Saturday, 18 October 2014

Pewter

Here's a lovely thing to do over the fire. I did a bit of metal casting when I studied metalwork in my teens and it feels like alchemy every time you cast metal. 

Pewter is a metal that has a low enough melting point to melt over an ordinary fire. Which just adds to the magic.


If you are planning to do this with children then think carefully through the steps you put in place and practise the skill yourself first. 

Hopefully you will get the idea from the following photos. 


You can use anything to make a mold. I quite like using cuttlefish as it is soft and easy to carve even with a nail. It also leaves an amazing patterned imprint on the surface of the metal. 


Remember whatever you cast will come out in reverse, This can be tricky especially with letters. 


A wall of clay around the cuttlefish will ensure the pewter doesn't roll off the sides and can be used to give a nice overall shape to the piece.

You'll need a crucible. Anyone who knows my love of a good contraption will approve Of this spoon lashed into a split green stick with some wire.


Striking the edge of the spoon with a screwdriver gives it a good pouring edge. 


These don't have as big a capacity as casting crucibles but it's easier to get hold of an old spoon. 


The pewter I use is a fine grain lead free* casting pewter. Sold for fishing and craft work it's fairly easy to find online and it goes a surprisingly long way. *The lead free bit is important. Don't be tempted to reuse old pewterware by melting it down.


There comes a point where the grains become liquid. It's important to watch for this stage as the pewter can scorch after it has melted and you end up wasting some. 
Pewter has a low melting point, around 170-230 degrees C (338-446 degrees F) depending on the exact mixture of metals. It seems to work fine on a normal open fire.


 See how the scorched pewter stays in the crucible and the lovely shiny metal comes out from underneath it. 


This is the trickiest bit; getting the metal to stay where you want it and filling the entire mold evenly. You have to move fairly quickly to make sure the metal stays molten. The results of partially filled molds can be quite interesting and if you don't like it then just melt it down and start over. 


Then the exciting part; sitting patiently while it cools. It stays hot for a while but will be ready to turn out after a few minutes. 


The mold can be reused again and again which gets some interesting results. These fish were made by my friend the artist Jo Polack who has a thing about mackerel. You can see the effect of the cuttlefish pattern on the surface. 


Remember to work out your own plan to make sure everyone can enjoy this safely. Let me know if you try pewter casting. I would love to see photos of the things you make. 

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