I have a bunch of manufactured sand/stone dust left over from a setting a patio. Any reason this should not be used under the fire bricks in the oven? The material is a mix of fines, small, medium, and coarse sand.
Hello, Ida24, and welcome to the BrickWood forum.
The sand under the hearth firebrick is used for the same purpose. As long as it does not have polymers or other stabilizing chemicals in it (i.e. it’s just sand), it would fit the bill.