PEEL

Introduction to Peel Rivets

Peel rivets, also known as "star" rivets or peel-type blind fasteners, are specialized mechanical joints designed specifically for fastening soft, brittle, or porous materials. Unlike standard blind rivets that compress into a tight, localized bulge on the blind side, peel rivets feature a unique mechanical expansion mechanism. During installation, the mandrel retracts and cuts into the rivet body, causing it to bifurcate into multiple "petals" or legs that peel back against the blind side of the material. This multi-leg expansion creates a vastly larger bearing surface, which evenly distributes clamping forces and significantly reduces the risk of pull-through or substrate distortion. While they offer slightly lower tensile strength compared to conventional structural rivets, their ability to prevent damage to delicate substrates makes them an essential component in specialized assemblies.

Materials and Available Finishes

Given their primary function of joining delicate or easily deformable materials, peel rivets are engineered from specific alloys that provide the necessary ductility to split evenly without fracturing.

The primary materials used in their construction include:

• Aluminum: The most common material for the rivet body, as its inherent ductility allows for smooth, reliable peeling into petals. Aluminum also offers excellent natural corrosion resistance.
• Steel: Typically used for the internal mandrel to ensure it possesses sufficient hardness and tensile strength to decisively split the aluminum body during installation. In some heavier-duty applications, the entire rivet body may also be formed from specialized steel alloys.

To enhance aesthetic compatibility and environmental resistance, these fasteners can be treated with a variety of surface finishes, including standard Polished aluminum, Zinc Plated (for steel components), and Painted variations to match exterior trim or roofing materials.

Technical Mechanisms and Properties

The defining technical feature of the peel rivet is its load-spreading mechanism. Upon the application of force by a standard riveting tool, the body predictably splits—most commonly into four distinct legs or petals.

This mechanism provides several engineering advantages:

• Large Bearing Area: The broad footprint on the blind side acts similarly to a large flat washer, making it ideal for distributing clamp load.
• Hole Versatility: The expansive action is highly effective at filling oversized, irregular, or misaligned holes where previous fasteners may have failed.
• Tensile Properties: Engineers must account for the fact that peel rivets generally exhibit lower ultimate tensile and shear strengths than solid or standard blind rivets, trading maximum load capacity for substrate protection.

Applications and Substrate Suitabilities

Peel rivets are engineered specifically for applications where traditional fastening methods would crush, crack, or pull through the base materials.

They are highly suitable for joining:

• Soft Materials: Including rubber, felt, and cardboard.
• Plastics and Fiberglass: Preventing cracking in automotive composite panels, RV bodies, and boat interiors.
• Wood: Fastening plywood or timber panelling in mobile home construction and cabinetry.
• Brittle Materials: Attaching insulation and soft fascia without fracturing the substrate.

They are frequently specified in the construction, automotive, and roofing industries, particularly for fastening lightweight insulation or securing assemblies where the backing material lacks structural density.

Conclusion

Peel rivets offer a highly specialized and effective solution for joining delicate, porous, or highly compressible materials. By sacrificing raw tensile strength for a highly effective, load-spreading petal mechanism, they ensure that soft and brittle substrates can be permanently and securely fastened without the risk of structural damage or pull-through failure.