This casting was made using my homemade green sand. No need for very fine casting details it's just a sand box after all ;-)
This is my sketchup design:
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I made two patterns for each side of the flask, so the drag part is just a mirror image of the cope. The third pattern is my FlamingFurnace plaque name and flask size.
I made it optional to make the sand mould impression with or without it.
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In the next image you can a correction I made to the gating system for the sprue, riser. This small change from the gating system I have in the video will prevent porosity.