Stone to Bowl

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Finally the hand cranked forge blower has arrived. This is hopefully the last piece of the Stone to Bowl project. The forge blower will deliver air to the furnace, powered by hand rather than electricity. I’ll find out next month at SSW if it can be made to work. If the bellows can be hand powered it means that I can work anywhere,

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This is the model we hope to replicate.

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Review in The Scotsman

“Julia Cowie casts metal vessels and spoons palpably redolent of ancient landscapes and people”.

Sue Wilson. The Scotsman 8th August 20181damascusbowlset

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Stone to Bowl clay dip moulds; incl wax melt out and all-in casting

Returning to Stone to Bowl:-

stonetobowlmouldfiringOnce the wax models have been made and sprued they are then dipped in a slurry mix of clay (this time from Kingsbarns) sand (Cellardyke beach) and fibre (horse poo from near Kilrenny). There are two mixes, one is fine and the early coats are done in this and the other is coarser to build up the outer layers. Each layer has to dry before the next layer is added so it takes several days to build up the mould.

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When the mould is built up a clay funnel is added. The moulds are then ready for the wax to be burnt out. The first photo shows the burn out. Below are the moulds that have been burnt out.

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The link below is to an animated film about lost wax casting, which explains the process well.

https://hyperallergic.com/286780/an-animated-guide-to-the-bronze-age-technique-of-lost-wax-casting/

I also tried out a casting method where you burn out the wax and then put the copper alloy in one end of the mould. You then seal up the mould with a lid and clay mixture and return the mould to the furnace. stonetobowlmoulds

This photo shows the moulds and lids ready for burn out.

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This photo shows the all in one moulds ready to return to the furnace for the copper melting stage.

In theory the copper heats to melting point and you upend the mould and the copper pours into the part that you want to cast, In practice because you can’t see the metal it is difficult not to either get incomplete melting or over heating and the metal seeping out through the ceramic shell.

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The photo shows incomplete melting, the copper is fused (bottom right)

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This photo shows a mould where the metal over heated and seeped through the mould walls. There are two moulds, one complete (but rattles so I’ve not broken it) and an open one.

The moulds with incomplete melting can be ‘re-used’ as open moulds.

 

Clachtoll Broch: Scottish Sculpture Workshop

ironpourg copyIt looks like we should be able to bring an iron pour to Assynt as part of creating my final piece and involving local people. It’s still a long way to go, but it looks like iron will come to the Iron Age broch. The access to the broch site is a big consideration, as is the weather – molten metal and rain do not mix so we will need careful plans (and shelter). I would not use the actual broch site or anywhere that would adversely impact the site and will probably do a lot of prep work at the Sculpture Workshop.

I had a really useful meeting at SSW today with George Beasley, iron artist, and Eden Jolly, Senior technician, to scope out what I could do practically during my Clachtoll Broch artist residency. We could, for example, borrow SSW’s cupolette furnace, pictured, to cast iron in Assynt.

georgebeasleyOnce I’ve had a chance to meet and talk some more with the archaeologists who are working on the broch finds, I’ll be back up in Assynt to carry on working on the design, meeting people and seeking out resources

Thanks to Ross of RoRo studios for the photos.

Stone to Bowl. Copper smelting

Finally I am three weeks into my Stone to Bowl residency and I feel that I should share progress.

One element of Stone to Bowl is to develop a replicable way of smelting copper from malachite/copper ore in a traditional way that means that I can work in the landscape anywhere.

First task was to source some Scottish copper ore. The mine in Bridge of Allan is long closed, but I found some copper traces on the waste heap. These photos show the mine entrance and the pieces that I collected.

After initial smelting experiments I have been putting the ore in closed ceramic  balls with added charcoal to give a reducing atmosphere for the smelt. (While I was on my residency another artist was successfully smelting malachite using oxy-acetylene.)

The furnace is charcoal burning; and for these experiments I was using an electric air blower, although I will use bellows when I understand the process more. The dry ceramic balls are made of a local refractory clay mixed with fibre -horse dung, and sand. Inside is copper ore in pea size chunks  with 25% charcoal. The balls are placed on the furnace charcoal once it is burning well and the furnace is run until the ore is to a high enough temperature to smelt, hopefully. The balls are then plunged into water and broken open.

The first smelt was not a complete success. Some copper was formed, but a lot of this was pelletised rather than consolidated and some had to be panned from the ashes of the furnace.

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However I reheated this copper to consolidate it and a reasonable amount of copper was retrieved. Again I used an electric furnace for this process while I am experimenting.

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I am not sure that a chimney furnace is needed, a horseshoe hearth might be as successful as one can see what is going on. The chimney furnace is made of a refractory clay mix similar to that used for the balls.

I tried another smelt later in the residency of which more anon.

100 Days

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Alongside the Stone to Bowl project I’m doing a 100 days project where I try and do something that is new/not work-driven each day. This silver bowl I started at college, but I now have new skills to finish it properly, so I did.

It is made from rings of silver soldered together and to a textured base and then slightly melted to give the organic finish.

Cambo stables exhibition

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Still time to drop into the new visitor heritage centre at Cambo and see some artworks. Some local artists, including Keny Drew, Judith Heald and Linda Jackson, have a horse stall each to display their work. This is mine.

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It’s a lovely display area and there are interesting displays about the history of the estate and the stables.

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Most days you will find the cafe and shop open as well.

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also your eyes may focus better than my photos…

They reopen 4th January 2018.