The practice of some shops embraces all three kinds of molding, but most foundries make only green-sand molds. These involve, however, more risk in making medium-sized and large castings. In many cases inexperienced men may be employed for making dry-sand molds, but it is seldom wise to trust other than skilled workmen with the construction of green-sand molds, especially in heavy work. Loam work varies greatly in the degree of skill required. Some classes of loam molds permit the employment of inexperienced workmen, while others demand extraordinary experience, skill, and good judgment in their production.
While the finished products of the three types of molding differ, as outlined, in shape, size, and use, the method is practically the same in all cases.