news — from the mill.
Production notes, industry updates, and a little colour on what we’re making this month.
PPGI Coil Storage and Handling After Delivery
There is no universal shelf life for PPGI coil. In practice, a prepainted galvanized coil can be stored for weeks or many months before fabrication, but the safe interval depends on the coil’s substrate, metallic coating mass, paint system, edge condition, packaging, and — above all — the storage environment. A dry, ventilated, condensation-free warehouse […]
Read →Galvanized Steel Surface Treatment Before Painting
Galvanized steel needs, at minimum, an alkaline or neutral degrease followed by a rinse, and in most coil-coating specifications a chemical conversion coating (typically chrome-free passivation or a thin phosphate) before primer and topcoat. On a continuous coil coating line these steps run in sequence: clean, rinse, convert, rinse, dry, prime, cure, topcoat, cure. The […]
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PPGL Coil Corrosion Performance in High Heat
For a roof in a very hot climate, PPGL (prepainted aluminum-zinc coated steel) is usually the better starting point than PPGI (prepainted zinc coated steel), because the aluminum-rich metallic coating behind the paint forms a thin, stable aluminum oxide film that resists high-temperature oxidation far better than zinc alone. PPGI relies mainly on zinc, which […]
Read →PPGL Coil Specification and Application Guide
An AZ150 PPGL coil specification means the steel carries a hot-dip aluminium-zinc metallic coating with a nominal coating mass of 150 g/m² total (both surfaces combined, measured as the triple-spot average), and that this coated substrate has then been painted. The “AZ150” tells you about corrosion protection from the metallic layer; the “PPGL” tells you […]
Read →PPGI Versus PPGL for Roofing and Cladding
If your project is a normal roof or wall in a mild-to-moderate environment, PPGI (prepainted galvanized, zinc-coated) is usually the lower-cost choice and performs well when the paint system and substrate thickness are correctly specified. Choose PPGL (prepainted galvalume, aluminium-zinc-coated) when you need better resistance at cut edges, in coastal or high-humidity air, at elevated […]
Read →PPGI Coil Packaging and Shipping Damage Prevention
To avoid rust and edge damage during sea freight, PPGI coils should be packed as a sealed moisture barrier around a rigid, edge-protected coil: a dry, clean coil; inner and outer wraps that resist tearing and water vapour; steel or heavy-duty edge protectors on both the inner and outer rims; a rigid eye or wall […]
Read →PPGI Coil for High-UV Desert Climates
Will your PPGI roof fade quickly in strong sunlight? It depends almost entirely on the paint system you specify. In high-UV desert climates, standard polyester coatings are the most common cause of premature colour change and chalking, while PVDF (polyvinylidene fluoride) and HDP (high-durability polyester) systems are generally formulated to hold colour and gloss far […]
Read →PPGI Gloss Level Specification for Roofing and Cladding
For most architectural roofing and wall cladding, specify a matte to semi-gloss PPGI finish — typically a 60° gloss reading in the range of about 20–40 units — unless the project design intent, the paint system supplier’s data sheet, or the contract specification requires something else. High-gloss (often above roughly 60 units at 60°) is […]
Read →PPGI Coil Color Matching and Delta E Tolerance
To make sure your second PPGI coil order matches the first delivery, you must control three things before production starts: a retained physical colour standard, a written Delta E tolerance with a stated measurement method, and a documented paint system (resin, pigment chemistry, primer and topcoat) that the supplier agrees not to change without your […]
Read →GI Substrate Quality and PPGI Coating Performance
Yes — a poor galvanized substrate can cause prepainted coil to blister or peel even when the paint system itself is sound. Paint adheres to the zinc surface, not to the steel beneath it, so anything that weakens the zinc-to-paint interface will eventually show up as a coating defect. The most common causes are inadequate […]
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