iron lintel – the story continues

I spent several days fettling and chasing the iron lintel and cutting off bits that weren’t required. Eden (Senior Tech SSW) assisted with this process – giving advice and moving the piece around for me. He also finalised an ingenious scheme for affixing the piece at its final location.

The lintel just fitted into my van and with further ingenious thinking from Eden it was stowed in a manner that I would be able to get it out by myself (or at least with one other)

I took it over to Stoer and we unloaded it. Unfortunately the weather was changing so the noble lintel moving team called off moving it to the broch that day, but they got together later to carry it in. My heart-felt thanks to them.

We now await a decision on the final location so the lintel can be installed at the broch site where it belongs,

iron lintel casting

The day dawned bright and by lunchtime the mould was finally finished; Eden had mended the furnace and the ‘bull ladle’ was also fixed; the fork lift was in place to take the weight of the ladle; Michael had cracked the scrap iron (thanks Michael) and weighed the bags of coke and iron. Eden must have laid the bed of coke in the furnace when I was working on the mould indoors; the air blowers and gas tanks were in place. It was decided by the tech team to go ahead with the pour.

The furnace was lit and the air blower turned on to force the temperature up to melting point; the gas blower was turned on to the ‘bull ladle’ to heat it up ready to receive the molten iron when the furnace was tapped.

The photo above shows Michael adding a charge of coke and scrap iron to the top of the furnace. As the iron scrap heats it becomes molten and drops to the bottom of the furnace. When enough iron for the pour (over 65kg) is molten at the bottom of the furnace the bung is broken so the iron can run into the ‘ladle/crucible’.

The weight of the iron is taken by the fork lift and Michael and George manoeuvred the bull ladle into position and tipped it to pour the molten iron into the mould. There was a delay when the fork lift wouldn’t start and an alternative lifting device was tried before reverting to the fork lift.

 

Towards the end of the pour the bull ladle got caught in some way and the pour was aborted. The mould was showing metal through the air vents, so the general view was that the pour could be complete. The team have reviewed the equipment and made safety alterations since.

The metal needed to cool before I could peek inside, so I left it for the weekend. On Monday I removed the mould pieces to reveal an iron lintel, yeah

 

Thanks to Scottish Sculpture Workshop tech team and George Beasley.

Packing list NEOS 2

I’m trying out this copper/silver alloy bowl on a patinated mokume gane disc. I’ve tried other stands, but the bowl ‘stands’ well on its own, so I’m going for something simple that highlights the blue patina.

There will be some of my charm jewellery going to Art in the Buchat, Glenbuchat as well. I gave it a little polish and its tucked up in its boxes now waiting to charm visitors from Friday, 7th September.

 

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

Returning to Stone to Bowl:-

Once 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.

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.

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.

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

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.

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

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

 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. These then need to have pouring stalks added (sprues). They are then ready to be dipped in the clay mix to build up the mould.

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

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

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

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.

Iron Casting photos from Studio RoRo

I have some great photos of the Iron Pour that Steve and I supervised at SSW, thanks to Ross Fraser Maclean of Studio RoRo

A view into the inferno

This is George Beasley lighting the furnace for his demonstration run.

This is the team discussing roles, the furnace is running on blown air to maintain and build up heat having been lit with the gas torch.

Adding coke to the furnace onto a charge of scrap iron. The iron scrap melts and drops down to the bottom of the furnace. It is then tapped from the bottom into a crucible for pouring.

Heating the crucible ready for it to receive molten iron for pouring into moulds.

Yvonne taking notes for the log so we know how the furnace is running.

Molten iron tapped from the furnace flowing into the crucible for pouring

Andrew and Uist pouring iron

My sand moulds with clay along the joins to minimize the amount of burning to the boxes.

Eden and I checking how the beach-sand moulds held up

Dropping the bottom when the last tap has been used. This coke can be cleaned and reused.

Iron Pour prep

This is a teaser photo of preparations for the iron pour that Steve and I ran at the weekend. It is the inside of a sand mould for an iron beaker vessel. I have put a piece of copper alloy from my beach combing into the mould to see what happens.

I now know what happened, but you will have to wait….

The pour was a great success thanks to George Beasley, Steve, Eden and the rest of the team at SSW. Thanks also to Charles Clark for the mould boxes.

Hot bronze – Scottish Sculpture Workshop 2

I made some small jugs and some bowls to trial as new forms for casting.

I left 5 sand moulds for hot bronze, more experiments…

And this is a 3 bowl set, I can’t wait to get it cleaned and finished.

 

Scottish Sculpture Workshop (1)

I spent a week exploring developments of my casting. I managed to fit in two bronze pours and remake the moulds ready for a third.

This picture shows bronze ready to pour, with some mould boxes in the foreground.

This picture shows small sapphires pinned into the beachsand mix. I am working on making sapphire windows in the cast bronze bowl.