Solid wood sanding

Refers to the calibrating and smoothing of workpieces of solid wood, using abrasives.

Problem of solid wood sanding

Unlike wood-based panels with a homogeneous structure of chips or fibers, solid wood consists of different zones with different properties, which significantly affect the sanding result.

Early wood zones Soft wood zones, which are formed in the living tree during the spring months and which especially serve the growth in thickness and the water transport in the living trunk. These wood zones can be identified by their lighter color in most tree species.
Late wood zones Hard wood zones, which are formed in the living tree during the summer months and which especially serve to strengthen the trunk. These wood zones can be identified by their darker color in most tree species.
Branches They run at an angle to the wood fibers of the trunk and form hard zones.
Resin galls These can be formed in the living trunk of softwood tree species because of strong wood bending during storms when wood fibers are separated from each other because of the different tensile. The cavities that are formed are filled with resin by the tree.
Heartwood The tree fills the dead wood zones facing the trunk's center with different substances for wood bonding and for thwarting fungi and wood-eating insects. These zones are harder and darker in heartwood forming tree species than the lighter wood in the trunk center of non-heartwood forming tree species.
Sapwood Wood zone on the outside of the heartwood which serves the water transport in the trunk and often is lighter and softer than the heartwood.

When sanding the differently hard, closely located wood zones with a soft sanding pad or soft rubber roller, the softer wood zones are ground out deeper than the harder zones. This process, called washing out, leads to a rustic look, which is preferred by some of the trends in interior design. Sanding with a steel roller, hard rubber roller or hard sanding pad prevents the wash-out effect.

Particularly resinous wood zones lead to a gluing of the pores of the abrasive and thus, to a deterioration of the quality.

Applications

Solid wood in its different forms can be sanded with different machines.

Wide belt sanders

Sanding of panels made of solid wood (e.g. chipboard, fillings):

  • Planing (very rare, only industry)
  • 1 to 2 calibrating rollers of steel or hard rubber (75° Shore and more)
  • 1 to 2 sanding pads, hard felt (optional air cushion)
  • Brush and/or structuring roller (structuring requires more driving power, at least 4 kW)

Sanding of frames, door and window frames

Images

Jahrringzonen und Ast
HÖCHSMANN, 2011