Although the paint is beautiful, rust is leaking from the overlaps of the boards and the seams of the welds. The cause is the residual pretreatment solution and water in the gaps. Measures will be explained.
Brown rust juice has emerged from the seams of the painted parts. You might be wondering why, even though the paint looks nice. 【First, take a look here】 □ Rust juice only comes from overlapping plates or welded seams → Pre-treatment liquid or water is remaining in the gaps □ After baking, there were traces of bubbles or liquid at the seams → The liquid inside is being forced out by heat □ The paint has not reached deep into the gaps → The metal inside is left exposed 【Why does this happen?】 Liquid that enters narrow gaps is difficult to remove even with washing and does not dry completely. The remaining liquid causes the metal inside to rust, leading to rust juice seeping out later. 【Countermeasures you can implement starting today】 1. Hang the parts in a direction that allows the liquid to drain out 2. Allow for longer drainage and drying times 3. Consult during the design phase to create shapes that do not have gaps or include drainage holes 【Free Material】 We have compiled how to identify rust and countermeasures in the related catalog "Eiwa Kogei_Painting Trouble Introduction_Identification and Countermeasure Guide." You can download it for free from this page.
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Defects: Rust juice/rust from seams. Management items: Hanging direction, drainage, drying time, gap design, drainage holes.
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Purchasing personnel, design personnel, and quality assurance personnel responsible for arranging the painting of sheet metal and welded structural products. Measures against rust complaints after delivery.
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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.
