Lost foam casting: carve it in styrofoam, bury it in sand, pour

Lost foam skips pattern draft, parting lines and cope-and-drag entirely. Cut the shape from white bead foam (not pink/blue XPS, it gasses more), glue on a foam sprue, coat it in a thin drywall-mud wash and let it dry, bury it in dry loose sand in a bucket, vibrate the bucket so the sand packs, and pour fast. The foam vaporizes and the metal takes its place.

Surface finish shows every bead of the foam, so sand the pattern smooth and use two coats of wash. Great for one-offs like brackets and handles. Pour outside; the smoke is unpleasant.