We hit the ground running on Thursday. Andrea picked me up and we went to the university where I met students and staff in the art metals department. They were excited about the project and were helping with the supplies. The idea of primitive casting was fascinating to them and they looked forward to the event. I borrowed some tongs and other equipment from them, with more to be delivered the next day. While we spoke one of the professors who teaches pottery came in. We needed clay, and I had to explain that we wanted his worst stuff, the stuff that’s scraped off tables that’s usually discarded or sent for recycling. He didn’t quite understand why we wanted the useless clay, but we could have as much as we wanted.

After lunch we made a run into town for more supplies. We found bags of sand and proper lumpwood/natural charcoal at the local farm store for a reasonable price. The plan was to cast into cuttlefish bone since two days was not enough time to make moulds for lost wax casting. Unfortunately when the shipment of cuttle bone arrived, it contained packages of aquarium gravel. So we were also scouring local pet stores for cuttlefish. Andrea contacted the company she ordered from and arranged an overnight delivery, but there were no promises that it would arrive in Macomb in time. The nearest FedEx office was in Peoria and it would have to go by post from there to Macomb.

We agreed to meet up at the site at 2:30 to build the furnace. When we arrived, a few students were already on site. I explained to them about clay mixing and the reasons we mix sand and dung with the clay. In the process they got a basic lesson about ceramic petrography, and early clay recipes. By the time we were done they had a working knowledge of clay bodies and the physical experience as well. A hole was dug and then lined it with clay. I explained about tuyeres and used a branch to construct a clay-lined hole to the base of the furnace. When I build a furnace I usually ask the students to decorate it in some way. Usually something is put above the hole where the tuyere comes in. While working, the students decided that the furnace should have a turtle head above the tuyere. A nice choice, since the glowing charcoal would make for an interesting turtle shell! While they worked on that, I made the platform (also known as teapot stands or perforated clay slabs) to place in the furnace. By 6:30 pm we had everything done. I needed to change for my talks at 7 pm at the university.

Note the supports for the teapot stand inside. It was a well made and durable furnace.
Note the supports for the teapot stand inside. It was a well made and durable furnace.

Once I was cleaned up Andrea took me to the lecture hall. It was a great facility with a large wall-sized screen and auditorium seating. It was almost half full, which was good considering that it was a weekday evening and the subject was unfamiliar to most people. Despite that we drew attendance from the anthropology and art departments, in addition to members of the local archaeology society and public not associated with the university.

I gave three short talks in succession with questions and answers after each one. These were all presentations that I’d given at conferences, all of which were about 15 minutes long. I started off with the one I gave in Oslo about the significance of mistakes and how they are preserved in metalwork. The second was about Minimum Tools Required, a portion of my PhD thesis that organised the chaîne opératoire of metalworking. The final talk was about excavating metal, based on the BAJR guide that I’d written. The questions were enthusiastic and despite there being little in the way of prehistoric metal in the region, there was interest in the subject. I did answer a couple questions about Lake Superior copper use among Native Americans. There is some debate as to how some of the copper objects arrived in central Illinois from northern Minnesota. Were objects traded by Native Americans, or was the copper a chance find of raw material that had been redeposited by glacial action? I hadn’t seen the objects, but typology might provide an answer. At the end I spoke a little about what we would be doing the next day.

Afterwards Andrea and I returned to the furnace. Although it was still damp, I wanted to get it dry before casting the next day. We laid a little fire and sat talking late into the night. The presentation had been a great success and it looks as if it generated a lot of interest.

