Kiln Patch – a mixture of brick dust and sodium silicate – is designed to patch the top of the kiln slab (kiln floor). This becomes necessary when clay or glaze drips onto the slab and has to be chipped out. Patching these voids allows shelf posts to sit with more stability. Kiln Patch can also be used to repair the top face of the top row of bricks (although in some cases, Kiln Cement is a better solution). Not for use on vertical surfaces.