ART 35  ~  SCULPTURE: CASTING

Handout #5: GATING CHECKLIST Name_________

Preparing the wax pattern:

1. The wax pattern must be complete and manifest the artist's vision and intention. (While the transformation into bronze is exciting and beautiful, it will not magically improve inherent flaws!) No pattern is complete until it bears the artist's signature and the year made. Copyright and edition #'s are optional.
2. The wax pattern must be sturdy and hold together well. The thickness must be as consistent as possible: preferably about 3/16 inch.
3. The surface should be clean and any small air bubbles, deep crevices or other flaws must be sealed or repaired. Shellac (thinned with alcohol) may be applied.
4. Determine the number of sections large pieces must be cut into; make cuts. (This may provide another opportunity to inspect and fix the thickness of the pattern.)
5. Determine the location of any 'windows' needed to support the core or to allow air to flow out through the pattern as investment flows in; make cuts.
6. Shave a bevel along the perimeter of any wax sections to be welded later.

Gating the wax pattern:

1. Determine whether the piece will be poured 'directly' or 'indirectly': most pieces will be gated indirectly, although simple or solid pieces might be gated directly.
2. Establish the best 'attitude' for the piece to be in during the pouring process. This includes insuring that the main core is facing up so that gasses can escape.
3. Determine where the cup and main runner will be in relation to the pattern.
4. Design and build a gating system that takes these issues into account:
   1. Space gates 4-5 inches apart, mostly on the bottom half; avoid surface details.
   2. Always point gates uphill from main runner, so that the piece fills with bronze through these gates from the bottom up, allowing the air to rush out vents.
   3. Keep the gates about 1-2 inches away from pattern. Provide room to cut later.
   4. Runners and gates generally use square wax, vents and risers use round.
   5. Be Patient! Support the piece well and never disturb fresh welds!
5. Locate any high points and attach vents, jumpers, or 'blind' vents to these spots. Vents should come straight up, away from the top of the cup. Attach windows.
6. Place core pins (made of bronze rod) as necessary, typically three, in lower half.
7. Place bronze pins on a strand of wax to use as a 'core vent' in hollow pieces.
8. A 'dirt trap' may be placed on the extreme bottom point(s) of the pattern.
9. Inspect and gently test all welds, clean off any drips and double-check this list.
10. Weigh your gated piece. Multiply weight by 10#, add 5# for cup. Record weight.
11. For "Board Pour": firmly weld cup and risers to a board with 4" extra on all sides.