Friday I was scheduled to give a talk on experimental archaeology at noon. This was basically an introductory lecture, about why and how experimental archaeology is done, along with the basic ground rules for doing experimental work. Word had gotten out and the room was filled to capacity. After the talk we headed back to the site and got to work. Because we hurried the process along last night there were cracks in the furnace, but because it was set into the ground the cracks had little effect. The furnace was still warm from the previous night and I used a trusty pig scapula to scrape out the ash and leftover charcoal and then fit the platform in place. The fire was lit and after I had worked the bag bellows for a bit, the students took over. Every group I work with seems to have a different approach as to how to operate the bellows. I know that the way I do it, alternating pumps with one per hand, is difficult to coordinate for people trying it the first time. Some people never quite get it and just pump both the bellows at the same time (affectionately known as the Cambridge Method). Here, the students teamed up and had one person per side, operating the bellows with both hands and surprisingly well-coordinated. They were energetic and worked long sessions without tiring. At times I had to ask someone to give up their place to let another student try. I wanted to make sure that everyone who wanted to (including non-students who had come to see what was going on) had a chance at the bellows. With the frequent changes at the beginning the furnace took a bit longer to melt the metal than normal, but we did get there. About an hour after we started Andrea got the call that the cuttlebone had arrived. Students were already carving moulds from what we had on hand. Now things were in full swing. I was grateful to the jewellery professor who took on showing the students how to prepare and carve the cuttlebone while I supervised the melts.

There were a few failures do to improper mould preparation. It gave me the opportunity to explain how easy it was to lose droplets of metal while casting and pointed out the debris that was getting trampled around the furnace, tell-tale clues that an archaeologist needs to look out for in a site that could be mistaken for a cooking pit. Every experience that day was a teaching moment. Both instructional and non-discursive. Repeatedly students told me that they had never known that there was such a thing as experimental archaeology, and that they were thinking about archaeology in a new way. A couple students who had not yet declared were suddenly thinking about the possibilities of having a major in anthropology.

The students wanted to keep going despite a large pot-luck dinner that had been prepared, so they went to eat in shifts. Andrea had made traditional booya, a popular stew in the upper Midwest. There were also pasta dishes, salads, and a wide array of food. People assured me that I wasn’t too soot covered, although I felt as if I had charcoal smoke in every pore. The head of the Anthropology Department came up and complemented me on my lecture. He was impressed by how I presented the information and noted the enthusiasm of the students. The potluck was also attended by members of the local archaeology society who aren’t formally a part of the university, but attend functions and often work with students on projects.

After dinner we worked a little more, but it was long past the time that we could see well in the dark. We packed up as much as we could find and put it all in the cabin.

Blowing off the bits of charcoal before pouring. Always exciting!
Blowing off the bits of charcoal before pouring. Always exciting!

I had the choice of leaving on Saturday or Sunday. I opted for Sunday because the train left at 7 am and I knew that Friday would be a late night. I told the students that if they were interested, we could continue casting on Saturday. I had no lectures or other plans, so we agreed on a 10 am start.

The next morning we had another good-sized group of students. The previous day there had been close to a couple dozen people at a point and rarely fewer than a dozen visiting throughout the day and evening. Saturday was more relaxed, but still well-attended. Students made moulds and instructed ones who hadn’t been there the day before. The more experienced ones were already taking on tasks like they were old hands at it.

Andrea was amused that this was supposed to be my day off, but instead it was another full day of casting. Some experimentation was done with hammering (using my bronze hammer and anvil) and other finishing work. One student was keen on textile archaeology, so she cast some beautiful spindle whorls. I also made some clay ones with her, using some of the scraps left over from building the furnace. Once dry, she’ll take them to the art department to see if she can get them fired there. I heard that they also do raku pit firing.

Towards evening I needed to call it quits. I had an early start in the morning and needed to get things cleaned up and packed. . The students reluctantly poured the last moulds and we got everything in order. The next day they would cover the turtle furnace with dirt and let it deteriorate. In a year or two it will be just as useful as a teaching tool for excavation.

The entire event was successful and exceeded our expectations. We had brought an entire new perspective on archaeology to the department, and the department heads were impressed. In my talk I had emphasised the value of programs like this not only for hands-on student learning, but also as a unique opportunity for public interaction with the department. Too often universities are segregated from the surrounding community leading to the local residents wondering what goes on there. Experimental archaeology programs, especially those performed out of doors, provide an opportunity for interaction and public participation, and even drawing on experience of people from outside the university. Andrea and I discussed the possibility of doing a longer workshop or even the possibility of an accredited short course. Now that the department has been given an idea of what can be accomplished, they might be more amenable to funding it.

These are ambitious ideas in a time when universities are hurting for money. I was glad to be a part of this mainly because I wanted to help Andrea introduce experimental archaeology to her students and colleagues. There was no budget for such an unknown project, but because we were keen on this, Andrea scraped what funds she could get at short notice and we put it together on a shoestring. I would love to pursue this and give students the full range of what an experimental archaeology course could offer, but that is for the university board to decide.

