An Overview of Liquid Fillers

Certain surfacers on the market, called architectural fillers or liquid fillers, are not used very much in finishing furniture. They are suitable to apply as a sizing material for a first coat on many of the rather soft, close-grained woods that have inconspicuous cell openings. Less labor is required in the application of this type of filler, because it is painted on much like a coat of varnish, and is not rubbed off.

Liquid filler obscures the grain to some extent because the silex or coarse material, although nearly transparent when mixed with linseed-oil, is stuck to the surface by varnish, instead of being left only to fill the large open pores, as is the case with paste fillers. Liquid fillers are quite commonly used on the less expensive soft woods, when a cheap finish is wanted.

They are satisfactory as a first coat on many kinds of wood, especially in finishing the woodwork of houses; but they are not suitable to use on oak, ash, or other woods with large, conspicuous, open pores. An experienced wood finisher will usually make one gallon of liquid wood-filler cover about 250 square feet of surface.

The ingredients found in liquid fillers vary greatly, especially in the amount of silica (or silex) and varnish contained. Some liquid fillers are nearly pure varnish with the addition of small amounts of body materials, such as silica or whiting (calcium carbonate), together with some drier and thinner. Other liquid fillers are much like a thin paste filler, with only a small amount of varnish added to the mixture.

A filler that has a lot of varnish in its composition may be made up as follows:

· 1 quart varnish of frood grade, as a rubbing-varnish

· 1 pint light brown Japan

· ¼ to ½ pint turpentine

· 1.5 pounds light or floated silica (much less silica may be used)

The ingredients found in liquid fillers vary greatly, especially in the amount of silica (or silex) and varnish contained. Some liquid fillers are nearly pure varnish with the addition of small amounts of body materials, such as silica or whiting...