Pore Filling — Lutherie Encyclopedia

Pore FillingType: techniqueFilling the open pores of coarse-grained woods like rosewood and mahogany to create a smooth, level surface for finishing.## Overview Pore filling is a preparatory step performed on open-grained woods before applying a finish. Woods like rosewood, mahogany, ash, and walnut have large, visible pores that, if left unfilled, create a textured surface that shows through the finish as tiny pits or valleys. Pore filling creates a smooth, level foundation that allows the final finish to achieve a mirror-like gloss with fewer coats. ## Process There are several pore-filling methods, each with advantages and drawbacks. **Commercial paste fillers**: These are the most common choice. A paste filler (oil-based or water-based) is mixed to a thick but spreadable consistency and tinted to match the wood color. It is applied liberally across the grain using a plastic spreader or stiff brush, forcing it into the pores. After setting briefly (10-20 minutes), the excess is wiped off across the grain with burlap or a stiff cloth. The filled surface is left to dry completely (24-48 hours for oil-based), then lightly sanded. **Pumice and shellac**: Traditional for French polishing, this method uses fine pumice powder dusted onto the surface and worked into the pores with a shellac-charged polishing pad. The friction generates a slurry that fills the pores with a mixture of pumice, shellac, and wood dust. **Epoxy filling**: Thin epoxy is applied to the surface, allowed to partially cure, and scraped flush. This produces an extremely durable fill but is difficult to color-match and may affect the finish adhesion. **Su…