In the meantime, I would like to thank all the people who support my project on Patreon. They provided the opportunity for this seed to get planted and for students to have a unique experience that will benefit them in their careers as archaeologists. The contributions made through Patreon and PayPal go towards giving more people the opportunity to explore the world of material culture in a way they never realised before. If you’re interested in finding out more about my Patreon project or making a sustaining contribution please click on the link below.

Become a Patron!

The furnace at night
The furnace at night

 

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New article in the EXARC Journal

I wrote a brief article about the Bronze Casting Festival for EXARC, a journal dedicated to experimental archaeology and open air museums. This year the EXARC Journal has become open access, so the articles are available for everyone to read.
The article is a condensed version of the experiments and bronze casting that went on at the festival at the Bronzezeithof in Uelsen last May. Those of you who support me through Patreon for $5 per month will have already read this and much more in far more detail.
https://exarc.net/issue-2017-3/mm/bronze-casting-festival-bronzezeithof-uelsen-germany
If you have an interest in experimental archaeology, or are just curious about how people did things in the past, without the benefit of heavy machinery or computers, definitely check out the EXARC journal. There are years’ worth of articles that not only tell you how the pyramids could have been built to how impressions in tiles can tell us about ancient textiles.

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Bellows Forum

I have a fascination with bellows. We know they had to have existed in the Bronze Age, but unfortunately they are also constructed of ephemeral materials, so none have survived into modern times. The only physical evidence we have consists of fragments of tuyeres. An Egyptian painting from the Tomb of Rekhmire, from 1450 BC shows a man using pot bellows that are operated by hands and feet. There are also Chinese documents depicting the use of box bellows. But bellows, after blowpipes, are likely to be one of the earliest forms of delivering air to the furnace.

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Scene from the Tomb of Rekhmire. The man on the right is operating a set of pot bellows. The valve is opened when he lifts both his foot and pulls on the cord attached to the top of the bellows. The air is pushed out of the bellows when he steps down. These require a lot of coordination.

Until a set of bellows is uncovered preserved in a bog somewhere a lot is left to the imagination. How big or small could they be? How can the valves be altered to be more efficient? How heavy should the leather be? Should sturdiness trump suppleness? How are all the parts held together and made airtight? Bellows are one of the most essential pieces of equipment that we have for casting bronze and yet very little information is available about their use and construction from the community of experimental archaeologists and reenactment groups.

Over the years I’ve seen many different shapes and sizes of bellows and always thought that a forum where bellows design and use could be discussed would be invaluable for people to share ideas and experiences.

I would like to invite others to share photos of the bellows they’ve made on this site. This could be a welcome forum for discussing the pros and cons of different designs, what worked, what didn’t. Of course any news of archaeological bellows or tuyeres discovered would add to the fun.

To start, Martijn van Es sent me some photos of a set of bag bellows he made and photos of a new set he recently completed using the tutorial on this website. Martijn casts bronze at the Bronzezeithof Uelsen and Het Bronsvuur – The Bronze fire and is active on the web and Facebook discussing Bronze Age casting techniques and projects that he’s involved with.

 Other bellows designs

I saw these pot bellows in use at Arbeia Roman Fort several years ago. They incorporate partially hollowed tree stumps and circular leather bags with the valve on top. This is one set of bellows that won’t shift around!

Roman reenactors at Arbeia Roman Fort in South Shields, UK using a portable furnace and pot bellows
Roman reenactors at Arbeia Roman Fort in South Shields, UK using a portable furnace and pot bellows

 

This has to be my favourite bellows idea. Simply made from two cement bags.

I welcome others to send in photos of their bellows, and not just bag bellows. Any bellows that could be considered to fit in with what we know or can surmise from archaeology would be interesting for this forum.

If you are interested in making bellows for yourself but don’t know where to start, check out the tutorials on my site for making bag bellows and for making pump bellows.

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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)

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

 

 

 

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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.

 

 

 

 

 

 

 

 

 

 

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Pots on a shelf

 

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Space for metalworking tools and supplies

 

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Wood and antler working area.

 

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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.

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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.

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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.

