Spachteln

Spachteln is a construction and craft technique that involves applying a filler material to a surface with a flat-edged tool, such as a putty knife, to smooth, fill, and level irregularities. In German-speaking contexts, the term refers to both the filler product and the action; in English, it is commonly called filling, spackling, or filling with putty.

Common fillers include spachtelmasse (joint compound), gypsum- or cement-based compounds, and polymer-based formulations such as acrylic or epoxy putties. For wood, wood filler or putty is used; for metal and automotive work, body filler and filler pastes are common. The primary tool is the spachtel or putty knife, available in various widths. Substrate-specific variants may require different hardness, drying times, and sanding characteristics.

Typical uses are repairing holes, gaps, and cracks in walls and ceilings, leveling joints in drywall, filling dents in wooden surfaces, and smoothing panels or metal surfaces before painting or finishing. It is also used in decorative plaster or craft projects.

Process steps generally include preparation (cleaning and drying the surface), applying thin coats of filler, smoothing with the knife to bring the area flush with the surrounding surface, allowing each coat to cure, sanding between coats, and applying a final coat. After curing, the surface is primed and painted or wallpapered as needed.

Key considerations are choosing a filler suitable for the substrate and environment (including moisture and temperature), avoiding excessive thickness in a single coat to prevent cracking and shrinkage, and ensuring ventilation and dust control during sanding. Spachteln provides a smooth base for finishes but does not repair structural defects.