All fired up: Ignite the passion in your pots
3 November 2015
With the arrival of BBC Two's The Great Pottery Throw Down, we here at Get Creative HQ could practically hear the sound of a thousand potters' wheels begin to squeak. What better time to share the first of three inspirational pieces on pottery. MERCEDES SMITH shares some fascinating firing techniques loved by professional potters. Alcohol is involved in at least two methods so please, pot responsibly!
If you think pottery is all about mastering the precision skills of slabbing and throwing you’d be wrong.
These things are only the beginning of the pottery process, and though they will take up much of your time on that fantastic beginner’s pottery course you’ve been planning to sign up for, (why haven’t you signed up for it yet by the way?) there is a great deal more to the ceramic arts.
The really exciting part of the pottery process lies in embracing various glaze effects, and mastering the endless potential of atmospheric kiln techniques, some of which are incredibly simple to achieve.
If you want to know what an education in ceramics has in store for you, let us inspire you with a few of our favourite, fabulously creative firing effects:
Wood Firing: For the purists among you
Kiln firing pots with wood and flame is, as you would expect, one of the more traditional techniques in ceramics, nudged aside somewhat in the 20th century by the introduction of gas and electric kilns.
But wood fired pots still hold a revered place in pottery, and have a special beauty all their own. When wood firing, you don’t need to glaze the outside surface of your pot because the super-heated wood ash which fills the kiln settles on the ceramic surface and creates its own, gorgeous glaze.
The various glaze effects you can achieve depend on the type of wood and the type of clay you bring together, and as flames touch the surface of the pot, they cause chemical reactions, resulting in unusual colours and wonderful effects.
Results are delightfully random, but with experience, you can learn to control things to some extent depending on where pots are placed in proximity to the fire.
Horse Hair Reduction: For cowboys and non-conformists
This technique sounds hard on the horse, but relax, he need only endure a light tail trim.
a craze of irregular lines can be achieved by holding clumps of hair against the burning surface
It will, however, subject you to smoke and the pungent smell of burning hair, but if you can bear it the results of this technique are quite beautiful, and vary between what you might call a Cy Twombly and a Jackson Pollock effect.
A super smooth, unglazed pot is fired to a high temperature and then removed carefully from the kiln.
Individual horse hairs are then draped across the pot, and as the hairs burn away on the hot surface, they create sharp, grey-black lines of carbon which become graduated as the smoke drifts in the direction of the hot airflow.
Single lines are stylish, but a craze of irregular lines can be achieved by holding clumps of hair against the burning surface. Once cooled, the pot can be waxed to seal in the beauty of these curious, calligraphic markings.
Salt and Soda Firing: For ‘laissez faire’ types
The perfect technique for those who put their faith in happy chance, salt firing is a vapour-glazing process, in which salt is introduced into the kiln when it is at a very high temperature.
The intense heat vaporizes the salt instantly, and sodium vapour combines with silica in the clay to form a hard glaze which gives a distinctive ‘orange peel’ texture to the surface of the pot and causes incidental blushes of subtle colour.
Soda firing is the less toxic, and more up to date equivalent of salt firing, where a solution of soda and water, instead of salt, is sprayed into the kiln as it reaches peak temperature.
The lovely colours and richly dimpled surface textures you can achieve with salt and soda firing, along with the sheer unpredictability of results, makes this one of the more exciting surface techniques available, and it is used to astonishingly beautiful effect by a host of contemporary potters.
Stone Explosion: For anarchists
Risking the very life of your pot seems counterintuitive, but hey, who doesn’t occasionally enjoy the twin delights of wilful destruction and new order.
‘Stone explosion’ or ‘ishihaze’ would normally occur by accident when impurities such as sand or small stones in the body of the clay burst through the surface of the pot during firing.
Recently, however, it has become a deliberate technique, where grit, small pebbles or large stones are added to the clay to encourage entirely random and potentially beautiful effects.
Grit laden ishihaze glazes will subtly rupture the surface, while the inclusion of larger stones can result in fabulously interesting cracks or part of the pot literally being blown apart.
This technique has also been extended, as demonstrated in some impressive international shows this autumn, to the inclusion of chunks of precious metals such as gold and platinum, which are pressed into the surface and then pop and ooze rather deliciously through the clay.
Raku Firing: For risk takers
Raku is an ancient Japanese art form, but has undergone some rather ‘explosive’ westernization in the last hundred years.
With Raku firing, you alternate between overdosing and then depriving the atmosphere around the pot of oxygen, which creates sudden flashes of different colours across the glazed surface.
A raku glazed pot is fired to red hot at a faster rate than is typical, and when the trained eye judges glaze firing complete, the pot is immediately removed from the kiln and plunged into a container of combustible materials, such as sawdust or paper shreds.
The container is then quickly sealed, and the resulting fire consumes the oxygen within.
After a few moments the container can be opened briefly to allow the oxygen back in and, depending on whether you have your timings right, you will either lose your eyebrows or see the colour change suddenly across the surface of the piece before you reseal it to ‘capture’ the colour.
Copper Matt Alcohol Reduction: For your inner pyromaniac
It goes without saying that fire and alcohol are a volatile mix so this technique carries a serious safety warning.
The process is dramatic, so if you’re the type to get nervous when your dinner date orders a crepe suzette, this is probably not for you.
In essence it is another Raku reduction technique that involves a red hot pot and a sealed chamber, but with one significant addition to the process.
It begins with a piece that has been fired with a copper wash, and again, at the correct temperature the piece is removed from the kiln.
Rubbing alcohol is then sprayed directly onto the pot and, well, you can imagine the fireball that erupts next.
Spectacularly risky it might be, but it is also great fun to watch, as multiple colours dance across the flaming pot before it is put into a sealed chamber, let breathe again, and resealed as a riot of colour imprints on its surface.
Iridescent Lustre Fuming: For extravagant types and big spenders
This truly beautiful technique has its roots in the art of glassblowing, and results can vary from a rich copper glow to a dazzlingly prismatic rainbow finish.
It is another of the vapour-glazing techniques, where a metallic salt like tin chloride is introduced into the kiln at a low heat and allowed to swirl around the pot, though fumed applications of platinum, gold and other precious metals can also been used to great effect if you have that kind of budget to play with.
Lustre fuming works well on a wide variety of pre-glazed surfaces. Particularly lovely are the mother-of-pearl effects that can be produced on top of white or very light coloured glazes, and the fabulously vivid iridescence that occurs when a base glaze of precious metals has already been applied.
The brilliance of colour achieved never fades, so be warned, a pot with a personality this strong won’t tolerate competing colours and demands a plain white room.
Pit Firing: For surfers and beach bums
Pit firing, which results in highly colourful ‘flame painted’ pottery, is the original, centuries old method of ‘baking’ clay, yet has thoroughly modern appeal when you combine it with some old uni mates, a twelve pack of beer and an early evening trip to the beach.
even cow pats have been shown to yield a range of spectacularly beautiful surface colours.
Quite simply, you dig a deep pit in the sand, and pop in your pots along with heaps of combustible material, before setting fire to it all and building a raging bonfire on top (cue beer).
When packing your pit, twigs, leaves, straw, sawdust, wood and paper are all sensible choices and will have varying effects on the clay, but unusual materials such as pine needles, seaweed, banana peel, coffee grounds and even cow pats have been shown to yield a range of spectacularly beautiful surface colours.
Do remember your sleeping bag, however, because it will be morning before you can safely remove your pots from the pit and admire your work.