The base of these fillers is some finely ground substance which, when mixed with oil and dryer and thinned with turpentine or benzine and applied to wood, will fill the pores or interstices so thoroughly as to render the surfaces thus treated impervious or non-absorbent. Silex, talc, terra alba, whiting, china clay and barytes are largely used for this purpose. The more transparent and white the base is, the more satisfactory its use, as the object is to preserve the natural color of the wood, or, if a stain is used, the filler must not dull or injure the transparency of the color combined with it.

Starch, glue and dextrine may also be used, but are more perishable and, therefore, not so good.

A good paste filler is made as follows: Grind dry silex to a paste in a mixture of 4 parts raw linseed oil and 1 part good Japan dryer. The other mineral earths, talc, terra alba, whiting, china clay, or barytes are made into filler in the same manner.

To prepare for use, thin with turpentine or benzine to the required body.

Staining colors may be added when the base is being ground, or after thinning with turpentine benzine for use.

Paste fillers are adapted for open grained and hard woods and require rubbing with fine steel wool or sand paper, before the finishing coats of shellac or varnish are applied.