airmodel has a very good pouring technique, which can be difficult to do.
If one initially pours too fast, then you may not be centered on the sprue, or the pour stream will be too wide, and metal will go everywhere.
If one initially pours too slow, then you get air aspirated down the spure, and air flowing into the mold cavity.
The trick is to start pouring exactly in the correct spot, and then exponentially increase the flow rate quickly, to fill the sprue and keep it full.
If you miscalculate on the ramp-up speed, again you generally spill metal everywhere.
If you hesitate and the flow stops for even a fraction of a second, you have an interrupted pour, which can cause a lot of problems in a casting.
It is very much an art to pouring technique, and one can be a bit nervous due to the radiated heat, and the images of a spill vaporizing part(s) of your body.
Thoughts linger in the back of one's mind about whether there is some residual moisture in the mold which will cause it to explode, which is always a big surprise.
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