Iron Age bronze working

We had such fun at the final public event for the Clachtoll Broch project.

furnaceboyd

Uist Corrigan (who is now at Edinburgh College of Art) joined me and some local folk and volunteer archaeologists. (That’s Uist keeping an eye on the furnace)

recording

We had the bellows from SSW and built the furnace using local clay, sand and horse dung.

bellowsglencanisp

glencanispfurnaceaWe had some local charcoal courtesy of Chris (although most of it came from the Chinese wholesalers in Dundee). Heather Fulton took loads of photos, some of which I’m using here.

We started before dusk and did the final copper smelt of the project.

Katbellowsglencanisp

Just about everyone helped with the bellows, it’s not so easy, but it’s sociable, thanks all who joined in.

We cast the two community bronzes which were lost wax cast.

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This is burning out the wax.

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Pouring the bronze and, below checking out the crucible for the next pour.

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One of the bronzes was a bear foot print, designed by Bill.

bearBZBill

I had spent the previous week preparing the waxes, adding runners and risers and then  dipping them in a clay slurry mix to build up layers of mould which was then finished by enclosing in a cob clay with a pouring funnel.

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We kept the furnace going (and the bellow workers) to pour the last bronzes – One closed oil sand 2-part mould, an open sand box with local sand and clay mix; and a closed 2-part mould (although we ran out of bronze in the end)

furnacesandmould

Most people went up to hear Gordon’s talk, but I’d promised Mandy Haggith that we’d try a copper alloy. So we switched to the hand blower to melt the copper, including from the local smelting, and added some tin grain to get a very local bronze alloy.

The open sand mould was Roz’s bird over waves design; and the closed one Stuart’s panda:-

The next morning I said goodbye to the Art Studio for 2018 and headed back to my studio to finish the final bronzes.

studio

My thanks to everyone for making the Clachtoll broch art project such good fun.

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Clachtoll Art Project – Bronze community sculpture

The other piece that I’ve been working on is a community sculpture.

Eighteen children from Lochinver primary have prepared designs and tried their hand at wax carving using local beeswax.

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Most of the children also did sand piece-moulds to cast metals beads which we then made up into nettle-stringed necklaces. Thank-you to the people who supported me with this workshop.

waxtreeschool

I then cleaned up the waxes so that they would cast well; and using the same method as the children (2 part sand moulds), I cast the first sixteen mini sculptures in bronze. I have been cleaning these – cutting of the running system, filing them back, sanding and polishing them.

waxschoollk

The Ullapool High school children who came to the broch helped run a copper smelt. The copper from that smelt was added to the bronze used for these mini sculptures. The high school pupils also cast pewter pieces using clay models that they had designed themselves.

The community sculpture has been growing with local people making mini sculptures.

groupmouldiiAt a public event on Stoer field we smelted some more copper, which will be used in casting these waxes in bronze (thanks, Nigel, Fiona and Boyd)

Many of the dig volunteers and other people involved with the broch have added their designs, so I have a further 24 waxes cleaned and prepared for casting.

publicsmelt

The discussion on where they may be installed continues, but I hope they can be affixed to bedrock in a safe place near the broch.

The final public event at Glen Canisp on 16th November 2018 will be to cast the final waxes for the sculpture (including copper from the public smelt). We also have a special request to demonstrate the alloying of copper with tin to give bronze. I hope to have more details of the event planning soon.

 

Clachtoll Broch – rock and fallen rock

lintelsfallenMy first impressions of the broch were of the majesty of the stonework and the rock bed that it is built on; and of the disorder of stones that had been part of the broch which fire, sea and time had scattered.

berrock

The bedrock falls to the sea and some of the stones from the broch have fallen this way. The archaeologists say that the broch collapsed in on itself , because the slope of the bedrock made the construction unstable. The recent work on the broch has included structural support and repair to the lintels to re-stabilise the building without embellishment. The work also included moving tonnes of fallen rock from within the building. This was all done by hand as there is no vehicular access to the site.

The stone double wall of the broch that once towered above the surrounding landscape has been in ruins since the time of Christ.

brochentrance

This mini re-cap gives some of the reasoning behind my decision to create an iron piece that is cast from one of the lintels at the site. It is still not certain that I will be able to do this this season as the weather seems to have turned autumnal, but that is the plan. I’ll keep you posted.

brokenlinteli

Stone to Bowl

bloweri

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,

day7smeltblower

This is the model we hope to replicate.

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.

stonetobowlburnoutmoulds

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.

stonetobowlallinmoulds

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.

stone2inmouldcasting

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

stone2allincast

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.