Wood filler for stain grade wood surfaces is used to fill nail holes, nicks, gouges, and scratches. Some types of fillers are intended to be applied to raw wood before staining and clear finishing. Other types of fillers are meant to be used after clear coats have been applied.
Solvent Base Wood Filler
Solvent (acetone) base filler is a fast drying wood paste designed for filling nail holes, cracks, and gouges in raw wood before wood stain or clear coats are applied. Because this type of filler is made from actual wood fibers, it has the ability to absorb wood stain. When applying this type of product, it should be slightly overfilled. Once the filler has completely dried, it can easily be sanded flush with 150-grit sandpaper, to match the profile of the surrounding wood surface. This product is available in a variety of colors designed to replicate different wood species. It can also be tinted with colorants. Choosing pre-tinted filler that matches the original wood is an advantage when applying wood stain.
Water Base Wood Filler
Water base wood filler, much like the solvent base product is used for filling nail holes, cracks, and gouges in raw wood before wood stain or clear coats are applied. For wood stain applications, be sure to choose filler that will accept wood stain. Water base wood fillers have come into their own in recent years, but they do have a tendency to shrink more and take longer to dry than their solvent base counterparts. The slower drying time does improve the workability of the filler, especially for filling open wood grain. Water base filler is available in a variety of colors to match several popular wood colors.
Colored Wood Putty
Colored wood putty is oil base putty that works well for filling nail holes, cracks, and seams on pre-finished wood where wood stain and/or clear coats have already been applied. Once the filling has been completed, additional clear coats may be applied to achieve a uniform sheen at the fill spots. Because colored putty does not need to be sanded, it should be put on flush with the surrounding surface profile of the wood. This type of filler is available in a variety of colors that match up well to popular wood stains. These colors can also be intermixed to create new custom colors. As with most oil base putties, colored wood putty tends to be somewhat sticky. Whiting can be added to create a more workable consistency.
Wax Fill Sticks
Wax fill sticks are used to fill small to medium sized holes on finished woodwork. They are available in a variety of colors to closely match most wood finish colors. Choose a slightly darker color if there is not a stick with an exact match. The wax is hard at room temperature. Warm a small amount of wax shavings with your hand so the wax can become more pliable. Apply the softened wax into the holes and allow it to harden. Remove the excess wax by buffing the surface with a soft, lint free cotton cloth.
Touch-up pens are used to add color to small blemishes on wood. They work well to blend in the color on small scratches, glue spots, and discolored filler spots. There are several varieties of touch-up pens used in the wood finishing industry. A popular type is the ethanol based pens. They are available in a wide selection of colors.