This product is easy to use and easy to color. Take care not to overfill the mold. That makes a convex backing that is difficult to attach to your layout. I use joint compound to attach and join the mold pieces because it dries harder. That allows you to scrape away unwanted slag. To color, use thin acrylic paints. First, spot the pieces with 3 different color paints such as red, yellow and blue. Then use an even thinner gray paint to brush over the entire area mixing the paints. This product works best with a fine plaster such as Woodland Scenics' Hydrocal. Other cheaper plasters are heavier and leave bubbles in the mold that make the pieces unusable.