Here are some common mistakes to avoid when using fire brick mortar:
Using the wrong type of mortar.
Make sure you use a mortar specifically designed for fire brick applications. Regular mortars will not withstand the high temperatures and can fail prematurely.
Adding too much water.
Do not add too much water to the mortar. This can weaken the mortar and cause it to crack under heat. Add water slowly and mix thoroughly until you reach the proper consistency.
Not pre-wetting the fire bricks.
The fire bricks should be sprayed with water before applying the mortar. This helps the mortar bond better to the bricks.
Applying mortar unevenly.
The mortar should be applied evenly and smoothly on all sides of the fire brick. Uneven application can lead to cracking.
Not properly curing the mortar.
The mortar needs time to fully cure before exposing it to high heat. Follow the recommended curing time on the mortar product before starting up the fire brick installation.
Not installing expansion joints.
Expansion joints should be installed every 20-30 feet to allow for thermal expansion. Failure to do so can cause significant damage over time.
Heating up too quickly.
Once the fire brick installation is complete, the temperature should be increased slowly over time. Rapid heating can cause the mortar to fail before fully curing.
Overlaying mortar onto the face of fire bricks.
Mortar should only be applied between fire bricks, not overlaying the exposed brick faces. Mortar applied to brick faces can spall off over time due to thermal cycling.
Not cleaning fire bricks before installation.
Fire bricks should be clean and free of dirt or debris before installing and applying mortar. Anything attached to the brick can prevent proper adhesion.