Kiln Repair Cement
Handle your kiln carefully to avoid damaging the firebricks. But when a firebrick edge breaks off, don’t worry. The damage is usually slight and does not affect the firings. The damage described above is minor. You can repair broken firebrick pieces yourself with kiln cement. Before applying the cement, vacuum the firebrick surfaces.
Our Kiln Repair Kit for firebrick kilns includes a 1 lb. bag of Powdered Kiln Repair Cement and 1-pint bottle of Liquid Kiln Repair Cement.
HOW TO MIX POWDERED KILN CEMENT
Kiln cement is used to glue firebricks together. You can see the cement seams in a firebrick lid or bottom. When applied properly, the cement becomes stronger than the firebricks themselves.
There is an art to using kiln cement. The first step is to mix it properly. It comes in liquid and powder form; Many prefer the powder, because they can mix it to the exact consistency that they want. Our kit includes both as we think its always nice to have options!
Paragon’s founder, the late Frances Darby, used to say, “Mix the cement to the consistency of peanut butter, and you love peanut butter.” The exact ratio of powder to water may vary depending on the brand of cement; Paragon’s “Kiln Coating and Repair Cement” should be mixed 4 parts powder to 1 part water by volume. Measure the powder and water with a small scoop such as the type that comes with protein powder. Stir the cement thoroughly.
Note: Do not breathe firebrick dust or kiln cement.
HOW TO APPLY KILN CEMENT TO FIREBRICKS
As you will find, once the cement is applied to a firebrick piece, the cement quickly loses its peanut butter consistency, because moisture from the cement absorbs into the firebrick. This is why the cement must be applied quickly to the firebrick piece.
If possible, do not apply the cement to the firebrick with a putty knife or other tool. Instead, dip the firebrick piece into the cement. This is much faster. Apply the cement to only one surface. Then work rapidly. (You may find it helpful to moisten the firebrick pieces with water before you apply the cement.)
As you press the firebrick piece against the broken edge you are repairing, wiggle or twist the piece into place. This squeezes out the excess cement from the seam, which should be as thin as possible. Twisting the firebrick piece into position also presses the cement into the firebrick pores. This is necessary for a good bond.
Hold the pieces together for one minute. Then wipe off the excess cement being careful not to disturb the firebricks you have just cemented together.