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| January 2009 | Courtesy of BEGO USA Good Vibrations During the C&B investing process, many technicians will often place their filled mixing bowl on the vibrator while cleaning the investment off the paddle, believing it will help get the trapped air bubbles out of the investment. In reality, this process creates another problem. The large, heavier particles in the investment move to the bottom of the mixture and the smaller, lighter particles move to the top of the mixture in the bowl. A good vacuum mixing machine should eliminate the air bubbles from your mixed investment without the need for vibration. A similar effect also happens when there is continued vibration when filling the casting ring with investment. As the separation occurs, the larger particles move away from your wax up and form a honey comb structure behind the thinner layer of smaller particles. During the casting process, the high speed of the molten alloy entering into the mould can break through the thin layer of smaller particles which are not 100% supported due to the honey comb effect. This breakdown may cause rough surfaces on your castings. To help ensure smoother castings and save on finishing time, pour your investment right after the vacuum mixing has stopped and only use vibration when the investment reaches the wax up and flows past the copings. |
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 For more information, call your local dealer or BEGO USA, 1.800.342.2346 | |
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