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«0:00 – Induction furnace preheating an empty clay graphite crucible before charging with brass. Materials only need to be conductive in the presence of an alternating magnetic field to induce a current, the part's own resistance then generates heat as the Eddy currents flow through the piece.» «0:15 - Charging with red brass ingots» «0:40 - Coming up to temperature pre-liquidous» «0:48 - Going liquid» «0:55 - Once the initial charge has melted and a "heel" has formed in the crucible another addition is made» «1:07 - Final additions and furnace coming up to power, the magnetic field produces a stirring action in the metal which can be seen by the metal appearing to "stand up" in the center of the coil» A thermocouple is a device formed by joining two dissimilar metals at a cold junction. When subject to a given temperature a corresponding voltage is produced which can be interpreted by a machine calibrated to the thermocouple type, this allows for accurate, fast temperature measurement in extremely harsh environments «1:32 - Small parts can be poured with a dip ladle to transfer metal to the prepared molds» «2:02 - While larger pieces are filled by using a crane to transfer the entire crucible after the inductive coil is lifted and swung away.» The pouring team in this video is a group of students being instructed on their first pour so the technique is a little sloppy but as a team notches more pours under their belt the entire process becomes very quick and efficient. "Cope float" is a result of the metallostatic pressure of the cast metal in conjunction with the surface area of the casting perpendicular to gravity producing a force that exceeds the downward force of gravity on the top part of the mold, known as the cope. This causes the cope to lift up and the two halves of the mold to separate resulting in what is known as a blow out, where the cast metal spilling out at the parting line of the mold. While sometimes castings can still be produced from a blow out, the pressure that drives metal into smaller details of a casting is lost and risers which serve as a reservoir of liquid metal supplied to the casting as it cools are lost resulting in warping and shrinkage, reducing the quality of the casting. Adhesives, clamps, and counterweights are all methods used to reduce the chance of a blow out occuring, as you can see at the end of the last video a blow out occured even though they used nearly 40 lbs of brass ingots in addition to the weight of the cope itself the high density of brass resulted in a pressure exceeding the force of gravity. Thanks a lot to Matt https://instagram.com/candelz95?igshid=4fp2z6geot4g for providing this video and explanation!
