What causes painted products to rust immediately after delivery? Chemical treatment and film thickness at the corners.
Rust appeared on the painted products shortly after delivery. The cause is related to the chemical treatment during pre-processing and insufficient film thickness at corners and holes. This explains how to identify the issue and the countermeasures.
We received a report that rust has already appeared on the painted items that were just delivered. Why is it rusting so quickly despite being painted? 【First, please look here】 □ Rust is appearing from the corners and edges → The corners have a thin layer of paint, and the film thickness is insufficient. □ Small dot-like rust is scattered across the surface → Water is entering through pinholes in the paint film. □ Rust is spreading underneath the paint film → There is no chemical treatment, and the rust prevention of the substrate is weak. 【Why does this happen?】 The paint film allows water to pass through thin areas and holes. Iron that has not undergone chemical treatment will rapidly rust from those points. 【Countermeasures that can be implemented starting today】 1. Specify chemical treatment such as zinc phosphate for iron parts. 2. Add corner beveling and check the film thickness at the corners. 3. Dry the items before packaging to prevent condensation. 【Free Material】 We have compiled a guide on how to identify painting troubles that include rust in the related catalog "Eiwa Kogei_Painting Trouble Introduction_Identification and Countermeasure Guide." It can be downloaded for free from this page.
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basic information
Defect target: Early rust. How to identify: Location and shape of rust. Management items: Chemical treatment (such as zinc phosphate), corner film thickness, chamfering, drying before packaging.
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Applications/Examples of results
Painting of iron parts, frames, brackets, and metal products for outdoor use. Handling rust complaints from sales representatives and quality assurance personnel, and reviewing painting specifications.
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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.
