Stone to Bowl clay dip moulds; incl wax melt out

Returning to Stone to Bowl:- The photo shows wax melt out and mould firing in the chimney furnace

stonetobowlz

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). Earlier posts explain the process for preparing the clay and horse poo for those who are interested.

stonetobowlday3iv

This photo shows the wax fingers after a first dipping.

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. The fine dip uses Holger Lonze’s dip recipe. Each layer has to dry before the next layer is added.

stonetobowlmouldi

When the mould is built up a clay funnel is added.

The moulds are then ready for the wax to be burnt out.

stonetobowlfurnace

Advertisements

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.

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.

cupan

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.

IMG_1370

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.

Stone to Bowl

The first trial casting of the copper I smelted last year at the Scottish Sculpture Workshop was a success. I added a high percentage of silver (15%) and used the top temperature setting on my electric furnace and the copper alloy poured well. The first mould was a small toy person.

The Stone to Bowl project will use lost-beeswax, ceramic dip moulds and sling-casting, but I’m trialing different parts of the process using other technologies.

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

ironpourixA view into the inferno

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

ironpoureThis 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.

ironpourivAdding 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.

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

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

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

ironpourg copyAndrew and Uist pouring iron

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

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

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

Iron cups

beachironii

The iron pour at the Sculpture Workshop went well. (Steve and I ran the furnace under the eagle eye of George Beasley and Eden Jolly) This is the iron piece that I showed the sand mould for in my last post. The found metal, probably copper, from the beach is now included in the iron.

beachironi

This cup has a flat piece of beach copper in it:-

beachironv

And this has some copper nails that featured in a post in January:-

beachironviibeachironiv

The heat of the iron has melted the copper through to the outside of the cup.