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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.

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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.

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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.

 

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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.

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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.

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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.

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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.

 

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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.
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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

EXARC

Il Tre di Spade also have a Facebook page.

 

 

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Making bag bellows

Bag bellows might be the oldest form of bellows used. We don’t know for certain because they are made entirely of organic materials, and so none survive in the archaeological record. They are still used for iron forging in parts of Africa and South Asia. Plus they have the advantage of being portable, lightweight, and easy to make. You can be as “authentic” as you want, using only wood and leather, or you can use more readily scrounged materials like vacuum cleaner hoses and cement bags. There is a remarkable video of Kenyan metalsmiths using bellows made of cement bags here.

Traditionally bag bellows are made of soft leather and the usual description is that a single bellow is made from one goatskin. The bellows below are made with upholstery fabric. At the time I made them, leather was too much for my budget. I do find it ironic that in the Bronze Age leather would have been readily available, but hand-woven fabric would have been exorbitant. So, these are my ostentatious display of wealth bellows. They are sealed with a good coating of linseed oil that made them both waterproof and airtight and have worked well for many years now.

 

My very posh bag bellows
My very posh bag bellows

 

Designing the bellows

How big the bellows you make will depend on what’s comfortable for you. I’ve used very large bellows and ones so small you’d think that they’d never produce enough air to get the job done, but they did remarkably well. What is important is that the size works for you. You’ll be sitting on the ground, or close to the ground (I like a padded log or a short tree stump myself). Sit down on the floor and raise your arm a little over waist high. You’ll be pumping your arms up and down for hours, so it’s good to find a height that is comfortable for you so that you don’t wear your arms out. Measure that height or get a good idea of how high that is. You’ll want to add a few more inches because you will want to have the bellows rest on the ground. If you lift them too high, the sides will collapse and you won’t be able to trap the air in them. You also want to add another few inches at the top to wrap around the handles.

The other supplies you’ll need are rawhide, heavy waxed thread, leather or sail needles (depending on the type of material you’re sewing). The handles are made of two straight branches about 3-4 cm (1-1 ½ inches) in diameter, or four boards 3 by 0.5 cm (1 by ¼ inch) by whatever length you decide upon for the width of your bellows. If you use branches, they’ll have to be split lengthwise so that they have a semi-circular cross section. My bellows are about 38 cm (16 inches) wide by 63 cm (25 inches) high.

Using your own measurements, adapt the pattern below, adding about an inch for the seams around the edges, and extra at the top to wrap around the handles.

bellows pattern better

 

You’ll also want loops for your fingers. The loops are more important than you realise. Getting them right will mean the difference between being able to work for hours, and giving up because you keep getting blisters or losing your grip. If you used branches, you might not need loops for your fingers, but I find that they make the bellows far easier to use. The loops are simple, just strips of the same material that your bellows are made from. They should accommodate four fingers on one side and your thumb on the other. Sew them so your hand will be about 1/3 to ¼ of the way from the back of the bellows. Having the loops toward the back means that you don’t have to open your hands as wide. Since I work with kids a lot, this was a consideration when I designed them. Also, I have small hands. The loops will stretch over time, so I periodically have to stitch them again to tighten them up.

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Another useful detail is to sew a small triangle in the front of the bellows, just below the handles. When the bellows open, the little triangle in front will allow the bellows to open in a “V” shape and allow you to trap more air. Holger Lönze taught me this trick. It makes it much easier to open the bellows and get more air in.

The triangular piece in the front. Note that I have stitched it so that the triangle folds inwards so that when I close the bellows it is trapped inside.
The triangular piece in the front. Note that I have stitched it so that the triangle folds inwards so that when I close the bellows it is trapped inside.

 

Another detail to work on is the part at the bottom that sticks out. This is where the tuyere will fit. The size you make that will depend on the tuyere you make, and also how much air you want to push through to the fire. If it’s too little, you’ll be expending a lot of energy pushing air through a small space. Too large and you’ll be pumping furiously to get the volume of air through the tuyere. Mine is about 10 cm (4 inches) and tapers a little so I can fit different tuyeres to it in case I ever want to change it.

