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Kiln Brick Installation Guide for Mixing Ratios

A brick kiln is one of the oldest crafting tools, used to fire pottery at high temperatures. The bricks hold the heat inside the kiln and should last for many years. Kilns use an unusual mixing ratio for the mortar used to hold the bricks in place. This mixture is dry pack mortar, commonly called "deck mud," mixed with tiny bits of charcoal, referred to as "charcoal fines."

Design
- There are many sizes and shapes of brick kilns, but for many of them the basic design is a round dome, typically about 10 or 20 feet across, with two openings, one on either side of the kiln. The openings are positioned to catch a cross-breeze during the use of the kiln. The bricks are stacked up into an igloo-like shape, creating an insulated hemisphere that holds in heat to dry pottery. This kiln design has been used for thousands of years.
Mixing Ratios
- The only material mixed for the kiln construction, once you have the bricks, is the mortar used to hold the bricks together. You can vary the mixing ratio, but a mixture of five parts sand and one part Portland cement is one of the most effective. If the mixture seems too runny or grainy, try a mixture of four parts sand and one part Portland cement. Add enough water to create a thick paste, similar to that of peanut butter. Add one part charcoal fines to insulate the kiln.
Laying Bricks
- Bricks are laid end to end around the circular pattern. The bricks are laid directly on top of each other for about five or six rows. At the openings, the bricks are laid perpendicular to the circle bricks to create a sturdy doorway. The sides of each doorway should be about three bricks wide, with an opening about three feet across. Bricks are positioned at a slight angle and offset to create the curvature of the kiln. If the bricks seem unstable during stacking, then wait for them to dry before adding the next layer. Continue the curve until the bricks meet at the top of the kiln.
Reinforcing Doorways
- Screw steel strips to the doorways to provide support for the kiln. This will prevent the doorways from toppeling into the kiln. Use masonry screws and anchors to hold the steel in place. Allow the kiln to dry for about a week or two before placing wood inside to burn to create the heat necessary to fire pottery.

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