These molds were made to create uniform concrete specimens for ASTM scaling experiments. Angle iron for the height was used on the ends. Square plates that were drilled and tapped were welded to the ends of the angle iron. A piece of rebar was welded across to make a handle to make it easier to pick up and move them. Everything was assembled using 1/4-20 bolts.
Metal Concrete Mold for Scaling Specimens