What is Hot Mounting? – Working with Resin

Resin is a versatile substance that can be used in castings, arts and crafts, flooring, and making plastics. The way that resin is used in mounting can depend on whether it is thermosetting or thermoplastic; thermosetting is an irreversible process as the resin cures at an elevated temperature.

Hot mounting is an ideal, short process when using resin to produce an item of uniform size and shape. Hot mounting occurs in a mounting press, wherein a sample is placed together with the appropriate mounting resin and a high temperature and pressure combination allows for the sample to be embedded. Thermoplastic resins harden with or without pressure, so the high pressure is unnecessary in this case.

To ensure uniform mounts the pressure must remain constant at the correct level. With thermosetting resins, once the mount is cured, the specimen can only be removed if the mount is destroyed. When using thermoplastic resins, the resin is heated and then pressed. The choice of resin is important to satisfy the mounting requirements.

Metallography involves the study of the microstructure of metallic alloys, such as copper and aluminium. The analysis of microstructures allows us to determine whether a material has been processed correctly, i.e., whether a material is stable enough. The samples used should be prepared so that they can be examined microscopically, and this process can involve hot mounting resins. For example, epoxy resin can be used since it allows for sample examination at high magnifications and results in no gap between the resin and sample.

Backfilling can also be used to combine different resins. A high-quality resin, such as epoxy resin, can be applied to the bottom of the sample for ideal preparation results and then a lower cost resin, such as phenolic resin, can be added to reduce the cost of the complete mount.