What is Roses Metal?
Roses metal, also known as Rose’s Metal, is a fusible alloy. It consists of a combination of bismuth, lead and tin. A fusible alloy is a metal that has a very low melting point and its uses include anchoring, mould applications and fusible links.
Valentin Rose the Elder, a German pharmacist and chemist, was the first person to discover this metal that was then named “Rose Metal” after himself.
Rose Metal Properties
One of its properties is that it has a very low melting point and even though fusible alloys are usually eutectic (the property of being solidified at a lower temperature than other compositions), Roses Metal alloy is not. Another property that is relevant is that it contracts slightly when cooling from 80°C to 55°C, then expands again between 55° to 35°C.
What is Roses metal used for?
It is mainly used as a solder. Alloys such as Roses metal, that have low melting points, are used by makers in the process of soldering so that they can join the different pieces by melting. As it melts at a very low temperature, the work pieces remain unaffected when joined by this metal. Roses Metal is also used to secure cast iron railings and balusters to stone bases and steps.
In industry, Roses metal is applied as a malleable filling to prevent tubes and pipes from crimping when bent. In this process, the tube to be bent is first filled with melted Rose metal. Next, the metal must be solidified, but remains malleable. This allows the tube or pipe to be bent and reworked without the crimping. When the tube attains the desired shape, the Rose metal is re-melted and poured out of the tube.
In a constant temperature bath, Roses metal is used as a heat transfer medium. It is usually not used for the process at lower temperatures. It is employed only in hot bath with temperatures above 220°C.
Rose metal can also be used as a low temperature casting metal for artists as well as industry. It is ideal for pouring silicone, plaster and rubber moulds as well as 3D printed plastic.
Finally, it is quite popular as a valve element in automatic fire sprinklers. The valve, having a low melting point, melts in fire and provides water to stop the fire from spreading.