Kiln Shelves 530mm x 530mm x20mm

SELECTION OF SHELF THICKNESS
The selection of shelf thickness is governed by the following factors:
1. The maximum temperature
2. The time held at that temperature
3. The size of the shelf
4. The atmosphere conditions - i.e. reducing" or "oxidising"
5. The average load to be supported
6. The distance apart of the props
7. The amount of bending that can be tolerated during the expected life of the shelf
The following guide will be helpful until a more accurate determination can be made in light of experience.

Biscuit & Earthenware 980 - 1120°C
Small shelves or light loads - 8mm, 12mm or 15mm thickness
Larger shelves or heavy loads -20mm thickness
Stoneware 1280 - 1300°c 20mm thickness
Above 1280°C, especially under re¬ducing conditions, we do suggest 20mm thickness (minimum).

Bending

Most shelves will ultimately bend if heavily loaded and used at high temperatures. Where conditions of reduction are experienced the shelf may bend more quickly. Under these conditions a compromise is often necessary.

Cracking
Generally speaking, a shelf should not crack. If a shelf does crack the cause should be sought and eliminated if possible. The following causes may be the reason for cracking:
1. Too rapid cooling, particularly at 200 - 600°C.
2. Uneven heating or cooling, possibly due to poor circulation or uneven loading of ware.
3. Bad propping

Props and Propping
1. Three props are better than four, being inherently stable.
2. If four props must be used make sure that they all touch the under side of the shelf above.
3. Props should be placed in line vertically. Ensure that the end faces of the props are flat and parallel.