What causes the increase in small holes when it gets cold? Moisture in cooled parts.
When cold parts are placed in a warm painting area, moisture that has condensed on the surface gets trapped in the paint film, leading to holes during curing. This explains how to identify the increased number of holes in winter.
Since it has gotten cold, small holes have been increasing on the painted surfaces. The paint and gun settings should be the same as in summer. 【First, please look here】 □ Common on parts painted immediately after being taken out of the warehouse → There is invisible condensation on the surface of the cooled parts □ Holes appear after baking, and the surface looks clean right after painting → Trapped moisture expands with heat and creates holes in the paint film □ Concentrated around castings and welded areas → Moisture that has entered the gaps has not completely evaporated 【Why it happens】 When cooled parts are moved to a warm place, tiny water droplets form on the surface. If painted over, the moisture expands with the heat from baking, creating holes in the paint film. 【Countermeasures that can be implemented starting today】 1. Bring parts into the painting area the day before to acclimate to the temperature 2. Check the surface temperature of the parts before painting 3. Preheat castings and welded items to evaporate moisture before painting 【Free Material】 We have compiled how to identify painting troubles, including holes, in the related catalog "Eiho Kogei_Painting Trouble Introduction_Identification and Countermeasure Guide." It can be downloaded for free from this page.
basic information
Defect targets: pinholes, seams. Management items: component delivery time, surface temperature of components, preheating, moisture in castings and welds.
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Applications/Examples of results
Casting, welded structures, and powder coating of metal parts stored outdoors or in warehouses. Measures for defects in winter, seasonal transition standards for the quality control department, and training materials for new employees.
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We are not just a "subcontracted painting factory." Established in 1958, our company has a foundation of painting technology and also specializes in chemical treatment, stripping, and cleaning, functioning as the "external surface treatment department" in your organizational chart. Based on our philosophy of "preparation is eight-tenths of the work," we emphasize participation from the "upstream process" before the drawings are finalized. We conduct test painting on a wide range of metals and difficult materials, and we produce the entire process from assembly, packaging, to delivery, thereby reducing your management workload. Additionally, by being able to perform zinc phosphate treatment in-house, we achieve stable painting quality. Furthermore, our micro-heating stripping technology, which does not use chemicals, maintains the electrical state of the "jigs (hangers)" that influence painting quality. Our approach of "pre-treatment determines painting quality" ensures the stability of the paint film during mass production. Rather than simply "applying specified standards," we work backwards to achieve optimal painting specifications and prevent scratches during transportation, sparing no effort in thorough discussions from the outset. This diligent preparation is the shortest path to preventing rework and minimizing total costs. From the development stage, please utilize the expertise of our specialists as part of your production line.