Everything has been prepared for the white desk. The mold is a pretty standard construction. I had some leftover
MDF so I used that and spray painted to seal the wood. The desk has a thickened front edge to cover the in-place frame.
The desk will be white concrete with crushed glass in the surface. I saved some good blue and green bottles. First they were soaked in water to remove the labels, then crushed with a hammer to the appropriate size. Beer bottles can be problematic if not cleaned properly. The sugars in the beer tend to retard the concrete set. These were washed again after crushing.
How do you make white concrete,
mmm use white cement. This is a little harder to track down for the average person since Home Depot doesn't carry it. Masons and stucco guys use white cement or call your local decorative supplier. This cement and sand was donated by Mike Murry at
Decorative Concrete Supply. The only real difference between white and regular Portland cement is they leave out the
tetracalcium aluminoferrite. It is a small part of regular cement that doesn't really contribute to strength.
Another concern for making white concrete is the aggregate. Regular sand tends to make the white cement concrete a
tanish color. You can buy pure silica sand (ash tray sand) at local suppliers. Since this is a small desk, shrinkage isn't really a concern so a mortar mix is appropriate.
The mix will be a standard mortar mix; 2.5:1 sand to cement, water-to-cement 0.40, 10% metakaolin clay, high range water reducer, viscosity modifier, latex, polypropylene fibers, cellulose fibers, and de-air entraining agent. The total batch will be 1.0 cf.
