Halflining

Halflining is a term used in multiple contexts to describe the partial application of a lining or protective layer to a component or structure. It typically denotes that only a defined half or portion of a surface receives the lining, while the complementary half remains uncoated. The concept is most often encountered in materials engineering, piping inspection, and related fields, though usage varies by discipline. Because the term has no single, universally accepted definition, writers may also spell it half-lining or partial lining.

In practice, halflining begins with surface preparation of the target half, selection of an appropriate lining material (such as epoxy, polymeric coatings, or ceramic linings), and masking of the non-target half to prevent coating. The material is then applied to the selected half by brushing, spraying, or dipping, and cured under specified conditions. Quality control focuses on the seam at the boundary between lined and unlined regions, as well as the absence of pinholes and voids at the coated surface.

Applications include comparative testing of corrosion resistance, wear resistance, or thermal insulation, as well as staged rehabilitation plans where full lining is not immediately feasible. Halflining can also serve design purposes in which a dual-surface effect is required. Potential drawbacks include seam delamination, differential thermal expansion, and maintenance complexities arising from the boundary.

In fiction and speculative design, halflining can be used as a plot device or worldbuilding element to describe a partially protected or partitioned environment. See also: partial coating, half-lining.