5-26. CRAWLING OR CREEPING
Characteristics. Crawling or creeping of paint is noted by little drops (or islands) which form on the paint film.
Probable Cause. Crawling often occurs when varnish or enamel is applied on an oily or greasy surface. Painting
over a very smooth surface will sometimes cause crawling.
Corrective Measures. Remove the little islands of paint which have formed on the film by sanding them, and
wash off any grease or oil which may be underneath. If a glossy coat has been applied over another glossy coat, remove
both coats using varnish and paint remover. Apply a prime coat without gloss before applying a high gloss topcoat.
Characteristics. Dulling is characterized by the loss of gloss which should be present in a high gloss varnish,
paint, or enamel film after it has dried.
Probable Cause. Dulling may be caused by the action of gases, inferior products, use of very old stock, or the
use of too much turpentine or thinner.
Corrective Measures. Remove the dulled coat, or sand it down with fine sandpaper, and apply a varnish, paint or
enamel of known good quality.
Characteristics. Mildew is a fungus frequently found on exposed surfaces in warm, damp climates, particularly on
soft paint films.
Probable Causes. Paint film that has become sticky or tacky attracts windblown spores and decayed and dried
vegetation to its surface. The oil in the paint sometimes becomes infested, and the breeding of mildew spores takes
Corrective Measures. To prevent the recurrence of mildew, the old coat of paint should be removed and a new
coat of hard-drying paint applied. A fungus growth can be partially removed by scrubbing the affected surface with a
solution of trisodium phosphate and water. The surface should then be rinsed with clear water and allowed to dry. The
use of less paint and more thinner is advised in environments where mildew is a common occurrence.
Extreme care must be observed in the handling of paints containing mercury or
other fungicides to prevent poisoning or skin irritation.
5-29. STREAKING AND LUMPING
Characteristics. Streaks or lumps on painted wood surfaces are caused by resin and pitch exuding from knots
and unseasoned lumber.
Probable Causes. This condition is caused by painting over unseasoned lumber and by painting over knots or
resinous streaks which have not been properly treated before painting. On metal, it is an indication that the paint has
been applied incorrectly.