topcoats. Sealers are used on wood to prevent resin
running or bleeding. Fillers are used to produce a
smooth finish on open-grained wood and rough ma-
sonry. Table 8-1 presents the satisfactory treatments of
the various surfaces.
Since water-thinned latex paints do not adhere well
to chalky masonry surfaces, an oil-based conditioner is
applied to the chalky substrate before latex paint is
applied. The entire surface should be vigorously wire
brushed by hand or power tools, then dusted to remove
all loose particles and chalk residue. The conditioner is
then brushed on freely to assure effective penetration
and allowed to dry. Conditioner is not intended for use
as a finish coat.
SEALERS
Sealers are applied to bare wood like coats of paint.
Freshly exuded resin, while still soft, may be scraped
off with a putty knife and the area cleaned with alcohol.
Remove hardened resin by scraping or sanding. Since
sealer is not intended as a prime coat, it should be used
only when necessary and applied only over the affected
area. When previous paint becomes discolored over
knots on pine lumber, the sealer should be applied over
the old paint before the new paint is applied.
FILLERS
Fillers are used on porous wood, concrete, and
masonry to provide a smoother finish coat.
Wood
Wood fillers are used on open-grained hardwoods.
In general, hardwoods with pores larger than those
found in birch should be filled. Table 8-2 lists the
characteristics of various woods and which ones
require fillers. The table also contains notes on
finishing. Filling is done after staining. Stain should
be allowed to dry for 24 hours before the filler is
Table 8-2.-Characteristics of Wood
8-7
