There's a particular quiet in a studio just before a firing. The shelves are stacked, the lid is down, and everything that could still be changed is behind you. It is a good moment — unless you notice, four hours later, that a glaze-heavy bowl is sitting barely a centimetre from an element, or that the bottom shelf is propped on a cracked prop.

A kiln load takes hours you cannot get back, along with the ware inside it. The checks below take about ten minutes. Run them in the same order every firing and you will catch the small mistakes while they are still small.

Start with the room, not the kiln

Before you carry a single pot across the studio, look at what surrounds the kiln. Aerosols, solvents, white spirit, paper, plastic buckets and offcuts of foam have no business within a couple of metres of a hot kiln. Check the floor as well: a kiln standing on a wooden bench or a plastic-topped table is an accident waiting for a reason to happen. It belongs on a proper kiln stand or a solid, non-combustible surface.

• Open a window or door, or switch on the extraction you normally use. Firing in a sealed, unventilated room is unpleasant at best and genuinely risky at worst.
• Check the plug, lead and isolator for damage, scorching or a loose fit. If anything looks tired, replace it before firing rather than after.
• Keep an appropriate fire extinguisher within reach and know how to isolate the power quickly.
• Clear the area above the kiln. Shelves and cupboards directly overhead collect heat and dust.

Your kiln manufacturer's instructions always come first. If they specify clearances, ventilation or a particular stand, follow those over anything you read elsewhere, including here.

Inspect the kiln itself

Elements and interior

With the power off, look along the elements. You are checking for sagging coils, bright or discoloured spots, a broken length, or an element that has dropped and is touching the brickwork or a shelf. Any of those means the kiln needs attention before it goes on. A quick visual pass now is far cheaper than a failed firing or a scorched element.

Bricks, lid and door

Cracks in firebricks are normal; missing chunks, especially around the lid rim and the door opening, are not. Check that the lid sits flat and the catch or hinge pulls it down evenly. On a front-loading kiln, look at the door seal and the condition of the brick edge it presses against. Gaps let heat escape and cause uneven firing, particularly near the top of the chamber.

Sensors and controls

Check the thermocouple sheath for cracks and make sure the tip is positioned correctly — not touching an element or a brick. If the kiln has a kiln sitter, inspect the sensing rod and tube, and keep spare firing rods to hand. Confirm the controller is reading room temperature sensibly before you programme anything.

Prepare shelves, props and kiln wash

Shelf preparation is the part most people rush, and it is the part that ruins pots. A flaking coating of kiln wash will drop onto glazed surfaces; a shelf that has soaked up a glaze drip will fuse to the next piece placed on it.

• Kiln wash: scrape back any flaking or bubbled areas, then recoat thinly and let it dry completely before loading. Thin coats work better than one thick one.
• Shelf condition: rock each shelf on a flat surface. A shelf that wobbles is warped and will make everything above it unstable.
• Props: match heights carefully and discard any that are cracked, chipped or stacked on top of each other to make up height.
• Levelling: support the bottom shelf on at least three props, with wadding or washers under the posts if the kiln floor is uneven.

Know what is going in — and what is not

Everything on the shelf should be bone dry. Greenware that still feels cool to the cheek will steam and crack. Glaze should be dry to the touch, with the base and any foot ring wiped clean of drips and runs. If a glaze has pooled thickly in a well or on a rim, expect it to run; fire it on a waster slab or leave it out.

Avoid mixing clay bodies that need different top temperatures in the same load, and be honest with yourself about anything you are unsure of. Unknown found objects, glass, metal inclusions and heavily repaired pieces belong in a separate test firing, not in the middle of a full shelf of commissioned work.

Place ware with clearance and balance in mind

Air needs to move through the chamber. A kiln packed like a removal van will fire unevenly, with hot spots near the elements and cold pockets in the centre of dense clusters.

• Leave a clear gap between ware and the elements or brickwork — a couple of centimetres at minimum, more on a powerful kiln.
• Stagger pieces rather than lining them up in solid walls, so heat can travel upward around them.
• Put heavy, thick or slow-firing pieces lower and closer to the middle. Delicate work and thin porcelain go nearer the edges where the rate of change is gentler.
• Keep stacked glazed work to a minimum. If you must stack, make sure glaze cannot touch glaze.
• Leave enough headroom for a cone pack and a little air beneath the lid or door.

Load the kiln, then stop and look at it from a step back. Anything that wobbles when you nudge the shelf is going to wobble more when things expand.

Set your cones and leave a record

Pyrometric cones tell you what actually happened, not what the controller believes happened. Place a three-cone pack — one below, one at, one above your target — where you can see it through a peephole if the kiln has one. Add a second pack near the bottom if the kiln fires unevenly top to bottom. Note which shelf each piece sits on, and write the load down: clay body, glaze, cone, date.

Last checks before you press start

1. Lid or door closed properly, with the catch engaged and no stray ware caught in the seal.
2. Peepholes plugged, or left open only if your normal practice requires it.
3. Controller programme confirmed — ramp, top temperature, hold and cooling.
4. Timer or delay set correctly if you are using one.
5. Shelf, kiln and props photographed or written into the log.

Stay within earshot for the first hour. Most problems announce themselves early: a smell, a clicking element, a controller that has dropped out. For anything electrical, if you are not confident and competent to work on it, call a qualified electrician rather than experimenting.

Keep a firing log

The most useful checklist is the one with your own results in it. Note the load, the cones that bent, the pieces that ran, and where in the kiln they sat. After a few firings you will know that the back-left corner runs hot, or that your celadon needs a slower cool, and you can adjust the load instead of guessing.

Ten minutes of checking before you press start is the cheapest insurance a pottery studio has. Do it in the same order every time, and firing day becomes a calm, predictable part of the week rather than a gamble.

Photo: LubosHouska / Pixabay