Clachtoll broch proposed iron piece

Finally I got a weather window to start work on the second piece of my residency.

linteltent1We got a tent erected near to the broch, in the lee of the stones from the rockfall in the broch that the restoration project removed in season one. It was surprisingly easy to heave the stone lintel into the tent on Day 1 and surprisingly uncomfortable working in and out the tent. A lot of climbing in and out bent double and kneeling on uneven rocks was involved over the week. Some days were sunny and some grey and cold, nearly all were windy, with the wind battering the tent onto you as you worked.

tentStoer

So the process was:- firstly brush the bits off, then a layer of oil, which with hindsight was a bad idea; followed by a thin mix of silicon to pick up the details – because of the low temperatures and maybe insufficient mixing of the catalyst this seemed determined to follow gravity onto the groundsheet. However there was no choice but to continue, this time with a silicon layer with thickener. By then it was time to call it an end to Day 2. Although there were plans to return that night it was Day 3 that was spent putting on the third and final silicon layer with thickener. There was now a mighty fine silicon mould, but no way of knowing whether layer 1 had worked out.

siliconlayer

Day 4 was onto the plaster and jute mother mould. I had a long and supportive conversation with the super helpful guy from Special Plasters before starting out. The first layer again seemed determined to make a mould of the ground sheet, but then we discovered that it was going off in the plaster puddles and this mix was perfect for the jute layers. I was paranoid that I’d make a plaster mould that couldn’t be removed, or carried out over the beach cobbles, so I designed a 6 part mould. I made little clay walls for each section and we filled them with three layers of plaster soaked jute with support straps.

lintelplaster1poolWhen I removed the clay wall on each piece I oiled the surface and designed a wedge to ease the separation of the sections. After the third section there was a mishap with the scales and we swapped for a different set. This seemed to hugely improve the consistency of the plaster from there on; and the job speeded up because there was no need to wait for the pools on the groundsheet to go off. The number of sections meant that the work went on into Day 5.

siliconremoveHowever the plaster mould came off in sections as planned. Then the moment of truth, would the silicon mould have laminated, would the first layer have been successful? It was an anti climax, but a very welcome one, when it just lifted off and there it was, the first phase of a long process successfully completed. Perseverance paid off and I came away with a silicon mould that nestles in a plaster mother-mould.

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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.

waxtreeschooli

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.

 

Stone to Bowl grand finale

Last week was my final week of work at Scottish Sculpture Workshop on my VACMA funded Stone to Bowl copper project.

It focused on getting the bellows organised so that I can work anywhere in the landscape. Monday was spent fixing the blower which had arrived fractured. Eden Jolly did most of the work as it involved tig welding, but I did the cleaning of the joins and offered cups of tea. Eden and Fleur (an Erasmus student) made it a super wee base and I went to Portsoy to get it some flexible tubing. fanblowerSept18By Wednesday all was ready to return to copper smelting trials. The smelt balls tend to over heat in the shaft furnace as it’s hard to see what is going on.

smeltfurnaceSept18

So on Thursday I dug a pit furnace and trialed that smelting with great success.I got 35gm copper from 50gm ore in 30 minutes and using about 2kg of charcoal.

smeltballSept185i

On Friday it was time to trial the bowls mentioned in the project title. This was using ore I’d smelted alloyed with 10% silver. The photo shows the open mould after casting. The copper did not complete the pour. I need to redesign the bowls with a thicker base. Even after heating the moulds and with sling casting, the copper would not stay molten in such a thin walled vessel.

slingSept18i

Spending 4 weeks developing processes and tools has been brilliant and the work goes on.

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.

 

Stone to Bowl model making

waxfingersprued I make my models using beeswax from a beekeeper who lives near St Andrews. She and her bees make lovely wax that smells delicious and is just right for making models.

I  started small but wanted to make fine models to challenge the techniques. I made finger tip rings by dipping my fingers in the melted wax. stonetobowlJuliaCowieThese then need to have pouring stalks added (sprues). They are then ready to be dipped in the clay mix to build up the mould.

stonetobowlday11iv

After successfully casting finger tip rings I moved on to small bowls which were made by dipping clay bowls in wax and adding pouring stalks.

 

The allure of copper – Stone to Bowl

copperbowl2018

Alongside the traditional copper casting project I have done a copper/silver cast; using plumber’s copper and silver.

copperpourjuneiicopperpourJunei

and two-part sand moulds. This is partly sustainable, with all materials being recycled; but the heat used is gas.

copperpourJune

copperbowl2018i

One of the pieces sold unfinished at ENOS 2018. The bowl has a metal ‘pebble’ inset, a blue heat patina and is almost clean copper on the exterior because I used a different greensand on the outside.

Some learning – try different sands to give cleaner surfaces but retain textures, cost in the silver, keep experimenting, copper is an attractive metal although challenging to work with.