Restoration and painting of historical metal parts using linseed oil paints

Unlike modern synthetic coatings, which often form an impermeable film and can promote hidden corrosion, natural linseed oil paints provide long-lasting protection that is easy to maintain and restore.

1. Surface Cleaning and Corrosion Layer Removal

In the restoration of historical metal parts, the primary task is the gentle removal of the existing coating layer without damaging the underlying metal structure. One of the most effective and gentle methods is thermal treatment in a linseed oil soap solution.

  • Method: Parts are placed in a solution consisting of 50% Allbäck linseed oil soap and 50% water.
  • Process: The parts are "boiled" in the solution for several hours, then left to cool in the solution for several hours. The alkaline environment softens old paint and corrosion layers.
  • Mechanical Cleaning: After boiling, the surface is treated with a metal brush, rinsed with water, and immediately dried to prevent immediate surface oxidation.

2. Surface Preparation and Degreasing

Before starting painting, the surface must be dry and free of grease. For metal parts, the correct choice of solvent is crucial.

  • Degreasing: The surface should be treated with technical alcohol. Unlike white spirit or other petroleum products, alcohol completely evaporates without leaving oily residues that could impair paint adhesion.
  • Environmental Conditions: During painting, the surface and air temperature should be at least +14 °C. The relative humidity should be below 50%, and there should be no signs of condensation on the metal.

3. Painting Process and Technical Parameters

Allbäck linseed oil paints contain no solvents. This means the paint does not evaporate but hardens (oxidizes) throughout the applied layer thickness.

  • Application: The paint should be applied in a very thin, even layer. It is recommended to paint at least twice and use brushes suitable for painting with linseed oil paints.
  • Additives: The paint must be supplemented with 10–20% natural mineral additive zinc oxide (20% for light shades, 10% for dark shades). This ensures layer hardness and increases resistance to mold and biological degradation.
  • Oxidation Phase: Linseed oil paint dries in approximately 24 hours at room temperature. Lower temperatures and increased humidity can significantly extend drying time.

4. Treatment of Heat-Resistant Cast Iron Parts

For the treatment of stove and fireplace parts, a specialized composition — Stove Blacking, consisting of heated linseed oil and graphite powder, is used.

  • Application: The composition is applied with a brush or sponge to a previously cleaned surface.
  • Final Phase: Excess material is carefully wiped off with a soft cloth. After initial drying (24–48 h), the surface is heated, which helps the composition fully set into the surface.

Summary

Painting metal parts with linseed oil paint provides not only an authentic and historical visual result but also functional protection that is easy to maintain and restore. Unlike synthetic paints, linseed oil paint does not crack or peel over time but naturally wears (oxidizes) — becoming matte, which allows for paint restoration simply by treating it with heated linseed oil or wax.

 

Back to blog