Rio Grande Cast-In-One™ Penta-Form™ Sprue Button

The heart of the Rio Grande Cast-In-One™ design, this wax Penta-form™ structure not only acts as the sprue button in the treeing and casting processes for this machine, but also makes it possible to cast without a crucible. The Penta-form is a small, flat-topped, five-legged structure that seats into five tiny corresponding holes designed into the apex of the high "button" on the rubber base; these holes will ultimately be the pathway for the molten metal to enter the pattern molds.

• In building, then investing, your wax tree and its patterns, do not allow wax to get into the 1/8" of space between the Penta-form and the rubber base below it; any wax here will prevent proper investing and impede (or prevent) the metal flow during the cast.
• During the burnout, the tree, models and Penta-form™ structure melt and are evacuated from the investment, leaving behind five tiny holes between the empty "button" reservoir and the pattern molds.
• When the melt temperature is reached, pressure and vacuum are simultaneously applied, effectively drawing the molten metal through the five holes and into the patterns below.