The painting process of the valve
Pretreatment before painting, mixing the paint, applying the primer, applying the finish paint and inspection
2.1 Pretreatment before painting
1) The surface of the valve body should be treated in strict accordance with the surface of the substrate required by the paint manufacturer or the customer.
2) Before surface treatment, oil, welding slag and rust on the surface of the valve body should be removed.
3) Surface treatment must be carried out at temperatures 3°C above the dew-point temperature and below 80% of relative humidity.
2.2 Mixing the paint
2.3 Applying the primer
The coating conditions should meet the requirements of the painting manual. Strictly follow the requirements of the painting manual for weight ratio or volume ratio. The temperature of the substrate must be 3°C more than the dew-point temperature. When the temperature of the substrate is lower than 5°C, the paint film is not easy to be solidified.
The main agent and the curing agent should be stirred and mixed evenly. After the curing agent is added to the main agent, continuously stir them. The diluent should be added according to the proportion. The diluent must be selected according to the corresponding model and specification. Mix them well, and left to stand. After curing, add an appropriate amount of diluent with construction viscosity.
Depending on the painting tool selected such as brush, air spraying, hand spraying and thickness of the coating, choose different painting times, generally 2 to 3 times. Recommended film thickness are 60 to 80um. The coating interval is determined by the specific instructions for use of different paints. After the primer is done, apply an emery cloth or sandpaper to make the primer smooth.
2.4 Applying the finish paint
1) Check whether the overcoating interval of the primer meets the requirement. Check the dryness of the underlying workpiece’s surface, and remove the dirt on the paint film.
2) The ratio of the main paint to the diluent or curing agent, and the curing time should be carried out in accordance with the requirements of the painting manual.
3) The time the paint can be used after mixing depends on the specific type of paint.
4) After the paint is laid aside, the repainting time should be strictly in accordance with the repainting time and drying time of the paint.
5) After the coating tool is used, it should be cleaned with diluent to avoid difficult cleaning after curing.
2.5 Inspecting the coating
The thickness of the paint for the non-machined surface of the valve:
Primers: iron red anti-rust primer with a film thickness of 40 to 80um.
Finishing coat: ordinary two-component finishing coat with a film thickness of 25 to 40um.
The painting should be smooth free from blistering, pinholes, scratches or any irregularities and has uniform colors after visual inspection. The painting of the valve should be durable and beautiful, and ensure that the sign of the valve is clear.
Pretreatment before painting, mixing the paint, applying the primer, applying the finish paint and inspection
2.1 Pretreatment before painting
1) The surface of the valve body should be treated in strict accordance with the surface of the substrate required by the paint manufacturer or the customer.
2) Before surface treatment, oil, welding slag and rust on the surface of the valve body should be removed.
3) Surface treatment must be carried out at temperatures 3°C above the dew-point temperature and below 80% of relative humidity.
2.2 Mixing the paint
2.3 Applying the primer
The coating conditions should meet the requirements of the painting manual. Strictly follow the requirements of the painting manual for weight ratio or volume ratio. The temperature of the substrate must be 3°C more than the dew-point temperature. When the temperature of the substrate is lower than 5°C, the paint film is not easy to be solidified.
The main agent and the curing agent should be stirred and mixed evenly. After the curing agent is added to the main agent, continuously stir them. The diluent should be added according to the proportion. The diluent must be selected according to the corresponding model and specification. Mix them well, and left to stand. After curing, add an appropriate amount of diluent with construction viscosity.
Depending on the painting tool selected such as brush, air spraying, hand spraying and thickness of the coating, choose different painting times, generally 2 to 3 times. Recommended film thickness are 60 to 80um. The coating interval is determined by the specific instructions for use of different paints. After the primer is done, apply an emery cloth or sandpaper to make the primer smooth.
2.4 Applying the finish paint
1) Check whether the overcoating interval of the primer meets the requirement. Check the dryness of the underlying workpiece’s surface, and remove the dirt on the paint film.
2) The ratio of the main paint to the diluent or curing agent, and the curing time should be carried out in accordance with the requirements of the painting manual.
3) The time the paint can be used after mixing depends on the specific type of paint.
4) After the paint is laid aside, the repainting time should be strictly in accordance with the repainting time and drying time of the paint.
5) After the coating tool is used, it should be cleaned with diluent to avoid difficult cleaning after curing.
2.5 Inspecting the coating
The thickness of the paint for the non-machined surface of the valve:
Primers: iron red anti-rust primer with a film thickness of 40 to 80um.
Finishing coat: ordinary two-component finishing coat with a film thickness of 25 to 40um.
The painting should be smooth free from blistering, pinholes, scratches or any irregularities and has uniform colors after visual inspection. The painting of the valve should be durable and beautiful, and ensure that the sign of the valve is clear.
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