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Prevention and Control of Common Paint Issues

Categories:Customer service
Time of issue:2020-07-15 00:00:00
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(I) Prevention and control of common “paint issues”

“Paint issues” can be divided into paint film defects from coating and storage after coating.

1. Sagging (Running, flowing and dropping)

As a common defect in coating works, sagging appears in primer, intermediate paint, finish paint or strip paint and its symptoms include flaked paint film dropping and tear stain. See the table below for its causes and solutions.

Causes	Precautions and Solutions
Construction is improper, a spray gun is too close to the surface of a painted object and gun moving speed is too slow	Improve operators’ skills and control painting distance of various work-piece and gun moving speed
Primary paint film is too thick	Control paint film thickness according to the process requirements
Coating has low viscosity or too many diluents are added, causing extremely low painting viscosity	Control construction viscosity of coating strictly and adopt supporting diluent to regulate viscosity
Painting pressure is too high and spray gun moving speed is too slow (flaked flowing)	Control pressure to qualified range and maintain proper gun moving speed
Interval between wet-on-wet painting is too short	Comply with construction process strictly and guarantee sufficient drying time
Surface of a painted object is uneven, surface treatment is poor or oil stain exists	Guarantee surface treatment quality
Paint film is too smooth	Grind before painting strip paint
Spray gun has low pressure and nozzle has big caliber	Spray gun pressure and nozzle caliber shall meet process requirements

2. Whitened Film

Causes	Precautions and Solutions
Construction has too much humidity and diluent has extremely rapid volatilizing speed	In case of too much humidity, construction shall not be conducted, the painting room shall be heated before construction or desiccant shall be adopted for prevention and control. Diluent shall be prepared from organic solvent with high boiling point and slow volatilizing speed
Painting equipment contains too much moisture	Remove moisture in the painting equipment
Temperature of the painted object is below the room temperature	Heat the painted object work-piece before coating to make its temperature above the environment temperature
Coating or diluent contains moisture	Coating or diluent used shall contain no moisture
	In case of a whitened phenomenon, finish paint shall be ground before painting it again to eliminate the phenomenon

3. Poor Covering Power and Exposed Base

Causes	Precautions and Solutions
Coating selected has poor covering power	Select coating with good covering power for construction or improve pigment of colored paint
Coating has sediment and has not been mixed sufficiently before utilization	Coating shall be mixed sufficiently before utilization
Painting is too thin or painting times is too few	Painting thickness and passes shall meet coating requirements
Construction has extremely low viscosity or primer and finish paint have big color difference	Regulate proper construction viscosity; colors of primer and finish paint shall be similar
	In case of exposed base, it can be covered by another finish paint

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Prevention and Control of Common Paint Issues

Chongqing Sanxia Paints Co., Ltd.