Preparation of ground sections using UV-curable acrylic adhesives

Abstract

Study of ground sections is the most used and, in some respects, still irreplaceable method for examination the microstructure of paleontological and many other hard and friable objects. At the same time, paleontological samples are relatively difficult for preparations of high-quality thin sections. Many techniques and means, particularly embedding media, have been proposed, but they are often hardly accessible, imperfect or insufficiently studied. A promising and easily accessible non-specialized medium, UV-curable acrylic adhesive (glue for glass) was tested for embedding and mounting of objects with diverse mechanical and optical properties. It shows notably good results, in particular durability, reliable adhesion, ease of use and lack of significant birefringence, which makes it especially valuable for polarized light microscopy. Properties of such adhesives are reviewed and compared with properties of epoxy resins and a number of other media. Disadvantages of the adhesives and ways to deal with them are also elucidated. In addition, broadly accessible tools and methods of sawing, embedding, grinding, mounting and other stages of the work are discussed. Efficiency of a number of grinding agents is measured. On the basis of all these results, a technique of making ground sections using easily accessible means was developed and described step by step. The technique was designed for fossil bones, but is applicable to diverse dry samples, including paleontological, neontological and geological ones.