I have a wood burning fireplace that was "renovated" by some previous owner in such a way that left a wooden stud exposed along the full width of the top of the firebox, just inside the front rim. I'd like to have that wooden piece covered up by firebricks so that it won't catch fire, but surface along the length of the wooden piece is covered by a steel plate, which means the firebrick would need to be attached to the steel plate somehow. My contractor used regular high-temperature mortar to cement the bricks to the steel plate, but they fell off within 3 days.
Is there a good mortar or other material that can be used to attach these bricks to the steel plate? I've considered Rutland 600°F RTV High Heat Silicone Sealant since I think it should be more forgiving with the bricks and metal expanding/contracting at different rates, but I'm not sure whether it has enough tensile strength to hold the weight of the bricks. I've also considered furnace cement which is supposed to be able to bond to both brick and metal, but it needs to be cured at 500 degrees and I'm not sure whether the very front of the fireplace could get that hot, even with a large fire going.
Is there a good mortar or other material that can be used to attach these bricks to the steel plate? I've considered Rutland 600°F RTV High Heat Silicone Sealant since I think it should be more forgiving with the bricks and metal expanding/contracting at different rates, but I'm not sure whether it has enough tensile strength to hold the weight of the bricks. I've also considered furnace cement which is supposed to be able to bond to both brick and metal, but it needs to be cured at 500 degrees and I'm not sure whether the very front of the fireplace could get that hot, even with a large fire going.
