Sixth class have each made a fish in wax. We have made clay moulds of these fish and sent them to the foundry to be cast.
Today’s demonstration showed this process and also helps us understand the work the Bronze Age people had to do to make their tools to farm, hunt and cut wood.
Today we set up our furnace, (which we made from clay) in the schoolyard. We brought a lot of examples of each stage of the lost wax technique to explain the process. There were replica axe heads, a sickle, and a spearhead and some closed moulds of axe heads, and parts of moulds having been opened.
We talked about how Bronze Age people would make an axe head.
The children first handled and had a look at bees wax. The axe head is first made in wax. This is then covered in clay.
Having seen what happened the clay last Wednesday the children understood what would happen when we put it into the fire. All classes guessed correctly how we would get the wax out of the clay.
The mould is put upside down in the fire and the wax is melted out. This leaves an axe shape’s space in the clay. The mould is now ready for the pouring of bronze.
We had already made six little moulds of fish for today’s demonstration.
To melt bronze we need a much hotter fire than our pit firing on Wednesday. The temperature needs to come up to 1200 degrees, so we use charcoal instead of wood.
The fire needs lots of air so we used our bag bellows again. We got great help from Niamh and her daughter Juno on the bellows.
When the fire began to get hot we put in the crucible, (this is a container that can withstand very high temperatures made from clay), containing pieces of hard bronze. We built up more charcoal on top and kept the bellows going.
The moulds went on top to heat. This helps the bronze pour easily into them.
The bronze in the crucible was then checked. When it was red hot and liquid it was ready to pour. The moulds were taken out and set in sand.
Pouring Bronze – Video.
The moulds were left to cool. Then the clay was cracked open to reveal the bronze fish.