Q: What is Bismuth?
A: Bismuth is an element found in nature. It is heavy with a course crystalline structure that expands 3.3% by volume upon solidification.
Q: Do all of the alloys that contain Bismuth expand upon solidification?
A: No. As a general rule, the alloys that contain more than 50% Bismuth will expand upon solidicifation. The alloys that contain less than 50% tend to shrink during solidification.
Q: Is Bismuth safe to handle?
A: Yes. Bismuth is non-toxic.
Q: What other elements are in the different alloys?
A: The alloys all differ in the combination of elements. Not all of the alloys contain all of these elements but the possible elements are: Tin, Lead, Indium, Cadmium, Zinc, Antimony and Silver.
Q: Are there any "Lead-free" alloys?
A: Yes. The 3 most popular alloys that do not contain Lead or Cadmium are: Cerrotru, Cerrocast and Cerrolow 174.
Q: Which of the alloys remain the same size that can be used for delicate internal measurment and proof casting?
A: The 3 alloys that are used for such purpose are: Cerrolow 117 @ .0000" in 30 minutes after casting; Cerrolow 136 and Cerrosafe @ .0000" in one hour after casting.
Q: What kind of material can molds be made from?
A: Most anything will work for mold material. This biggest factor is the melting temperature of the alloy being used. Metal molds and silicon molds can be used for high temperature alloys while most anything can be used for low temperature molds ranging from cardboard, wood, plaster, styrofoam and plastic to standard metal molds.
Q: Do I need special equipment for melting alloys?
A: The lower temperature alloys have a melting temperature lower than boiling water (212ºF). For this, a simple double boiler will do. For alloys with a higher melting temperature, most any external heat source, that can be controlled, under a metal container can be used but it is essential to use a thermometer with this method. There are automatic pots available.
Q: How can I determine the correct temperature to pour (cast) an alloy into a mold?
A: Pouring temperatures should be kept as near to the melting temperature as possible yet it must be high enough to prevent cold sets or steps. As as general rule, pouring at 25ºF above the melting temperature will be adequate.
FREQUENTLY ASKED QUESTIONS
Frequently Asked Questions