Adhesion: The property that causes one material to stick to another. Adhesion is affected by the condition of the surface to be coated and by the closeness of contact, as well as by the molecular forces of the unlike subtances. Thus, the surface should allow a certain amount of penetration, should be chemically clean and not too smooth, hard or non-porous for goood adhesion.
Problem: Air Entrapment
Problem: Benard Cells
Blistering: The formation of bubbles or pimples on the surface of finished work. Caused by exposure to excessive heat, by grease or other volatile material under the finish, by moisture in the wood or by the too frequent application of coats. Anything that causes a gas or vapor to form under the film may cause blistering.
Bloom: A bluish cast that forms on the surface of a dried film of finishing material. May be caused by a deposition of smoke or other foreign material from the atmosphere or by the softening of the film during rubbing operations, thus allowing traces of oil to remain on or in the surface which later sweat out to form a hazy film.
Blushing: The formation of a white or grayish cast in a spirit varnish, shellac or lacquer film during the drying period. Caused by the partial or total precipitation of the solid ingredients as a result of condensed moisture in the film because of excessive humidity or by improper solvent balance, resulting in the true solvents evaporating first and the diluent or non-solvent portion evaporating later. In either case, the addition of a quantity of slow evaporating true solvent, known as a
Bubbling: The appearance of bubbles in the film while a material is being applied. Caused by any condition that causes air, vapors, or gases to be trapped in the film while it is soft but after it has hardened sufficiently to prevent the gas from escaping.
Cracking: An intensified or advanced stage of checking or crazing whereby the breaks in the film are so deep as to expose the underlying surface.
Seeding: The formation of grains of undissolved resins in a varnish or lacquer or the formation of pigment aggregates from small individual particles in a paint caused by sever chilling or improper thinners.
Orange-Peel: A pebbled surface similar to that of an orange skin. Caused by the coating not leveling out completely after application by spraying.
Lifting: The softening and penetraion of a dried film by the solvent action of a second film applied over it in such a manner as to cause rising and wrinkling of the previously dried first coat.
Problem: Off Color
Pinholing: The appearance of fine pimply defects in a dried film, due to bubbles or other causes, which result in small holes in the film after the tops have been removed by rubbing or sanding.
Printing: The impression left in a film of dried finishing material after pressure has been removed.
Runs: Defects in a dried film caused by an excessive amount of material being applied, usually in an uneven manner, so that a portion of the material flows down in an irregular or curtained effect.
Sags: Irregularity of film thickness due to uneven flow.
Scratches: Slight incision, breaks, tears or indentations on the surface caused by abrasive friction.
Settling: The separation of a pigment or other solid ingredient from a coating material upon stabnding.