What causes painted items to rust quickly in winter? The temperature of the chemical treatment solution.
During cold periods, the temperature of the chemical treatment solution decreases, resulting in a thinner and uneven coating. This explains the subtle decline in rust prevention during winter and the key points for managing solution temperature.
It seems that only the parts painted in winter rust faster. The appearance of the paint is no different from summer. 【First, please look here】 □ The color after chemical treatment is lighter and mottled than usual. → The liquid temperature has dropped, and the film has not formed sufficiently. □ Parts treated first thing in the morning are more prone to rust. → They are being processed before the temperature of the treatment tank has fully risen. □ Rust spreads from underneath the paint film. → The rust prevention capability of the substrate has weakened. 【Why does this happen?】 Chemical treatments like zinc phosphate vary in film formation depending on the liquid temperature. When the liquid temperature is low, the film becomes thin and uneven, making it easier for rust to spread underneath the paint film. 【Countermeasures you can take starting today】 1. Measure and record the temperature of the treatment tank at the start of work and at noon. 2. Compare the color after chemical treatment with a sample to confirm. 3. In winter, start heating the tank earlier. 【Free Materials】 We have compiled the standards for process management, including chemical treatment, in the related catalog "Eiwa Kogei_Paint Quality Control Guidelines_Process Management Standards." You can download it for free from this page.
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basic information
Defect target: Early rust, reduced adhesion. Management items: Liquid temperature of chemical treatment (such as zinc phosphate), confirmation of color after treatment, heating time of the tank.
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Applications/Examples of results
Painting of iron parts, frames, and metal products used outdoors. Management of rust prevention quality in winter, auditing of pre-treatment processes, and training materials for new employees.
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Company information
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.
