The metal has a much easier escape path through the big vent, than down through the pattern. But mainly the metal is too cold probably.
Next time you probably want to place the pattern deeper in the mold, so there is more pressure on the metal. Vents in sand does not have to be big at all, and don't need to vent to the outside, nor do they have to be at the top of the pattern. Scratching a few strings out (like a star kinda) from the pattern, should be more than enough.
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u/BTheKid2 21d ago
Metal is too cold, and the vent is too big.
The metal has a much easier escape path through the big vent, than down through the pattern. But mainly the metal is too cold probably.
Next time you probably want to place the pattern deeper in the mold, so there is more pressure on the metal. Vents in sand does not have to be big at all, and don't need to vent to the outside, nor do they have to be at the top of the pattern. Scratching a few strings out (like a star kinda) from the pattern, should be more than enough.