Safety Data - Nitride-Bonded Silicon Carbide Kiln Shelves

Technical Information, Care & Use Guide for Nitride-Bonded Silicon Carbide Kiln Shelves

Kilncor’s premium nitride-bonded silicon carbide kiln shelves are designed for serious ceramic artists, pottery studios, schools, and production environments that need strong, lightweight kiln furniture. Our shelves are thin, durable, and easy to handle compared with many bulky, heavy traditional cordierite or conventional silicon carbide shelves.

Please review the following care and use information before firing. Kiln conditions, firing schedules, clay bodies, glazes, loading methods, and moisture exposure can all affect kiln shelf performance.

Surface Appearance

Each Kilncor kiln shelf may have slight surface differences. Variations in color, sheen, texture, casting lines, or manufacturing marks are normal and do not necessarily indicate a defect. The surface may also change after the first few firings. Over time, areas that become dull from glaze cleanup, kiln debris, or sanding may continue to change in appearance with use.

These cosmetic variations are expected with high-performance refractory kiln shelves and do not affect the shelf’s intended function.

Before First Use

New Kilncor shelves are ready to use when received. A special “seasoning” or break-in firing is not required.

Surface Cleaning & Maintenance

Due to the dense, low-porosity surface of nitride-bonded silicon carbide shelves, many glaze drips, clay residue, and firing debris can be removed from the surface when cleaned properly.

Remove glaze runs, halos, clay, or other residue as soon as practical. Allowing buildup to remain on the shelf may increase the chance of future work sticking to the surface.

For light cleanup, use a Kilncor GlazeFile Kiln Shelf Restoration Tool, scraper, sandpaper, abrasive cleaning block, or similar hand tool. For heavier buildup, an abrasive disk or grinder may be used carefully. Always wear proper eye, hand, and respiratory protection when grinding, sanding, or scraping refractory materials.

Do not aggressively gouge the shelf surface. Remove only the fused material or residue necessary to restore a clean working surface.

If you have any questions about surface cleaning, we recommend reaching out to the Kilcor customer service team at support@kilncor.com before cleaning or removing debris from the surface of the shelves.

Kiln Wash Guidance

We do not recommend using kiln wash with Kilncor shelves. 

Use With Existing Kiln Furniture

Kilncor shelves can be used with standard kiln posts and kiln furniture, provided the furniture is appropriate for the kiln, temperature, and load.

Avoid using overly large or massive posts that create wide contact areas against the shelf. Large contact areas can contribute to uneven heating or cooling. Full-size hard bricks are not recommended as shelf posts. Properly sized posts are preferred.

Recommended Stacking Method

A three-point stacking system is recommended. Three points create a stable plane and help reduce uneven stress on the shelf.

Four-point stacking can create stress if the posts are not perfectly level. If one post is slightly taller or shorter than the others, the shelf may rock or carry uneven load. For this reason, three-point support is recommended for Kilncor shelves.

Always make sure shelves are level, stable, and properly supported before firing.

Flipping Shelves

Unlike many traditional shelves, Kilncor’s high-performance nitride-bonded silicon carbide shelves are designed to maintain excellent flatness under normal pottery firing conditions when used properly. Regular flipping is not required.

However, users should still inspect shelves before each firing. Do not use a shelf that is cracked, been exposed to moisture, unstable, wet, heavily damaged, or unsafe.

Wet Pots, Damp Glaze & Moisture

For best results, allow greenware and freshly glazed pieces to dry completely before loading them onto the shelf. 

These shelves should be stored indoors in a dry location. Keep them off bare concrete floors and away from continuous moisture sources. Shelves should not be exposed to prolonged periods of moisture, such as rain, standing water, condensation, wet floors, or outdoor storage. Before using a shelf in the kiln, ensure it is completely dry. Any retained moisture can expand into steam as the kiln heats, potentially causing critical shelf failure during the firing cycle. For this reason, shelves should never be placed in the kiln while wet.

If a shelf has been exposed to prolonged moisture or you suspect water has entered the shelf, do not fire it normally. A controlled dry-out procedure may be required before returning the shelf to standard firing temperatures. If you have any questions or concerns, we recommend reaching out to the Kilncor customer service team before using the shelf.

Drying Procedure

Position shelves with a minimum clearance of 1 in. between each level using kiln posts. An electric kiln is recommended to ensure accurate temperature control.

From ambient temperature, heat the kiln to 190°F at a controlled rate of 50°F per hour. Maintain this temperature for 24 hours.

Increase the temperature to 210°F at 50°F per hour. Maintain this temperature for 12 hours.

Continue heating to 230°F at the same rate of 50°F per hour. Begin the 12-hour soak only after the entire kiln load has reached the target temperature.

