news — from the mill.
Production notes, industry updates, and a little colour on what we’re making this month.
PPGI Coil for Standing Seam and Concealed Fix Roofing
Standard PPGI coil can be used for standing seam and concealed fix roofing, but only if it is specified as a forming-grade, coating-engineered product rather than a generic “colour-coated galvanised sheet.” The base PPGI concept is sound: a metallic-coated steel substrate with an organic paint system. What changes for standing seam is the combination of […]
Read →PPGI Roll Forming Line Settings That Protect the Coating
To stop a PPGI coil from scratching, cracking or marking during profiling, set the line so that the paint surface never carries the forming load. In practice that means: run coated face outward or inward according to the profile and tooling design, keep every roll gap slightly larger than strip thickness plus a small clearance, […]
Read →PPGI Coil for Cold Storage and Food Plant Cladding
For cold storage walls and food processing cladding, the specification that usually works is a prepainted galvanized steel coil with a structural-grade substrate, a regular-spangle or minimized-spangle zinc coating in the range the corrosivity of the room demands, a primer plus topcoat system chosen for the cleaning regime, and a reverse-side coating that can survive […]
Read →PPGI Coil Color Fastness and Chalking After Outdoor Exposure
Will your prepainted galvanized steel roof fade or chalk? Possibly yes — but the rate and severity depend on the paint system, the metallic coating beneath it, the environment, how the sheet is formed and installed, and how it is maintained. You cannot eliminate colour change or chalking by specification alone, but you can specify […]
Read →Salt Spray Hours on PPGI Coil: Why Tests Do Not Equal Years
If a prepainted galvanized (PPGI) coil passes 1,000 hours of neutral salt spray, there is no scientifically valid conversion from that figure to a number of years near the coast. Salt spray hours are a relative, accelerated laboratory ranking of a coating system under one fixed set of conditions; real coastal service life is governed […]
Read →Reading T-Bend and Impact Test Results on PPGI Coil
T-Bend and impact test numbers tell you how far a prepainted galvanized (PPGI) coating can stretch and deform before it cracks, flakes or delaminates — but they only predict survival on your forming line when you compare them with the actual strain, bend radius and shock your line imposes. A “pass” at 2T means little […]
Read →PPGI Coil Zinc Coating Adhesion After Bending and Profiling
If your prepainted galvanized (PPGI) coil cracks or peels after roll forming, the honest answer is that the zinc layer and the paint are rarely “guilty” in isolation — adhesion failure is usually a system interaction between the zinc substrate, the pretreatment layer, the paint film and the forming operation. The zinc coating supplies the […]
Read →PPGI Coil Topcoat and Back Coat Thickness Balance
For most roofing and cladding PPGI coils, the back coat does not need to match the topcoat thickness. A common industry starting point is a topcoat of roughly 18–25 µm and a back coat of roughly 5–10 µm, but the correct balance depends on whether the reverse side is exposed, how the coil is formed, […]
Read →PPGI Coil Primer Type and Thickness: The Layer Buyers Forget
You need to specify primer type and primer thickness separately from the topcoat because the primer is a distinct functional layer with its own chemistry, dry-film thickness (DFT), cure window and adhesion role. A topcoat specification such as “20 µm polyester” says nothing about what sits beneath it. If the primer is the wrong chemistry […]
Read →Polyester vs Polyurethane Binders in Prepainted Galvanized Coil
Yes — the resin binder behind a prepainted galvanized coil can change how long the roof coating lasts, but not on its own. The binder decides how the paint film responds to ultraviolet light, moisture, heat, chemicals and mechanical forming. The substrate, the metallic coating (zinc or zinc-aluminium), pretreatment, primer, pigment, film thickness, exposure environment, […]
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