Potters who burnish are often asked, ‘what glaze is that?’ by admirers of their objects. Naturally everyone assumes that all pottery is glazed, and that the glossy surface of a burnished pot seems like a glaze. A burnished pot has a glow from within and a warmth that glazed pots don’t have.
Burnishing is simply polishing a pot by rubbing the surface with a smooth object. There are two techniques to burnish a pot: 1- rubbing the clay with a polished stone or other smooth object 2- coating the pot with terra sigillata and rubbing it with a soft material such as a chamois-leather.
Steps to burnishing with a polished stone or silver spoon.
Step 1: Wet the entire leather hard pot inside and out. Using your finger wet the rim and the outside of the pot and the inside evenly. Work the water in well. Rub the stone on the dampened area.
Step 2: once the inside rim of the pot is burnished well then wet the top of the pot and the lip and burnish it well. Be careful the lip may be fragile and difficult to burnish. As you are burnishing some clay will collect on the surface, remove that to avoid it scratching the pot and clean the stone from clay with a towel.
Step3: After the rim and lip are finished, continue burnishing in a spiral manner to the bottom of the pot. When you dampen a new patch to burnish, slightly overlap the previous area. If the burnished area has not changed color then it is safe to go over, if it changes color then it means it dried and you could scratch the pot. It is easier to burnish in a circular motion.
Step4: Once you have finished burnishing even the foot of the pot, cover the whole pot with vegetable oil. Lightly cover the pot from the outside by placing your hand inside the pot so you don’t touch the already burnished surface. With the oil dry on the surface, re-burnish the pot with the stone. Avoid the wet oil area and wait and remove with your finger the extra oil if necessary before burnishing.
Step5: The burnished pot can be decorated by slip or incising and the fire the pot to cone 018 or 700 degrees centigrade. Firing higher than that will dull the clay and the burnishing effect may be reduced or lost.
Have fun burnishing your pots or sculptures.