Increase the kiln temperature to the required final soak temperature within the range of 350–500°F at a rate of 100°F per hour.

Maintain the selected final soak temperature for a minimum of 18 hours.

Upon completion of the heat treatment cycle, switch off the kiln and allow it to cool naturally to ambient temperature. Do not use forced cooling methods.

Thermal Shock & Cracking

Most kiln shelf failures are related to uneven heating or uneven cooling, also known as thermal shock. Even high-performance shelves can crack if one area of the shelf becomes much hotter or cooler than another area too quickly.

Thermal shock risks may increase when:

• A shelf is placed too close to direct flame.

• A shelf is exposed to cold air during cooling.

• Kiln ports, peeps, dampers, or leaks cool one area faster than the rest.

• Massive posts or bricks create uneven contact areas.

• The shelf is positioned directly in line with strong element heat.

• The kiln is cooled too quickly.

• The shelf has absorbed moisture.

• The shelf is used in an unsuitable kiln environment.

Avoid rapid, uneven temperature changes. Follow appropriate firing and cooling schedules for your kiln, shelf size, and firing type.

Electric Kiln Use

Nitride-bonded silicon carbide shelves may be used in many electric kiln applications when properly sized and used correctly. Because silicon carbide materials can have some electrical conductivity, extra care must be taken in resistance-coil electric kilns.

Use the correct shelf size for your kiln. The shelf should be centered and should not touch the kiln walls, elements, thermocouple, or element grooves. Make sure the kiln is in good repair and that no elements are sagging, loose, or protruding from the grooves.

Never reach into or adjust shelves inside an energized kiln. Always turn the kiln off before loading, unloading, adjusting, or inspecting shelves.

For large shelves in electric kilns, slower firing schedules are recommended. Avoid positioning large, thin shelves directly in line with element channels when possible, as uneven heating can create thermal stress.

Do not touch the kiln shelf when the kiln is in operation. The kiln shelf should only be handled when the kiln is completely turned off. 

Gas, Soda & Wood Kiln Use

Kilncor shelves may be suitable for many gas, soda, and wood firing applications, but placement matters.

Avoid direct flame impingement, especially early in the firing. Do not place shelves where flame will strike one area of the shelf directly before the rest of the shelf has heated evenly.

In wood kilns, avoid high-risk areas such as fire mouths, areas near checker walls, or locations with strong uneven flame exposure. In these areas, thicker conventional silicon carbide shelves may be more appropriate.

In soda firing, avoid spraying liquid soda solution directly onto the shelf through a port. Direct liquid contact can cool one area suddenly and create thermal shock. Soda should be introduced in a way that disperses through the kiln atmosphere rather than striking the shelf directly.

Raku Use

Kilncor shelves are not recommended for raku firing. Raku kilns often create fast, uneven heating and direct flame exposure, which can cause thermal shock. We recommend using kiln furniture specifically suited for raku conditions.

Why Nitride-Bonded Silicon Carbide Kiln Shelves Cost More

Premium nitride-bonded silicon carbide kiln shelves cost more than many traditional kiln shelves because they are made from advanced refractory materials and manufactured for strength,, flatness, and long-term performance.

Compared with many standard shelves, they are thinner, lighter, easier to handle, and designed to provide more usable kiln space. Their lightweight design may also reduce the amount of energy spent heating heavy kiln furniture.

For frequent firers, schools, studios, PYOP business owners and production potters, the value is not only in the shelf itself, but in easier loading, more efficient kiln stacking, reduced handling strain, easier cleanup, and long-term performance.

Important Safety & Use Disclaimer

Kiln shelf performance depends on proper use, kiln condition, firing schedule, clay body, glaze chemistry, load distribution, storage conditions, and handling. No kiln shelf is indestructible.

Inspect shelves before each firing. Do not use shelves that are cracked, damaged, unstable, or unsafe. Store shelves dry, avoid thermal shock, follow proper firing practices, and test clay/glaze combinations before firing valuable work directly on the shelf surface.

When unsure, contact the Kilncor customer service team at support@kilncor.com, the kiln manufacturer, shelf supplier, or a qualified kiln technician before use.

Warranties

All kiln shelves are sold as is. No warranties are expressed or implied. 

Customers are responsible for inspecting their shipment immediately upon arrival. Any shipping related damage must be reported within 24 hours of the package being marked as delivered by the carrier's tracking information. 

Chips, firing marks, pinholes and other factory flaws are not considered as damage. 

To submit a shipping damage claim, customers must:

• Notify us within 24 hours of the recorded delivery

• Provide clear images of the damaged product, the packaging (including the shipping label) and any visible damage. 

• Email documentation to support@kilncor.com 

Claims submitted after the 24 hour reporting period or without sufficient photographic documentation will not be eligible for review.