Foam and sandwich core materials are generally used as core structural materials for composite laminates, delivering added strength, stiffness, and insulation, without adding weight. Our vinyl foam sheets are easy to handle, readily conform to shapes, and can be bonded in layers to add thickness. Whereas our polyisocyanurate mix and pour foams are perfect for filling cavities, flotation, and sculpting and are available in 2lb and 6lb densities. Finally, our sandwich core materials are ideal for building lightweight structural layers with even greater strength-to-weight ratios.

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Foam and Sandwich Core including End-Grain Balsa can be found in infrastructure applications, wind energy, land transport, and throughout the marine industry.

At, look for foam in one of several categories:

  • Mix-and-pour polyurethane foam--Once mixed equally, this foam expands rapidly to fill any sized cavity; best suited for flotation, sculpting, and for structural support.
  • Vinyl foam--All selections are quality DIAB Divinycell brand; sold by the sheet and used chiefly as sandwich core material.
  • Divinymat--Engineered to be both a sandwich core and a flow media for resin infusion; Divinycell foam sheet scored and held together with light scrim backing.
  • Polyisocyanurate foam--Most frequently used for mold-less pattern making; sold by the sheet and in a 4' x 6' block.

Foam and sandwich cores are commonly used in composite materials to enhance their structural properties, reduce weight, and improve overall performance. Let's explore their roles and benefits in composites.

  1. Mix and pour foam, also known as pour-in-place foam, is a type of foam material that is commonly used in composites for various applications. It is a two-component system consisting of a liquid resin and a catalyst or hardener. When these components are mixed together, a chemical reaction occurs, resulting in the expansion and curing of the foam. Here are some common uses of mix and pour foam in composites:
    • Core Material: Mix and pour foam can be used as a core material in sandwich structures. It is poured or injected between two face sheets (such as fiberglass or carbon fiber) and allowed to expand and cure. This creates a lightweight, rigid core that enhances the stiffness and strength of the composite panel.
    • Void Filling: Mix and pour foam is often used to fill voids or cavities within composite structures. It can be poured into spaces or gaps where additional support, buoyancy, or insulation is required. The foam expands to fill the void and adheres to the surrounding composite, providing structural integrity and reducing weight.
    • Mold Making: Mix and pour foam can be used to create molds for composite parts. It is poured into a mold cavity, allowed to expand and cure, and then used as a lightweight and easily machinable mold for fabricating composite components.
    • Repair and Modification: Mix and pour foam is also used in composite repair and modification applications. It can be used to fill damaged or voided areas, restore structural integrity, or add additional features to existing composite structures.
    • It is important to note that the specific properties and characteristics of mix and pour foam can vary depending on the formulation and manufacturer. Therefore, it is essential to select a foam system suitable for the intended application and compatible with the other materials used in the composite structure.
  2. Foam Core: Foam cores are lightweight materials that provide excellent strength-to-weight ratio and energy absorption capabilities. They are typically made of polymers such as polyurethane, polystyrene, or polyvinyl chloride (PVC). Foam cores are available in various densities, allowing engineers to choose the appropriate core material based on the specific application requirements.
  3. Benefits of foam cores in composites include:
    • Weight reduction: Foam cores have low density, contributing to the overall weight reduction of the composite structure.
    • Enhanced stiffness: The presence of a foam core increases the stiffness and rigidity of the composite, improving its resistance to bending and deformation.
    • Improved impact resistance: Foam cores are effective at absorbing and dissipating energy upon impact, making composites more resistant to damage from external forces.
    • Thermal insulation: Some foam cores provide thermal insulation properties, which can be advantageous in applications where temperature control is important.
  4. Foam cores are commonly used in industries such as aerospace, marine, automotive, and construction for applications such as sandwich panels, boat hulls, aircraft interiors, and wind turbine blades.
  5. Sandwich Core: Sandwich structures consist of two thin and stiff face sheets (often made of fiber-reinforced composites like carbon fiber or fiberglass) bonded to a lightweight core material, creating a sandwich-like configuration. The core material can be foam, honeycomb, or balsa wood.
  6. Benefits of sandwich cores in composites include:
    • High stiffness-to-weight ratio: Sandwich structures offer exceptional stiffness while maintaining low weight, allowing for efficient load distribution and improved structural integrity.
    • Increased bending and torsional stiffness: The core material in a sandwich structure provides resistance against bending and torsional forces, enhancing the overall stiffness of the composite.
    • Impact resistance: Sandwich structures with specific core materials, such as honeycomb, can effectively absorb and distribute impact energy, providing improved resistance to damage.
    • Thermal insulation: Certain core materials offer thermal insulation properties, making sandwich structures suitable for applications requiring temperature control or insulation.
  7. Sandwich cores find applications in a wide range of industries, including aerospace, marine, automotive, wind energy, and construction. They are used in components such as aircraft panels, boat decks, automotive body panels, and wind turbine blades.

Overall, foam and sandwich cores play crucial roles in composite materials, providing lightweight solutions with enhanced mechanical properties, improved impact resistance, and other desirable characteristics for various applications.

See how foam matches up to other materials in our Sandwich Core category when you visit our Learning Center and read, Guidelines for Sandwich Core Materials, or when you view An Introduction to Sandwich Core Materials on the Fibre Glast Blog.

You can place your order on our website or, if you have any questions, call 1.800.838.8984 | 8 a.m. - 5 p.m. EST Mon-Fri.

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