news — from the mill.
Production notes, industry updates, and a little colour on what we’re making this month.
PPGI Coil 20-Year Warranty: Claim Conditions and Exclusions
When a supplier offers a 20-year warranty on PPGI coils, the fine print determines whether that promise has real value or is merely marketing language. In practice, a 20-year warranty typically covers only specific failure modes—such as corrosion penetration through the metallic coating or premature paint degradation—under strictly defined environmental and installation conditions. To file […]
Read →PPGI Coil Quality Checks: Pencil Hardness and T-Bend Testing Guide
Yes, you can perform meaningful pencil hardness and T-bend tests in your own warehouse to verify that incoming PPGI coils match the coating properties stated on the mill test certificate. These two tests are practical, low-cost, and require only basic hand tools. However, they are screening tools, not full laboratory certifications. To get reliable results, […]
Read →PPGI Coil Color Change After Bending: Stress Whitening Explained
Yes, the whitish or lighter color you see at the bend lines of your PPGI sheets is most likely a physical response of the paint film to stress, not a manufacturing defect in the coating itself. This phenomenon, commonly called stress whitening, occurs when the paint film is deformed beyond its elastic limit during forming. […]
Read →PPGI Coil Roll Forming: Oil Pickup and Coating Damage Prevention
Yes, the forming oil you use can interact directly with the paint system, and it is often the primary trigger for scratches and peeling—but it is rarely the only cause. Coating damage during roll forming is typically a combined result of lubricant chemistry, paint film hardness, metallic coating topography, and tooling setup. You cannot rule […]
Read →Why the Back Side of PPGI Coil Matters: Primer and Back Paint
When you order PPGI coils for roofing sheets in a humid climate, the back paint is not a cosmetic detail—it is a corrosion-control decision. The functional difference between epoxy, polyester, and primer-only systems is about moisture barrier performance, adhesion to the metallic coating, and formability. In short: a well-specified reverse-side coating can delay edge and […]
Read →PPGI Coil Paint Thickness: DFT vs. TBT in Coating Specs
If you are comparing quotes from PPGI suppliers and seeing some specify dry film thickness (DFT) while others specify total build thickness (TBT), the short answer is: you need to specify both, but DFT is the number that governs corrosion and durability performance. TBT is a useful process control check, but DFT per layer tells […]
Read →PPGI Coil: Total Landed Cost vs. Price Per Ton – The Real Procurement Math
When you compare PPGI coil suppliers, the price per ton is the first number you see, but it is rarely the number that determines your true material cost. The total landed cost—which includes freight, insurance, duties, financing, and handling—can shift your procurement decision by a significant margin. This article explains how to calculate that figure […]
Read →PPGI for Sandwich Panels: Core Adhesion Specifications
The single most critical PPGI coil specification for reliable sandwich-panel bonding is the backer coating system, not the topcoat. For polyurethane (PU), polyisocyanurate (PIR), and rockwool cores, the reverse-side paint must be formulated for chemical and mechanical compatibility with the specific adhesive or foaming process. In short, you need a PPGI with a dedicated reverse-side […]
Read →PPGI Roofing Screw Corrosion: Why Fasteners Fail and How to Avoid It
If you are asking, “Why are the screws on my PPGI roof corroding, and what type of fastener should I use to prevent this?” the short answer is that fastener failure is rarely about the screw alone. It is a system issue involving the metallic coating on the screw, the cut edge of the PPGI […]
Read →How to Ensure PPGI Color Consistency Across Batches
Color mismatch between PPGI coil batches is one of the most frequent and costly complaints in the prepainted steel supply chain. The short answer to preventing it is this: you must move beyond naming a RAL number and instead specify a measurable color tolerance, typically expressed as ΔE, along with a defined approval process for […]
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