How to make custom concrete brick

masonry

I would like to make a custom brick for a decorative purpose. It will be painted so the material is not important, meaning it doesn't have to be a clay brick, could be concrete like cinder blocks. I can make my mold very easily but I am unsure about the mix to put in. These instructions are for clay bricks and require a long time of curing them in the sun, and I have neither time nor sun at my disposal.

If I were to pour my brick with some cement-based material (like concrete), what ingredients and ratios should I mix and how is that the mix (if any) different from a regular concrete mix? Also, is there a way to make a clay brick faster than the instructions submitted, since I need only one I could cook it in my kitchen oven for example? While concrete is acceptable, clay would be slightly preferred if not much harder to work with.

Best Answer

If purely decorative, plaster-of-Paris (aka gypsum paster) sets quickly, takes detail from molds well, and paints well.

The brick link you provided is for "sun-dried mud brick" or "adobe" (more or less) - I suspect plaster would be at least as strong as that. Normal clay brick is kiln fired (your home oven won't do it, but odds are there's a potter or 3 in your town with kilns.) Any clay brick requires some drying time (or it will crack if dried too swiftly) unless it is pressed (at very high pressure) from dry powdered clay.

Brickmaking link