Enamelling Techniques

Raku

Raku is not for everyone but it can add a finishing iridescence to your work. All is not lost if you do not like the effect as you just refire. The technique of Raku firing was first discovered in Japan in the ceramics industry. As the glazes in ceramics are glass it has been easy for enamellists to test it out on thier work. The only real difference comes at the end of the process. In ceramics the clays used to make the vessels for raku are open so they can withstand thermal shock. Thermal shock happens to ceramic objects when the piece is taken out of the sealed chamber and plunged into cold water, the clay withstands the drastic temperature changes. this part of the process is not recommended with enamels as they are fired to metal.

Once your work has gone through the raku process any future firings will undo the lustre achieved, do it last. Here is a guide to the process.

  1. Enamel your work as usual up to last firing.
  2. The lid of your metal container must be a tight fit, so air is excluded from the chamber.
  3. Prepare your container with your combustible material of choice and prepare all you need.
  4. Combustible materials ie: newspaper, thin white paper, sawdust, fine shavings of wood, very dry leaves, sawdust, anything that will catch alight quickly.
  5. Gloves and apron should be worn for protection from heat. Water should be on hand.
  6. Fire your enamel as normal.
  7. Take it out of the kiln and place as it quickly as possible in the container.
  8. Let the heat from the enamel set fire to the combustible material, at this point you could add more to cover it. Sometimes marks are left on the enamel by the materials you use.
  9. Tightly close the lid.
  10. The fire in the container will go out due to a lack of oxygen and it will smoke.
  11. Do not open the lid too quickly as the material inside could re-ignite. Leave it for 5 mins and open carefully.
  12. Your piece could look very blackened, it will wash off. Clean your work gently and do not fire again unless you are not happy with the effect.
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steel pot for rakuing enamels The container is filled with conbustible materials of your choice. Shown here is newspaper shredded into long strips. Different materials will produce different effects, as will different enamels. Wear heavy gloves and a heavy apron at all times and make sure you are near a water source.  
     
closing raku pot The container is ready to receive your work straight from the kiln. The heat from your enamelled piece will set the paper alight and when it has burnt for a second or two the lid can then be shut tight.  
     
raku pot closed The container has now been shut tight and left for 5 mins or longer. Be aware that if the lid is opened too quickly the paper inside could re-ignite and catch you by suprise.  
     
mussel shell showing raku glaze on enamels.The iridescence on this piece was achieved with raku.