One of the artisans in my SCA Barony offered to teach a bronze casting class in early November. His offer was to cast either an early or later-period sword pommel, but then also offered that students could cast another reasonably flat object if they wouldn’t use a pommel.
One student asked about a penannular brooch, but I had something different in mind – bead hangers in the style of a 9th century Finnish find.
I originally was introduced to this style by a local artist, Master Arks. He did his version quite a bit different, but he shares the original in his Etsy listing, and I really loved it.
I need bead hangers mostly for my 10th century Icelandic costume, but I can’t help but consider my love for all things Finnish, and my 11th century Finnish costume. While for the Finnish costume I’d hang chains and not beads… it might be nice to have an item that could play double duty!
The original has two horse heads, five holes to suspend beads (or chains) and a single main suspension hole. The hanger could also be used alone as a chatelaine, and the five holes could be used for things like keys, bells, earspoons, etc. The animal figures COULD also be dragons, but there is a huge wealth of jewellery items like this from Finland, Russia, and other areas in the Baltic Sea region from this time period that feature animal figures that experts have identified as horses.
A clay positive
In order to do the sand-casting technique our instructor was planning to teach, I would need a positive object to mold. I decided to make this in oven-bake clay… I’ve used this in the past for a lot of different projects. I sized the photo above to what I thought seemed reasonable, printed it, and cut it out.
I wasn’t able to find a museum or other reference to this specific artefact, so I wasn’t able to find the original dimensions. (Frequently even museum websites don’t include this kind of thing… 😦 ) Instead I considered the size I would like the hanger to be – relative to the size of my turtle brooches, how much detail I wanted in the piece, and the likelihood a larger piece might warp.
I used Premo! Sculpey Accents in #5519 Bronze. This has tiny mica particles which create a reflective effect – but in my opinion doesn’t really look like metal. I used the photo of the original to cut out the basic shape and then add in detail with a number of different tools.
I used toothpicks, a straw, a ballpoint pen, a plastic fork, and a wooden chopstick to shape and indent the clay to create the design.
Although the original piece has five holes at the bottom of the hanger, three of these holes are also broken on the original – illustrating that the material was too thin in this spot. I considered this, along with the bead spreaders I purchased while I was in Finland at the Turku Medieval Market. My spreader is only a three-hole spreader, so I opted to make my bead hanger with only three holes instead of five.
I made two bead hangers using the same techniques as much as possible for a “matched set” – although I could create a mold using just one positive clay model and cast several finished pieces from that single mold – I also considered the possibility of USING the clay models… and for that I’d need a matched set.
I also made a third hanger from clay and used a few different techniques to try out something a little different. On this one I added additional clay to the cheeks of the horses, changed some of the stippling, and changed the round decoration above the suspension holes. The two hangers below show the third hanger on the right with the additional clay on the cheeks. The final result is pretty subtle, but I like the extra dimension it gives.
While I had the clay out and would be heating up the oven, I also decided to make a few other objects. I made some brooches a while ago and they didn’t entirely turn out, so I decided to try another one. I also looked at a Viking Age key and did two very different variations on the key using the same techniques as the hangers above. I wasn’t sure if I’d be able to cast a key as well, but thought it would be great if I could!
Casting in bronze
The class took place at a community hall in Calgary, and was taught by an SCA artisan with the society name Maccabi Caiaphas. Mundanely, Craig. The class showed techniques necessary to cast copper, bronze, silver, and gold using sand casting. We focused specifically on bronze, though for larger items (the sword pommels Craig brought for examples) the students used one ‘recipe’ for the bronze, while finer, smaller items like mine and others with small detail he showed us adding more tin (with some pewter he had) to the crucible would make the metal less viscous, and thus would fill the detail better.
I tried to take photos of each step – though not always of my own projects – since my hands got really dirty with the sand! See Master Ark’s photos from the class on Facebook for more!
The first step was filling the flask (the metal container used to contain the project) with a sand-oil mix. Our instructor buys this pre-made, but he said it would be possible to purchase kid’s sandbox sand from the garden centre and mix it with oil (I think he said motor, castor, or vegetable..not sure). We filled one side with the sand in layers, tapping it down with a wood block and hammer so it was incredibly compact.
