This standard specifies the tools, methods, quality evaluation, and coating environment, sanitation, and safety requirements for brushing organic coatings. This standard applies to brushing construction of organic coatings, and the brushing construction of inorganic coatings and oils can also refer to this standard. Where there are special requirements in product drawings or design documents, brushing construction should be carried out in accordance with the product requirements. JB/T 7706-1995 General Technical Specifications for Brushing Organic Coatings JB/T7706-1995 Standard download decompression password: www.bzxz.net
This standard specifies the tools, methods, quality evaluation, and coating environment, sanitation, and safety requirements for brushing organic coatings. This standard applies to brushing construction of organic coatings, and the brushing construction of inorganic coatings and oils can also refer to this standard. Where there are special requirements in product drawings or design documents, brushing construction should be carried out in accordance with the product requirements.

Mechanical Industry Standard of the People's Republic of China
General Technical Specifications for Brushing Organic Coatings
1 Subject Content and Scope of Application
JB/T7706—1995
This standard specifies the tools, methods, quality evaluation, and coating environment, hygiene, and safety requirements for brushing organic coatings. This standard is applicable to the brushing of organic coatings, and the brushing of inorganic coatings and oil products can also refer to this standard. If there are special requirements in the product drawings or design documents, the brushing construction should be carried out in accordance with the product requirements. 2 Reference standards
GB6514 Safety regulations for painting operations Paint process safety GB6515 Safety regulations for painting operations Ventilation and purification of painting processes GB6807
Technical conditions for phosphating of steel workpieces before painting Safety regulations for painting operations Labor safety and labor hygiene management GB7691
Technical terms for painting
GB8264
GB8923
Rust level and rust removal level of steel surfaces before painting QB1103 Pig Xin paint brush
3 Terms
3.1 Brush marks: as defined in Article 5.44 of GB8264. 3.2 Sagging: as defined in Article 5.57 of GB8264. 3.3 Bubbles: During the painting process, one or more bubbles are formed on the surface of the paint coating due to the air entrained by the paint brush. 3.4 Pinholes: as defined in Article 5.55 of GB8264. 4 Pre-treatment before painting
The pre-treatment of the surface for painting can be mechanical or chemical. 4.11
4.2 If mechanical pre-treatment is used, the surface quality should exceed Sal or St2 of GB8923. 4.3 If chemical pre-treatment is used, the rust, scale and oil on the surface should be completely removed to completely expose the surface of the substrate. 4.4 For surfaces that need phosphating, the provisions of GB6807 shall be followed. 4.5 The surface to be painted with old coatings should be sanded with sandpaper to roughen the coating surface and ensure the adhesion of the coating. 4.6 After removing the oil and dust on the surface of wood materials and other non-metallic materials, materials with high moisture content should be dried to make their moisture content lower than the maximum limit that will not affect the coating construction and coating performance. 5 Painting tools
The tool used for painting is a brush.
5.1 The raw hair of the brush is commonly pig, and there are also wool, horsetail, wolf hair, hair, human hair, palm silk, etc. 5.2 Brushes are divided into hard brushes and soft brushes according to the raw hair they use. Hard brushes are usually made of pig hair; soft brushes are usually made of wool. Brushes can be divided into flat brushes, round brushes and curved handle brushes according to their appearance. See Figure 1 for their appearance. Approved by the Ministry of Machinery Industry on June 20, 1995
Implementation on January 1, 1996
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Straight brush
JB/T 7706--1995
Curved brush
Round brush
Figure 1 Shape of brush
Flat brush
5.3 The width of the brush is (9~~150) mm. Pig paint brushes must comply with the provisions of QB1103. Other types of brushes can refer to the pig paint brush standard.
6 Technical requirements for brush painting
6.1 Preparation before brush painting
6.1.1 When a new brush is used for the first time, dip the base of the brush into a solvent-resistant polyurethane varnish and solidify it to prevent the brush from shedding during brush painting.
