Thursday, 27 September 2012

Water casting.

As part of a jewellery commission, I have produced today my own alloy from which I will produce a large cuff with an engraved botanical motif.


The alloy I have made is a Japanese type called “Shibuichi”. It is made of copper and silver, in this instance 300 grams of copper and 100 grams of silver.


  These materials are heated together in a large crucible inside my furnace. In order to properly hold the crucible, I forged a specific set of long tongs. Making tongs is a pleasure and it is always worth investing the time to produce a decent set rather than rush.


The tongs were carefully formed to grip the whole circumference of the crucible, rather than to apply pressure on any one particular point.

Once the furnace was brought up to temperature the crucible with the casting grains were placed inside and allowed to melt together.


The method employed here is to cast the liquid Shibuichi into recently boiling water, with a cloth suspended in it.  The theory is fascinating as it relies on the understanding that you are not attempting to quench the liquid metal in hot water, but rather super-heated gas. The ingot of metal will float on top of this gas jacket on top of the cloth and thus not burn through despite being many hundreds of degrees in temperature.

Apologies, the video is quite loud (as ususal!) so turn the volume down
The resulting ingot will be forged out make the blank for the cuff.

1 comment:

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