Then we scraped the top side with a flat piece of wood, and dusted the sand with a mold release – basically talcum powder. This would help our original item we were going to mold from sticking too much to the sand. It also fills in the tiny air pockets on the surface so that the heated air (once the hot metal was poured in) from expanding and pushing against the object we were casting.
With one side dusted, we pressed our original object into the sand about half-way deep. This was really difficult, because of how compacted the sand was. When it was in place, it was also dusted with mold release.
Then we put the other side of the flask on top (there are notches to line them up) and filled it with sand. We did this again in layers, tapping it down with a wood block and hammer (trapping the item we’d be replicating) and once it was very full and compact, scraped the exterior edge as well.
Next… the scary part – separating the two layers. One side seemed to come off easily, but then the other side still held the original object, and getting it out was frequently a challenge while maintaining the shape. Our teacher originally molded a sword pommel, and took three tries to get it to the point where he was happy with the sand mold. This was actually really reassuring, because it showed us a) that getting it perfect on the first try probably wasn’t something we could expect… and b) how to go back and try again – re-dusting our sand, and packing more sand into our flasks to get a more firm and compact mold.
Once we were happy with how our original objects released from the sand mold, we needed to cut in our channel to fill the mold with molten metal (the sprue) and channels for air to release. In the photo below, Master Ark is cutting in channels with a screwdriver into the sand. We left the original in the sand to support the edges as we cut in our channels.
With smaller, more detailed pieces, our instructor said that more channels might be needed. When my piece went in, the channels filled with bronze as well, but they were very fine and were easily snapped off for the most part.
We also used a drill bit to poke through two holes on both sides of our sand-filled flask in the top corners. These holes connected with a channel around the circumference of the flask we cut into the sand. When the metal was poured in, a lot of steam/smoke poured out of these holes!
Once the channels were cut, the original item was removed. Both sides of the mold were dusted with mold release to coat the channels, and then the two halves of the flask were put back together. We clamped the two halves together (at the same time to avoid any kind of see-sawing), and then had two metal plates that were gently clamped to either side of the sand. This was just in case the molten metal and heated air pushed the mold out – the metal would come back up through the sprew (or through the channels on the side) rather than exploding out the sides unexpectedly.
Then – time to pour! I was feeling REALLY phobic about pouring, so I asked our instructor to pour for me. He shared with us that the trick here is to pour consistently – not to stop and start. This means needing to have enough bronze in the crucible to completely fill the mold. The large sword pommels took a lot more bronze than the small bead hanger I was making however.
Before he poured the metal, he removed the slag from the top of the crucible.
He showed us that the metal goes in glowing red – but very quickly cools and solidifies – when the top of the bronze in the sprue is dark – it’s already cool enough to come out of the mold. The mold release powder and some of the sand will burn – so the sand mold can’t be used again as-is… but the red sand can be re-used… you just need to re-pack the flask and put the original back in again. Even though the bronze is cool enough to come out of the mold – it’s still very hot. We plunged it into a metal can of water to cool it, and reduce scaling.
- Video of our instructor pouring the bronze
- Video showing our instructor putting the cast bronze pommel into the water
It was really awesome to see that on the first try, the pour resulted in something cool! There was still a lot of cleaning up to do – the holes to suspend the hanger and beads didn’t ‘take’, and the other decorative holes were much more filled than I wanted.
So clean up was next… I needed to:
- Saw off the sprue
- Drill holes to suspend the hanger and the beads
- File off the channel shards
- File the rough edges
- Polish the whole thing!
I had hoped to make two bead hangers in the class, however we ran out of time. Hopefully Craig will teach the class again and I can have the chance to make the second hanger. In the meantime I can use the single hanger as a chatelaine!
The photo above of the finished hanger looks VERY white – this is mostly due to lighting, but it is a lot “whiter” than a lot of the very yellow bronze items I have purchased.
If I find some very fine sandpaper or some jeweller’s rouge I can possibly clean up the finished bead hanger even more – but for the time being I’m really happy with the finished result! See more of the videos from this class in my Instagram feed! (The #reenactors of instagram tag is especially good!) You can also follow my Facebook page, Dawn’s Dress Diary where I share blog posts, Instagram photos, and interesting links I find online.