news — from the mill.
Production notes, industry updates, and a little colour on what we’re making this month.
PPGI Coil for Cold Room and Insulated Panel Facings
Standard PPGI coil can be suitable for cold storage and insulated panel facings, but only when the coating system, substrate and surface finish are specified for the actual environment. A generic “polyester PPGI” sold for general roofing is often not the right choice for a frozen-store wall or ceiling panel. The buyer question is therefore […]
Read →PPGI Coil for Agricultural and Livestock Building Cladding
For poultry or livestock sheds with constant ammonia and moisture, the PPGI coil specification that usually works best is a galvanized substrate with a heavier zinc coating, a primer plus topcoat system selected for chemical and humidity resistance, and a back coating — not bare or thin wash-coated reverse — plus fixings and laps detailed […]
Read →PPGI Coil Gloss Measurement: Method and Specification
Gloss on PPGI coil is measured with a gloss meter at a defined geometry — most commonly 60 degrees — after the instrument is calibrated against a certified reference tile, and the reading is expressed in gloss units (GU) against that standard. To answer your order question directly: write a nominal gloss target, a measurement […]
Read →PPGI Coil Coating Adhesion Failure: Causes and Prevention
Paint peels or flakes from prepainted galvanized coil when the adhesive bond between the paint system and the metallic substrate is weaker than the stresses applied to it. In practice, that weakness usually traces to one of five root causes: inadequate or unbalanced pretreatment chemistry, an out-of-window curing schedule, contamination on the galvanized surface, an […]
Read →PPGI Coil Thickness Tolerance and Roll Forming
As a working rule, most roll formers should treat any thickness variation beyond roughly half of the forming clearance as a potential problem, and agree a tighter band with the mill than the general standard allows. In practice, a common starting point for light-gauge PPGI is a nominal thickness tolerance of about ±0.02 mm to […]
Read →GI Substrate Spangle and Surface Quality in PPGI Paint
Yes. The galvanized substrate can affect both the final look and the adhesion of your PPGI coil. Spangle, surface roughness, zinc-coating uniformity, residual oil, oxidation and handling marks on the GI coil can print through or interfere with the paint system. The effect is not automatic: it depends on paint thickness, pretreatment, primer choice, spangle […]
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PPGL Coil Paint Adhesion: Why Galvalume Is Harder Than PPGI
Paint adhesion on PPGL coil is generally harder to control than on PPGI coil because the galvalume (55% Al-Zn) surface is chemically less reactive, more prone to forming passive oxide films, and more sensitive to surface contamination and pretreatment chemistry than a conventional zinc coating. On PPGI, the zinc surface reacts readily with cleaning and […]
Read →PPGI vs PPGL vs Galvalume for Roofing: Climate and Budget
If you are choosing between PPGI, PPGL and galvalume roofing, start with the environment the roof will live in, then set your budget. PPGI (prepainted galvanized) is a zinc-coated steel with paint on top; PPGL is prepainted galvalume, so its metallic layer is aluminium-zinc rather than zinc; galvalume (unpainted Al-Zn coated steel) is the bare […]
Read →PPGI Coil Supplier Audit: Questions That Reveal Real Capability
To confirm a PPGI coil supplier can actually meet your specification, audit the coating line rather than the brochure: ask for the line configuration and curing method, the written coating build-up (primer and topcoat dry film thickness by side), substrate and metallic coating evidence, in-process thickness and cure controls, and traceable test reports tied to […]
Read →Reading a PPGI Coil Warranty: Paint and Corrosion Coverage
A PPGI coil warranty should define, in measurable terms, which paint properties and which corrosion outcomes the supplier or coating producer will stand behind, for how long, under what exposure conditions, and what the buyer must do to keep the coverage valid. In practice, most disputes arise less from the headline duration than from the […]
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