Penetrating finishes stains

Penetrating finishes such as stains and water-repellent preservatives ( 7,8) leave little or no continuous coating on wood surface. Because there is no coating, there is no failure by blistering or peeling. These finishes are ideally suited for rough-textured surfaces difficult to paint effectively. 

Two basic types of finishes (or treatments) are used to protect wood surfaces during outdoor weathering those that form a film, layer, or coating on the wood surface, and those that penetrate the wood surface to leave no distinct layer or coating. Film-forming materials include paints of all description, varnishes, lacquers, and also overlays bonded to the wood surface. Penetrating finishes include preservatives, water repellents, pigmented semitransparent stains, and chemical treatments. 

Waterborne Salts. Waterborne inorganic salts are a special group of penetrating finishes. These surface treatments result in a finish similar to the semitransparent penetrating finishes because they change the color of the wood and leave a surface deposit of material similar to the pigment found in the semitransparent stains. 

Penetrating Finishes. Penetrating finishes, which do not form a film over the wood, include oils, water repellents, stains, preservatives, and surface treatments. 

Penetrating finishes such as stains and water-repellent preservatives leave little or no continuous coating on wood... 

Coffee stain has remained a formidable challenge, A protective fluorinated finish retards the diffusion of the stain into fibers. However, when coffee penetrates the fluorinated repellent finish, stain-resist agents in the fibers must hinder staining by coffee. 

For penetration stain, a 0.5 mm thick veneer of white, non-discolouring rubber, is applied under pressure to a sheet of the test rubber and the composite vulcanized. A test piece cut from the composite sheet is exposed to artificial light and examined for staining. The composition of the white veneer is left for agreement between the interested parties. Alternatively, part of a finished product incorporating a veneer may be used or the rubber test piece without the veneer coated with a non-staining white laquer. 

Most stains used for finishing shingles and other nalural wood exlerior products are made with pigmented linseed oil. diluted with hytlrocarhon solvents for penetration. 

Weather affects the performance of wood finishes adversely. Both types of finish the film-forming (paints, varnishes) and the penetrating (stains, preservatives) are adversely affected by a combination of the following factors ... 

Finishes or stains that penetrate wood surface and form no coating also provide protection from weather. Because these types of finishes do not fail by peeling and blistering, they are more easily maintained and refinished. 

Opaque Stains. Solid color or opaque stains are another classification of finishes sometimes inaccurately described as natural wood finishes. These finishes are high in pigment content and completely mask the color and figure of the wood. Surface texture is retained and these finishes yield a flat appearance. They do protect wood against UV degradation, but tend to perform more like paints in that they do not penetrate the wood surface to any degree. 

Solid-Color Stains, Solid-color stains are opaque finishes (also called hiding, heavy-bodied, and opaque stains) that come in a wide range of colors and are made with a much higher concentration of pigment than the semitransparent penetrating stains. As a result, solid-color stains totally obscure the natural wood color and grain. Oil-based or alkyd solid-color stains form a film much like paint, and consequently they can peel from the substrate. Latex-based solid-color stains are also available and likewise form a film. Both oil-based and latex-based solid-color stains are similar to thinned paints and can usually be applied over old paint or semitransparent stains. 

Penetrating stains are suitable for both smooth and rough surfaces. However, their performance is markedly improved if applied to roughsawn, weathered, or rough-textured wood 4, 96, 99, 112, 136, 137, 141-144) because more material can be applied to such surfaces. They are especially effective on lumber and plywood that does not hold paint well, such as flatgrained and weathered surfaces, or dense species. Penetrating stains can be used effectively to finish such exterior surfaces as siding, trim, exposed... 

Foam technology is used to apply stain release chemicals to carpet. Liquid solutions normally used for treatment are replaced with foams. Wet pickup is lowered to as little as 8% in special applications, compared to 100% wet pickup in conventional methods [72]. The minimum pickup level for good finish penetration on cotton and cotton blends is about 45% [71], The reduction in water use at one plant was 20 million liters per year, and energy was cut 10% overall [72], However, foam and the surfactants necessary to produce it have their own set of problems in wastewater. 

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