6.1.2 In order to make the brush have good paint resistance, use your fingers to repeatedly brush the bristles upwards several times before use, pull out the fallen bristles, then apply a small amount of paint on the pallet to fully spread it, then use a wooden scraper to spread the brush, and finally rub it on sandpaper to make the brush flat. Note: Spread: Wipe along and arrange the bristles to make them neat. 6.1.3 Before brushing, stir the paint by hand or mechanical means to mix it thoroughly. If the paint is found to be crusted or has particles, the crust should be removed and filtered with a filter.
6.2 Brushing operation
When brushing, immerse the brush into the paint to 4/5 of the length of the brush, lift the brush and lightly press or scrape the inner side of the paint, and then quickly use the brush to shave the coating surface in the following three steps: 6.2.1 Form the required full coating: Keep the brush at an angle of 45°~60° with the coating surface, and brush the coating on the coating surface evenly and comprehensively. Use a small brush to pre-coat the difficult-to-coat parts. 6.2.2 Form a continuous coating with uniform thickness: Use a brush that squeezes out excess paint to brush in one direction first, and then brush in a vertical direction. 6.2.3 Make the coating film flat and drive away bubbles: Use a brush that squeezes out excess paint to gently brush in one direction until there are no bubbles in the coating film.
For volatile fast-drying paints (such as shellac paint and nitro paint), use a soft brush to brush in blocks, that is, divide the coating surface into several blocks, and brush each block according to the above three steps. When brushing, the action should be brisk and accurate, and try to avoid brushing back to prevent biting or brushing. Each piece of brushing should overlap with the previous piece by 1/3 of the brushing width. Until the entire coating surface is brushed. 6.3 After brushing, the brush should be fully rubbed and cleaned in a thinner, and then hung for storage. 7 Brushable paint and its viscosity range
All liquid paints (except electrophoretic paint) can be brushed, and their viscosity range is relatively wide. The appropriate construction viscosity for brushing should be so that the paint raised by the brush will not flow down from the bristles quickly, the paint will flow out of the bristles when the brush is pressed on the coating surface, the brushing should be brisk, and the paint should flow well.
8 Requirements for brush coating
The brush coating should be flat, the thickness and surface gloss should be uniform, and there should be no obvious color difference, brush marks, sagging, bubbles and pinholes. Others shall comply with the technical indicators of coating products and the provisions of product process documents. 9 Environment, safety and sanitation 9.1 The safety of brush painting shall comply with the requirements of GB6514. 9.2 The sanitation of brush painting shall comply with the requirements of GB7691. 9.3 The environment of brush painting shall comply with the temperature and humidity requirements of the paint factory for the paint construction environment, and the ventilation and purification shall comply with the requirements of GB6515.
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Control parameters of substrate moisture content
JB/T7706-—1995
Appendix A
Recommended parameters for brush painting
(reference)
Materials with high moisture content must be dried before brush painting. For wooden parts, the moisture content should be controlled at 8%-12%. For coatings with special requirements, their moisture content should be determined strictly according to the coating construction technical parameters. Brush application viscosity
The applicable viscosity range of the coating during brush application is very wide, and the construction is greatly affected by the operator's subjective and objective environment. Under the environmental conditions of 25℃±1℃, the recommended construction viscosity is shown in the table below. Table A1 Brushing application viscosity values ??of several commonly used coatings (coating -4 cups, 25℃±1℃) Coating types
Nitrocellulose paint
Perchloroethylene paint
Phenolic paint
Acid paint
Epoxy paint
Polyurethane paint
Chlorinated rubber paint
Viscosity value/s
10~15
12 ~18
25～35
25 ~35
25~35
20~35
25-40
When there are special requirements or environmental conditions change, the best application viscosity can be determined by the construction personnel through experiments. Additional remarks:
This standard is proposed by the National Technical Committee for Standardization of Metal and Non-metal Coverings. This standard is under the jurisdiction of Wuhan Institute of Materials Protection and is responsible for drafting. The main drafter of this standard is Jun Xiaochun.
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