Both 8011 and 8079 aluminium foil are widely used as barrier layers in flexible packaging, yet they behave differently in pinhole resistance, surface quality and downstream processing. This guide compares the two alloys on the properties that matter most to converters, explains how thickness and rolling quality affect barrier performance, and outlines a practical way to match the foil to your pack structure, filling method and shelf-life target.
Choosing between 8011 and 8079 aluminium foil for a packaging application is rarely a question of which alloy is better in absolute terms. Both are established barrier materials, and both appear in laminates for food, pharmaceutical and industrial products. The practical answer depends on the packaging structure you are building, the filling and sterilisation route the product will pass through, and the shelf life you need to guarantee. Once those three constraints are clear, the alloy decision usually narrows quickly.
Where the two alloys differ
8011 is an Al-Fe-Si alloy that has been used in packaging for decades. It offers a good balance of strength, formability and cost, and it performs well across a wide range of converting operations. Converters value it for consistent mechanical behaviour during lamination, printing and slitting, and it is a common choice for pharmaceutical blister lidding, closures and general flexible packaging where the foil acts as a functional barrier inside a laminate.
8079 is also an Al-Fe-Si alloy, but its composition is tuned differently, with a lower iron content and a tighter control of trace elements. The result is a foil that is typically softer and more ductile, with a very clean, bright surface. That combination makes 8079 attractive where deep drawing, tight fold radii or a high-quality print and lacquer finish are required, and where the barrier layer must survive severe mechanical deformation without cracking.
Thickness and pinhole control
Barrier performance in aluminium foil is governed less by the alloy label than by the combination of thickness, rolling quality and handling. Pinholes are the dominant failure mode in thin gauges: below roughly 0.009 mm, pinhole count rises sharply and water vapour and oxygen transmission increase accordingly. Both 8011 and 8079 are produced down to very light gauges, but the practical minimum for a reliable barrier depends on the converter's equipment, the web tension in the lamination line, and how much flexing the finished pack will see. Where a demanding moisture barrier is required, specifying a heavier gauge or a double-layer foil is usually more effective than switching alloys.
Matching the foil to the structure
The laminate architecture should drive the alloy choice, not the other way round. A few practical rules of thumb help narrow the options:
- Severe forming or deep drawing: a more ductile foil such as 8079 reduces the risk of tearing and micro-cracks at corners and draw radii, which is why it is often preferred for blister and cup applications.
- General flexible laminates and lidding: 8011 delivers predictable strength and stiffness at an attractive cost, and is well suited to pouches, sachets and closures where the foil is supported by other layers.
- Print and lacquer critical surfaces: a clean, uniform surface with low defect counts matters more than alloy name; ask for surface quality data rather than assuming a grade guarantees printability.
Questions to ask your supplier
Before committing to an alloy, confirm the gauge range and tolerances available, the temper and mechanical properties you can expect, and how pinhole and surface defect levels are measured and reported. Ask how the foil has performed in laminates similar to yours, and request samples at the actual gauge you intend to run so trials reflect production conditions. A supplier who can discuss your structure, filling process and shelf-life target in specific terms will usually help you reach a more reliable decision than a catalogue comparison alone.