Stain rough surfaces

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... 

Corrosion resistant steel (CRES) (300-400 series) Intergranular corrosion (due to improper heat treatment). Some tendency to pitting in marine environment (300 series more corrosion resistant than 400 series). Stress corrosion cracking Corrosion evidenced by rough surface sometimes by red, brown, or black stain... 

Poor preparation of the substrate can result in loss of adhesion, pitting, roughness, lower corrosion resistance, smears, and stains. Because electroplating takes place at the exact molecular surface of a work, it is important that the substrate surface be absolutely clean and receptive to the plating. In the effort to get the substrate into this condition, several separate steps may be required, and it is in these cleaning steps that most of the problems associated with plating arise. 

Figure 1-3 A cell of a Spirillum negatively stained with phosphotungstic acid. Note the tufts of flagella at the ends, the rough appearance of the outer surface, the dark granules of poly-(3-hydroxybutyric acid and the light-colored granules of unknown nature. Courtesy of F. D. Williams, Gail E. VanderMolen, and C. F. Amstein.

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. 

The formation of porous layers in silicon by chemical etching in HF/HNO3 solutions was first reported at about the same time as electrochemical etching [101-104]. These so-called stain etch films are characterized by rough or porous surfaces, typically < 500 A in thickness. Recent work has shown that these stain etch films exhibit strong visible photoluminescence, similar to the emission observed from electrochemically etched porous silicon layers. 

Effect of Surface Roughness and Oxides on Pitting of Stain Iess Steeis... 

B. Sodium hydroxide—ethyl alcohol solution is prepared with 2.5 g of sodium hydroxide plus 40 mL of water plus 10 mL of ethyl alcohol. If the contact of the polished surface with the solution is more than roughly 20 seconds, a deposit from a reaction between hydroxide and aluminate forms that buffing will not remove. CjA turns blue. If determination of alkali sulfates is desired, stain only one time for approximately 10 seconds, washing with 1 1 ethyl alcohol water solution, followed by isopropyl alcohol. Do not buff. This treatment will darken alkali sulfates slightly and with prolonged treatment (as for CjA) will dissolve the alkali sulfate, producing a dark void. 

The effect of atmospheric humidity on the corrosion of zinc is related to the conditions that may cause condensation of moisture on the metal surface and to the frequency and duration of the moisture contact. If the air temperature drops below the dew point, moisture will be deposited. The thickness of zinc, its surface roughness, and its cleanliness also influence the amount of dew deposited. Lowering the temperature of a metal surface below the air temperature in a humid atmosphere will cause moisture to condense on the metal. If the water evaporates quickly, corrosion usually is not severe and a protective film is formed on the surface. If water from rain or snow remains in contact with zinc when access to air is restricted and the humidity is high, the resulting corrosion can appear to be severe (wet storage stain, popularly known as white rust ), since the formation of a protective basic zinc carbonate is prevented. 

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