Petrobond only requires one entry hole, i use a pneumatic tamper to pack the sand in around the pattern. Sand packs hard as a brick.
I use a tapered coffee table leg which is positioned before tamping, use a knife to cut in a runner, spoon to scoop out a funnel at the top of the sprue hole, makes pouring the molten metal easier.
Metal being poured into the cope enters a pocket carved into the sand which resides nearby the mold cavity, a runner is cut from this pocket to allow metal to enter the mold cavity.
The pocket serves two purposes, feeds metal into the mold cavity then feeds shrinkage, any junk ( dross ) floats to the top on this pocket so only clean metal reaches the mold cavity.
Use a plastic straw to gently blow out any loose sand that enters the mold cavity.
On a side note we would not be good neighbours, you make much too much noise.
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