A brief analysis of the construction process of cement products special paint (latex paint).

There are many types of coatings, different types of coatings have different construction process requirements, today we together analyze the cement products special paint (water-based latex paint) construction process and precautions, I hope to help you.
1 construction requirements
(1) substrate requirements: cement products maintenance for about 20 days, alkalinity pH value of less than 9, while the grass has been dry (at least 15 days dry), humidity is less than 8%;
(2) the paint used has a factory certificate, at the same time, after testing to meet the requirements of the relevant national norms and standards
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(3) paint used by the owner, supervision and design unit consent, while spraying model seal.
(4) the grass-roots exposed iron has done a good job of the corresponding anti-rust treatment.
(5) construction conditions: cement products special paint because it is water-based paint, the construction maintenance conditions are higher. Construction and maintenance requirements temperature is higher than 5 degrees C, ambient humidity is less than 85%, to ensure good film forming. Low temperature will cause the paint film powder cracking and other problems, environmental humidity ambassador paint film for a long time not dry, and eventually lead to bad film. Exterior wall construction must take into account the weather factors, before painting paint, 12 hours did not rain, to ensure that the grass dry, after painting, 24 hours can not rain, to avoid paint film by rain.
2 exterior paint construction method
cement products coating system is divided into three layers, namely primer, finish, mask paint. Its role is as follows:
(1) primer (sealing paint): primer can close the alkalinity of the substrate, improve the paint adhesion, and correspondingly reduce the amount of paint, the opposite coating performance and surface effect has a greater impact. If you do not use primer, paint film adhesion will be weakened, the wall alkaline opposite paint performance has a greater impact, especially the use of reduced cement substrate, may cause paint film powdering, yellowing, seepage and other problems, damage paint performance, affect the life of paint film.
(2) paint: the main function of the paint is to decorate the function, increase the aesthetics of cement products, .
(3) mask paint: cover paint is the last coating in the system, improve the brightness and hardness of the paint, resist environmental violations.
2.1 Construction process
remediation→ cleaning→ local scraping putty→ grinding→ primer construction→ paint construction→ cover paint construction
3. Operating method
a, repair:
before application of the substrate defects such as missing corners, holes and other defects using 1:3 cement mortar (or cement polymer mortar). Here are the specific practices:
empty drum - if for a large area of empty drum, the empty drum parts are completely eliminated, cleaned up, re-do the grass, if the local empty drum, then with injection of low viscosity epoxy resin for repair.
gap - small cracks using putty to repair (repair requires a thin batch rather than a thick brush), dry sandpaper flattened, for large cracks, the crack site can be chiseled into a "V" glyph gap, cleaned clean and made a waterproof layer, and then embedded 1:2.5 cement mortar, dry after sanding paper.
holes - holes below 3mm below the base surface, using polymer cement putty to find flat, holes larger than 3mm using cement mortar for repair to be dried and flattened.
In addition to the new cement mortar surface, if the urgent need for painting, can be used 15%-20% concentration of zinc sulfate or zinc oxide solution applied to the cement mortar base surface several times, to be dried after removing the surface of the powder and floating sand can be painted.
b, cleaning:
dust, powder - can be cleaned with brooms, brushes, high-pressure blows, grease - using neutral detergents; mortar - removed with shovels, scrapers, etc.; mold - outdoor high-pressure water flushing, water rinsing needs to be dried.
c, fill putty, local scrape putty:
if the wall is flat, smooth, can not use putty; putty requirements in addition to easy to batch easy to polish, but also should have better strength and durability, in the filling, local scraping putty construction requirements, should be thin batch rather than thick brush. Putty should be more adhesive, durable and water resistant.
putty used in the plant is mixed with 107 glued white cement slurry plus 159d120M fine sand.
d, flat:
(1) can not be wet grinding, grinding must be done after the grass or putty drying, so as not to adhere to sandpaper affect the operation.
(2) the thickness of sandpaper should be determined according to the hardness of the ground surface, sandpaper thick will produce sand marks, affecting the final decorative effect of the coating.
(3) when sanding with a coarse sand cloth or grinder, and then with a fine sand cloth, pay attention to the flatness of the surface, even if the surface of the flatness meets the requirements.
(4) for uneven surface, the protruding part can be bulldozed, and then filled with putty, and so drying and then sandpaper for grinding. It is required that the flatness of the grass after grinding be reached with no obvious scraping marks, no roughness and smooth surface under the side light.
(5) grinding, the surface dust is removed immediately to benefit the construction of the next process.
e paint brushing:
paint painting requirements: the water content of the grass-roots surface shall not be greater than 8%, such as in the event of high winds, rain, fog and weather may not be applied surface coating;
(1) paint deployment
paint deployment should be in accordance with the requirements of the manufacturer, according to the color card selection for color matching. The dilution concentration of the paint should be adjusted according to the concentration of the original paint, construction weather and construction method,
in the degree of application, if the paint is found to have precipitation, it must be stirred evenly, the mixing of the paint is carried out by an electric mixer, stirring time control in 8-10 minutes is appropriate.
(2) application requirements:
coating is mainly sprayed, brushed and rolled: construction of each layer of paint should not be applied thick, the coating should be uniform, consistent color. Construction temperature should be higher than 5 degrees C, ambient humidity is less than 85%, to ensure good film. Low temperature will cause the paint film powder cracking and other problems, environmental humidity ambassador paint film for a long time not dry, and eventually lead to bad film. Outdoor construction must take into account weather factors, before painting paint, 12 hours can not rain, to ensure that the substrate dry, after painting, take appropriate measures to prevent the paint film due to rain within 24 hours caused by rain.
coating construction requires the previous coating table dry before the 31st brush, the front and rear two layers of painting time interval is less than 4 hours.
(3) coating skills,
to achieve good coating results, skilled operating level is necessary. First of all, the substrate requirements should be clean and dry and solid, according to the instruction manual operation, coating conditions suitable, the dilution ratio is accurate, excessive dilution will make the paint do not cover the bottom, powder, shiny paint will lose light, color is different. Secondly, good construction equipment is also necessary. Paint order to be first up and then down, each part of which must also be painted from top to bottom. Move quickly during the brushing process and spray back and forth from time to time at the dry and dry joints to avoid leaving layers or seams.
(4) brush after treatment
after the completion of construction, the tool needs to be cleaned immediately, while immediately cleaning accidentally contaminated items, otherwise the paint dry knot difficult to remove, will damage the tool. The remaining coatings are kept clean and sealed.
(5) quality requirements:
after the application of the coating requirements must not appear the following: no leakage, permeable, drop powder, peeling, pendants, molybons, at the same time must not appear anti-alkali, bite color, and color requirements consistent, dense and uniform.
4. Frequently asked questions and
(1) problems: anti-subtract, powdering, fading, peeling, shedding.
(2) Reason: a reverse reduction (paint surface appears a layer of white frost) is due to the construction did not according to the process requirements of brush sealing paint reduction;