Mounting of specimens is usually necessary to allow them to be handled easily. It also minimizes the amount of damage likely to be caused to the specimen itself.

The mounting material used should not influence the specimen as a result of chemical reaction or mechanical stresses. It should adhere well to the specimen, and if the specimen is to be electropolished later in the preparation then the mounting material should also be electrically conducting.

Specimens can be hot mounted (about 150 °C) using a mounting press either in a thermosetting plastic, e.g. phenolic resin, or a thermosoftening plastic e.g. acrylic resin. Iqualitrol provides manual hot mounting press XPress-385, automatic mounting press iPress-889 and double moulds mounting press iPress-887 / iPress-886 which can make 2 specimens simultaneously.

If hot mounting will alter the structure of the specimen a cold-setting resin can be used, e.g. epoxy, acrylic or polyester resin. Porous materials must be impregnated by resin before mounting or polishing, to prevent grit, polishing media or etchant being trapped in the pores, and to preserve the open structure of the material.

A mounted specimen usually has a thickness of about half its diameter, to prevent rocking during grinding and polishing. The edges of the mounted specimen should also be rounded to minimize the damage to grinding and polishing discs.

A mounted specimen (shows typical dimensions)