Spiral sprue loop

A method for fabricating a mold, comprising the steps of:

• mounting a sprue loop to a sprue base, the loop including a loop element and spiral arms attached to the loop element and extending inwardly of the loop element and out of the plane of the loop element and terminating in a base element;
• spruing at least one sprue pin and wax pattern attached thereto to the loop element at an angle to the loop element which is similar to that angle at which the spiral arms are attached to the loop element;
• and,
• forming an investment mold about the sprue loop to define a sprue channel shaped according to the definition provided by the sprue loop and the sprue pin.

In an apparatus useful in the fabrication of a mold having a sprue channel, the sprue channel being at least partially formed by at least one sprue pin and wax pattern luted to the sprue pin, the apparatus being mountable to a sprue base, the improvement comprising:

• a base element mountable to the sprue base;
• loop means for mounting at least one sprue pin and wax pattern luted together;
• and,
• spiral arm means mounted to the loop means and extending inwardly of the loop means and out of plane of the loop means for forming portions of the sprue channel on removal from the mold produced through use of the apparatus, which portions of the sprue channel minimize turbulence of casting material introduced into the mold, the portions of the sprue channel formed by the arm means further channeling the casting material to the loop means, the arm means terminating in connection to the base element, the base element, the arm means, the loop means and the sprue pin and wax pattern luted together forming in combination said sprue channel in the mold on removal thereof from the mold produced through use of the apparatus.