Following cutting or sectioning the specimen is typically mounted. Mounting provides the following advantages:
• Convenient means to hold the specimen
• Provides a standard means to mount multiple specimens
• Protect edges
• Provide proper specimen orientation
• Provides a means to label and store the specimens
Hot mounting is quick and easy to produce, requiring several minutes at the appropriate mounting temperature. Most of the time required in compression hot mounting occurs in the heating and cooling stages. Hot mounting resins include:
• Phenolic Resins
• Acrylic Resins
• Epoxy Resins (glass filled)
• Diallyl Phthalate Resins
• Conductive Resins
The most important properties of a hot mounting resin are; Hardness, Shrinkage and Viscosity.
The Hardness of the compound should match the hardness of the specimen in order to avoid uneven abrasion during grinding. If the shrinkage during curing is large, a gap between the specimen and the mount will occur and edge will not be adequately protected. Viscosity is important to reach to all areas.
Cold mounting is preferred for samples which are sensitive to damage from heat and pressure (like coatings, PCB, etc.) Cold mounting resins are cross-linked polymers that are easy to use and require mixing of powder and liquid. The mix is then poured into a mould and allowed to set.