5.6.1 Sanding of wood

Objective:

Sanding is a mechanical surface treatment method for removing the uppermost layers of the substrate and exposing the actual base substrate.

Suitability:

Sanding is suitable for wood.

Procedure:

  • It is not necessary to clean and degrease the surface
  • Manually with an abrasive block or using sanding machines
  • Grain size from K 120 to 180 is best for adhesive bonding applications
  • After sanding remove all dust, etc. from the surface

Points to heed:

  • Regularly change the abrasive paper
  • Ensure the surface has a uniform finish
  • Remove all residues and dust from the surface after sanding
  • When sanding using machines, the wood can become too hot and can burn
  • Risk of residues of the abrasive material in the substrate
  • Abrasive materials can sometimes introduce iron ions into the wood. When bonding with dispersion adhesives this can lead to a blue coloration (when bonding oak, chestnut and walnut (tannic acid containing woods)).
  • For extract-rich woods, sanding causes the extracts (oils, resins, minerals) to accumulate on the wood surface. It is possible that this can adversely affect the bonding properties.
  • The time between sanding and bonding should be short. Long interim storage can result in extracts migrating to the surface, negatively affecting the subsequent bonding process.