There are lots of variations on the Coil-Building method. This one avoids all the pit-falls that cause your pots to go out of shape or break in the kiln.
I started out as a Coil-builder 34 years ago and I still turn to it regularly. All my monumental brick sculptures are coil-built. It’s all about understanding the clay and how joins are actually formed. The skills you gain from coil-building are extremely transferable making it a great place to start for beginners. There is a lovely rhythm to the work.
Here is the Coil-building Workshop that I run at Osprey Studios. Many thanks to my lovely students for being in these pictures.
How to do excellent Coil-Building.
Choose a clay with a medium to high percentage of multi-grade grog ( grit in different sizes from dust to medium sized bits). Scarva ES 50 Crank is ideal. Clays of this type will give you the best results.
Very important bit.
Genuine joins are formed when the chains of platelet-shaped particles from each section inter-lock. Imagine a magnified image of tangled hair.
Score marks do not give the surface ‘tooth’; they allow water into the clay-body. On vertical surfaces score marks and slip hold the water in place to give it time to sink in.
Slip is not ‘glue’. It is clay particles spread out in water and has little strength, especially when it has dried. It is ideal for holding a lot of water in place to give it time to be absorbed to soften the area of leather-hard clay.
Never use a needle tool. Your score marks will be too narrow and deep. They will get covered over, resulting in a ring of tiny but malevolent air-bubbles that will expand in the firing and a crack will zing along the joins. I have fired pots for poor, misinformed makers that have come apart at every coil! You could see the deep score marks and powdery slip.
Every join is an opportunity for a crack, every coil a point where you might loose control of your shape. So it makes sense to use coils that are large enough to handle well and will give you 4cms of height.
Rolling your coil on the table can cause 2 problems;
- The grog that would have helped create an excellent join is packed towards the centre of the coil and the finer particles of clay are packed together to form a ‘skin’ of tight platelet shaped particles that are reluctant to reach out and bond with the platelets of the pot.
- enthusiastic rolling often causes a tunnel to form at each end of the coil that would be a substantial, damaging air-bubble. This is why you often see coil-builders break off both tips of their coils with out even looking at them; they know that hazard is probably there.
Do not be tempted to push clay down the pot with this step. Go to the end of your coil and stop. Do NOT go up another layer!
The over-hang of the coil can trap air if hastily pressed down. Rushed building is why coil-pots have a very unfair reputation for being hideous.
Coils are perfect for all sorts of applications.
When you are making complicated shapes use temporary supports made of clay that will shrink with the form. Build in support walls and buttresses. Use rigid supports with care: plan to accommodate the shrinkage.
30.Note the finger marks left by the process: these are just like the marks of a serrated-kidney on a smaller pot. Like corrugation, they add strength to the wet clay wall and will be left on until the clay is firm enough to hold it’s shape.
The same layer of the fired panel-sections of Bruce during installation.
Here’s some good examples of rigid supports in action:
Adding clay on to the surface.
38.All the big coiled sculptures have artwork added onto the surface once it is firm. Exactly like the smaller pot, the area is softened using scored ‘ditches’ and slip to hold the water in place, allowing it to soak in to the firm clay and raise up those platelet shaped clay particles ready to join with soft clay.
Once a good join is achieved the added clay is modelled and carved in stages as the clay firms up. The drying ( and shrinking) is kept slow using plastic covers to allow that vulnerable join to set as the water moves from the soft added clay into the firm wall.
Remember that water will always want to be level and will travel down the form over time as well as evaporating from the surface. This passage of water past those platelets completes the join. If there is too much water it will collect and run down the join, destroying the bond.
With that in mind add as much clay as your artwork needs. If it becomes more that 2 cm thick hollow it from the inside even if this means cutting the section out of the form, hollowing it and reassembling it. The important thing is to find a way to get the look you want. For advice on this process click here: Working solid and hollowing sections out.
Drying coil-built forms.
39.Use plastic to shield firm parts from drying while you work on new parts. e.g. a strip of plastic sheet to keep the top edge soft while you put art-work on a lower area before it gets to hard. And visa-versa.
Slow the drying as much as possible to allow all those joins to set using plastic sheets.
Cover the piece in a shield of newspaper ( 5 sheets thick) or a cardboard box or fabric sheets (not wet) to create a damp micro-climate that will slowly release the water from the clay and protect from drafts that would cause un-even drying (and maybe, consequently, cracking)
Related info on this site.
For a full description of how the really big sculptures are done click here: Building Brick Sculptures on a monumental scale.
The whole story of the fab Gwalia Mynydd Mawr Care and Nursing Home Courtyard Sculpture designed with local primary school children and staff and residents of the Home, run by Arts Care Gofal Celf in Carmarthen, Wales: Studio Diary, The Tumble Commission, parts 1-8.
Using clay armatures and coils: How to Make a Head: Clay Armatures and Building Hollow.
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