Dry ice is the solid form of carbon dioxide (CO2) occurring at a temperature of -78.5 °C. Mechanical engineers and artisans commonly use dry ice in a process referred to as shrink fitting (also known as ze fitting).
Bearings are an integral part of a machine’s moving components and reduce the amount of friction on rotating parts. Bearing failure is common in older machines and vehicles, particularly those in high-wear conditions such as a mining or chemical environment.
Shrink fitting is commonly used in engineering to fit together bearings, collars, shafts, and other components which require an interference fit. The component to be “fitted in” to the other part is packed in dry ice causing it to contract. While still cold, it is assembled with its mating part and allowed to return to ambient temperature. In doing so, the cold part returns to its original size and creates the tight interference fit required. This process is quick, simple to use, and causes no changes in the physical properties of the components, unlike heating the respective components which can change the hardness or toughness of the materials.
Use an insulated cooler or polystyrene container. We can supply you with the perfect size polystyrene container, or you can wrap the dry ice in paper or a blanket to extend the life even further if necessary.
If stored correctly, it will last five to ten days.
+27 (0)10 040 3201