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The other supply you’ll need is rawhide. Leather can work, but it isn’t as durable or tight as rawhide. The best source for rawhide I’ve found is the pet shop. Buy a rawhide chew bone for a dog and soak it in a bucket of water overnight. The rawhide will soften and you can untie the ends and unroll a nice sheet of rawhide. I cut it in a spiral while it is still wet so I have long pieces. While it’s wet, you can manipulate it easily. Once it’s dry it shrinks to a hard, tight fit.

Now to assemble the bellows

Cut out the leather or material and then stitch it with the outsides together so that when you turn it inside out, the raw edges will be on the inside. Don’t sew it all the way to the top. You want that extra selvedge to wrap around the handles. Make sure you fit the triangle in the front below the bottom edge of where the handles will be.

The next step was the hardest for me. It’s a bit of a pain. You need to wrap the upper selvedge of the bellows around the sticks and sew them tightly into place. If you’re using half-round branches, make sure the flat sides are on the inside so they meet and make a tight fit. It’s annoying if they wobble around. Sew these in tight along the bottom of the sticks, and then sew the tops together at the back of the bellows so that when you open them, they form a “V”.

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The handles stitched in place. Note how tightly they are sewn at the bottom of the handles

 

 

Turn the bellows right side out and admire your work.

There now, try them out. Try pumping them a bit and see if you can open and close them easily. When the bellows open, the little triangle in front will allow the bellows to open in a “V” shape and allow you to trap more air. The action is to open them while the top of the bellows is close to the ground, Lift them, close them when they are as high as you want to lift them, close the bellows and push down. If you lose your grip, you might want to tighten the loops.

If you feel any air leaks in the seams you can seal them with linseed oil. If you made your bellows from fabric, the easiest way to coat them is to hang them on a clothes line outside and slather the oil on with a paintbrush. It takes a long time to dry and smells pretty strong. It’s definitely something to be done outdoors. Keep in mind that it might take a day or two for the linseed oil to dry.

Now in order to use the bellows, you’ll need at least a short tuyere. If you’re not fussed, a hose or steel tubing from a vacuum cleaner work fine. If you want a more Bronze Age look, you can make them from clay or wood. I took a short branch about 4 cm  (3 inches) in diameter and drilled a hole in it using a 2 cm flat bit (1 ½ inch spade bit in the US). If you don’t have a bit or don’t want to use power tools, take a branch of the right thickness  and split it in half. Carve out the centre and fit them back together.

Fit one end of your tuyere into the opening at the bottom of your bellows. Now take the wet, sloppy rawhide and wrap it tightly around the part of the bellows covering the tuyere, making sure to tie the ends off tightly. If your tuyere is made of split branches, keep wrapping so that it holds the halves of the branch together. Depending on the weather and humidity, it might take several hours for the rawhide to dry.

Once everything is dry, try them out. They’ll be a bit stiff at first and will need to be broken in. It takes a bit of practice to get the Open-Lift-Close-Push rhythm going, especially if you do it alternately with both hands. Once you get into it, it gets easier. Think of a cat kneading its paws. If it helps, rock slightly from side to side.

Another tip is to get some thin willow twigs, about the size used for making baskets. Make them into hoops that will fit inside the bag of your bellows. It will help keep them open, especially if you have a tendency to lift them too high.

Keep in mind that none of this is set in stone. These tutorials are meant to be basic, and are based on the things I’ve done. Experiment. Try different sizes and shapes. Feel free to add bits or change things. Adapt them to yourself. If you want to share your experience with bag bellow making, make a comment to the post here.

 Modifications: Well, you can never have too many bellows, and every time I make a new set, I add in some improvements, or I at least experiment with new ideas. The latest addition is twig rings to keep the leather from collapsing. One of the hazards is that the leather tubes leading from the bellows to the tuyere can collapse or get twisted. One solution is making a spring out of willow, but that can dry out and break after awhile. Another solution is to make a ring that is inserted into the leather tube at the bottom front of the bellows. I took some slender twigs (willow or hazel is ideal, but in this case I used cottonwood) and twisted them into a circle. Then I wrapped them in sinew (string will do too). They can then be inserted into the opening and either glued or sewn into place.

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Woven twig ring inserted into the opening of the bellows. This will keep the leather from collapsing or twisting and keeping the airflow steady.

 

 

 

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