One of my casting students attempted to cast with Rio Grande’s
manganese bronze alloy. Standard lost wax casting, investment mold,
vacuum, oxy-acetylene flame. New, freshly seasoned crucible (seasoned
with borax). Not only did the alloy not melt completely, but it
sputtered and spattered onto the concrete floor, and actually ignited
twice, with a blue-green flame that went out when we moved the torch
away. I researched the MSDS, and it says that the alloy may “react
violently with oxidizing agents”. Rio’s description says that it is
suitable for centrifugal casting into refractory molds, but does not
mention anything about possible reactions with the flame, even though
the alloy is listed with all its other casting alloys.
My initial suspicion is that the manganese is reacting in some way
with the oxygen in the flame. I am wondering if an electric melt
would be more suitable, and if it can even be used with
vacuum-casting into an investment mold.
Any input would be greatly appreciated. We poured the semi-melted
alloy into the water quench bucket, and got some beautifully colored
Thank you in advance for your inputs.