The arrival of spring always makes me want to get out into the garden, and on my list of things to make for many years has been a rhubarb forcer. Although it may not be a ‘must make’ for everyone, the process can be easily adapted to make other items, either for the garden or the home. Jacqui Atkin
This was first published in issue 13
You will need:
A grogged earthenware or stoneware clay (like crank) – Forcers are most commonly thrown in red earthenware clay, but stoneware is more durable and weather-proof.
A sprig mould (optional for surface decoration)
TIP: You’ll find it much easier to maintain the shape of the form if you build it on a large, round wooden batt. If your batts are square, draw a large 30-40cm-diameter circle on one, using a marker pen for a clear outline.
Place the batt on a whirler.
If your kiln is round, you could also build the form directly on the kiln batt, to save having to move it later.
Start by rolling a thick coil, long enough to fit the circumference of the batt.
On a sheet of plastic, flatten the coil in a straight line along its length, holding one end in a slightly elevated position as you work along the surface with the heel of your hand.
When finished, lift the coil, turn it over then flatten it again to an even thickness.
Position the coil on the batt in an upright position about 3cm from the edge if working on a round – fit it to the drawn circle if not.
Overlap the ends of the coil and cut through both on a diagonal with a knife.
Join the ends together with some slip, making sure the clay is blended in well, inside and out.
Score the rim of the coil with a serrated tool, then roll another coil in the same way as the first.
Apply some slip to the rim.
Join the second coil onto the first, pushing it down well with your fingers to ensure the seal is good.
Roll two long thin coils of soft clay and reinforce the join on the inside and outside.
Blend the coils in well, then scrape back the surface with a kidney to remove excess clay and lumps and bumps.
Tip: if you have a rectangular scraper, stand it on the batt on the outer edge of the form and draw it around the circumference. This will ensure the wall is straight while neatening.
Flatten the third coil into a slight curve then position the wider, outer edge of the coil on the form so that it curves in very slightly. Join the ends and reinforce as for all the other coils.
Continue to build the form upwards in this way, narrowing at the neck until the opening measures 25cm and the form is about 60cm high – or your preferred size.
Roll and flatten a final coil, this time in a straight line, and apply it to the rim.
Scrape away all excess from the reinforced joins and smooth over the surface.
Level the rim with a surform then smooth over the surface with a rib – bevel the edges slightly as you do this, or run your fingers over the rim to soften the edges slightly.
To make the lid, first measure the circumference of the neck of the form and cut out a circular card template 10mm wider than the measurement, or use a plastic lid as shown here – see tips box.
TIP: I keep lots of round container lids, in many sizes, for jobs like this where a round measurement needs to be taken. If you collect enough, you’ll usually find you have one that’s the perfect size. You can then use the lid as a template for cutting out. If you have a range of lids or circular discs, it will help to build your form to accommodate one of them – it will save having to make extra templates and take measurements.
Roll a slab of clay 5mm thick and cut out the circle using the template as a guide. If you used a lid, as shown here, mark the circumference of the circle with a pin, then cut it out 10mm larger to accommodate the extra width advised for a card template.
Transfer the slab to a circular board if you have one, and place on a whirler.
Smooth around the edge of the circle with your finger to round and soften it.
To make the dome of the lid, you have two options
1: If you have a bowl mould with a rounded base, use it to make a shallow dome for the lid, as shown, filling the mould to a third of its capacity with a slab of clay. Gently press the slab into the mould with a barely damp sponge, then allow the clay to firm to leather-hard in the mould.
2: Pinch a dome for the lid from a ball of clay – slightly more difficult than the mould option, because the form will be quite wide and shallow. Pinch it in stages, firming the clay periodically with a hairdryer to maintain the shape. Scrape over the surface with a kidney, both inside and out until the thickness of the wall is even, then level the rim with a surform.
Position the dome centrally on the pre-cut circle of clay and mark its position with a pin.
Score and slip the rim of the dome and the marked position, then fix it in place, pressing down gently but firmly to ensure it adheres to the base.
Run a rib or wooden tool around the dome to remove excess slip, but also to define and neaten the shape.
Now measure the internal circumference of the rim of the forcer to gauge the position for the flange of the lid. Again, use a plastic lid if you have one the correct size, otherwise cut out a template as before, fractionally smaller than the measurement.
Turn the lid over and support it on something that won’t distort the shape, like a piece of thick foam.
Position the template centrally on the underside of the lid and mark the position with a pin, then score within the line where the flange will fit.
Roll and flatten a coil of clay long enough to fit the circumference of the marked position on the lid and cut it to a 20mm width.
Slip the marked position on the lid, then fix the coil in place, as shown, making sure it seals to the surface well. Overlap the edges and neaten the join as you did when building the body of the forcer.
Reinforce the join on the outside and inside of the flange with a coil of soft clay, then use a rib to neaten the reinforcement.
Use something round to lightly score a circle inside the flange – a roll of tape is useful, or a cookie cutter – use whatever is most readily to hand.
You are cutting through the first layer only, to reveal the inside of the dome. Be careful not to cut too deep. Cut out the scored circle with a knife, then neaten up the cut edge inside the lid with a rib or tool, to remove sharp edges.
Sit the lid on the forcer then make a knob for the top by pinching a small ball of clay to your chosen shape.
Hollow out the knob a little, using a hole-cutter if it’s on the large size. Solid lumps of clay can be troublesome in firing, so are best avoided where possible.
Mark a central position for the knob, then make a pin hole at the centre
Fix the knob in place in the usual way, after scoring and slipping. Remember to neaten around the knob to remove excess slip.
Cut a hole through the dome of the lid to the knob, from the inside, using a hole-cutter.
The forcer is now essentially finished, except for surface decoration.
Make a series of sprigs by pressing a slab of clay into the mould then scraping away the excess with the side of a wooden batten.
Score the backs of the sprigs with a serrated tool, before lifting out of the mould with a ball of soft clay, as shown.
Place the sprigs on the forcer in your chosen arrangement – they should stick to the surface temporarily while you decide on their position.
When happy with the position of the sprigs, draw around each one with a pin then score the marked positions.
Apply some slip to the underside of the sprigs, then fix them in place pressing them on gently but firmly, to ensure there’s no air trapped on the undersides and excess slip is squeezed out.
Neaten around each sprig with a modelling tool.
Finish the surface of the forcer in your chosen way – here the surface has been divided by scoring two lines through the arrangement of sprigs then texturing with a serrated kidney above and below the lines, but you could leave it smooth if preferred.
Texture the lid in the same way as the body, then neaten around the edges with a wooden tool to remove burrs of clay.
Allow the forcer to dry slowly, with the lid in place, before bisque-firing.
After bisque-firing, cover the surface of the forcer in either a glaze or oxide wash, as shown here, then fire it to the clay’s optimum temperature.