Making Your Own Kiln Shelves from Scrap Parts

A kiln shelf has a demanding job: it must carry the weight of pots at high temperature, stay reasonably flat, resist glaze drips and survive repeated heating and cooling. That makes scrap a useful resource, but only when the salvaged material is genuinely kiln-rated. Ordinary tiles, concrete pavers, glass, metal and unknown refractory board can crack, warp or release harmful substances inside a kiln.

For Australian potters, reuse can reduce the cost of setting up a home studio. Shelves are expensive to ship to regional areas, and a sound second-hand piece may be available through a local pottery club, Gumtree, Facebook Marketplace or a ceramic supplier in Melbourne, Sydney, Brisbane or Perth. The key is to inspect every part carefully and build around safety rather than saving a few dollars.

Choose Suitable Refractory Materials

Look first for intact cordierite or mullite kiln shelves, kiln furniture, refractory slabs and sound pieces of high-temperature kiln board. These materials are designed to tolerate thermal shock. A shelf that has been used in a pottery kiln is generally a better candidate than a piece of industrial refractory material with no known firing history.

Avoid anything that contains cement, resin, fibreglass, paint, insulation foam or metal reinforcement. A pale ceramic-looking panel is not automatically suitable for a kiln. Ask the previous owner about its maximum firing temperature and whether it has been exposed to glaze, salts or unusual chemicals. For stoneware, aim to match the shelf’s rating to the highest temperature you plan to use rather than relying on appearance.

Small cracks deserve careful judgement. A hairline crack through an otherwise sound shelf may remain useful for test tiles or tiny loads, while a crack reaching an edge can open during firing. Never bond a broken shelf with household adhesive. Most glues burn away, contaminate the kiln chamber or produce a structural failure at heat.

Measure the Kiln Before Cutting

Measure the internal width, depth and height of the kiln, including the space required for posts and ventilation. Leave enough clearance around the shelf for air movement and expansion. A shelf that fits cold may jam when heated if it touches the walls, heating elements or lid.

A practical scrap-built shelf can be made by trimming a larger kiln shelf into a smaller piece with a diamond blade, or by arranging several narrow, kiln-rated sections over stable posts. A continuous surface is preferable for glazed work because joints can catch drips and create uneven support. If you must use sections, keep the joins away from heavy pots and ensure each piece has independent support beneath it.

Measure twice before making a cut. In Australia, replacement cordierite shelves can be costly once freight is added, especially to Tasmania, regional New South Wales or remote Queensland. A cardboard template helps you test the dimensions and reveals whether the proposed shelf will block the peepholes or interfere with the kiln’s element grooves.

Cut And Finish With Dust Control

Use a diamond masonry blade and work outdoors or in a well-ventilated area. Wet cutting is preferable because refractory materials can contain crystalline silica. Do not dry sweep dust from a studio floor. Use a suitable vacuum rated for fine hazardous dust, damp-clean surrounding surfaces and follow the safety information supplied with the material.

State and territory workplace rules differ, but silica exposure is a serious issue in Australian studios, including home garages and community spaces. Wear eye protection, hearing protection and a properly fitted P2 respirator when cutting or handling dry dust. Keep children, pets and other makers away from the cutting area, and change dusty clothing before entering living spaces.

After cutting, smooth sharp edges lightly with a diamond pad. Do not aggressively grind the shelf surface, since a thin or uneven section may warp. Clean the finished piece with a damp sponge and allow it to dry fully. A small test firing without pottery can reveal loose grit, odour or movement before valuable work is loaded.

Build A Stable Support System

Kiln posts should be kiln-rated and matched in height. Arrange them in three or four-point patterns according to the shelf size, with the posts aligned vertically between levels. Staggering posts can transfer weight onto unsupported areas and increase the chance of cracking. A long shelf may require additional central support, but too many posts can restrict heat circulation.

Keep posts away from heating elements and ensure no shelf edge presses against the kiln wall. Check that each post stands flat, without glaze stuck to its base. Kiln wash can be applied sparingly to the shelf surface to make accidental glaze drips easier to remove, but it should not be painted onto element grooves or applied as a thick, flaky layer.

For a reclaimed shelf, mark the usable load area with chalk and place heavier pieces near the support points. Leave room for tall forms and make sure the top of the load will not touch the kiln lid. A simple dry assembly, with the kiln switched off, is the safest way to confirm the layout.

Test The Shelf Before A Full Firing

Start with a low-risk firing containing test tiles, bisque pieces or inexpensive small forms. Heat gradually through the lower temperature range and listen for unusual movement or cracking. Once cool, inspect the shelf for new fractures, bowing, powdering or glaze contamination. Never open a hot kiln to investigate a sound.

If the shelf survives, use it gradually rather than loading it to maximum capacity at once. Record the firing temperature, shelf position and approximate load weight. This record becomes useful when deciding whether a scrap-built shelf is appropriate for earthenware, stoneware or a particular glaze schedule.

Kiln installation also requires attention beyond the shelf itself. Electrical kiln connections should be checked or completed by a licensed electrician under the applicable state or territory requirements. Gas kilns need competent installation, ventilation and compliance with local gas and fire rules. Contact the relevant council or WorkSafe authority before converting a garage, shed or shared studio, particularly where fumes, neighbours or combustible materials are involved.

Make The Shelf Part Of Studio Practice

A well-made shelf can support a slower, more attentive workflow. Cleaning the surface, checking each post and arranging a balanced load creates a useful pause before firing. That kind of deliberate routine connects with clay and mindfulness, especially when making is treated as an observation practice rather than a race to fill the kiln.

The shelf can also become part of an experimental setup for decorative plates, small sculptures and abstract pieces inspired by coastlines, leaves or weathered rock. Keep textured work elevated on stilts or sacrificial tiles where necessary, and remember that glaze can run through pinholes or cracks in a reclaimed surface.

For artists interested in how ceramics meet exhibition-making and contemporary practice, Gestalt Projects offers a useful point of reference. A carefully documented firing, including the shelf material and kiln schedule, gives future buyers or workshop participants greater confidence in the work’s production history.

A scrap-built kiln shelf should be treated as a tested studio tool, not an invisible shortcut. Label it with its dimensions, material, known temperature limit and any visible repair history. Retire it when cracks spread, the surface begins to crumble or the shelf develops a noticeable bow.

At Amelia Creations, practical making sits alongside shared creative experiences. If you are planning a small Australian studio event, ideas from hosting a clay and wine workshop can help you organise tools, surfaces, refreshments and firing expectations clearly. Participants should always know that their pieces may change during drying and firing.

Local material knowledge is valuable as well. Potters working around Barcelona can explore local clay bodies, while Australian makers can compare regional clay suppliers and firing ranges before choosing a body. Build the shelf conservatively, test it patiently and let every firing provide evidence for the next one.

Begin with one sound reclaimed shelf or a small kiln-rated section, prepare a safe cutting area and keep a record of the test firing. Share the finished work through your studio portfolio or mailing list, and use each successful firing to develop a more reliable, resource-conscious ceramic practice.