Structural epoxy resin (adhesive)

Physical properties

Laser processing

Thermal decomposition releases gaseous Bisphenol A and toxic amine vapours. Not laser-processable by nature and form.

CO₂: Not applicable. Bonding material, not available as laser-processable sheets or panels. Thermal decomposition generates toxic smoke with gaseous BPA.

Diode: Not applicable.

Fiber: Not applicable.

CNC / milling processing

Bonding material applied in a thin layer between substrates. Not available in a machinable bulk form. Once cured, the adhesive joint is not individually accessible for CNC machining.

Post-processing

Sanding: The joint cures fully to a hardness suitable for sanding (80–120 grit) to remove edge flash. The rigidity of the cured adhesive makes it workable like the material it bonds.

Gluing: Specifically designed for structural bonding between difficult substrates: metal-to-metal, metal-to-wood, metal-to-composite, ceramic-to-metal. Surface preparation is critical: degreasing with acetone, mechanical abrasion 80–120 grit, optional epoxy primer for porous substrates. Typical shear strength: 15–25 MPa on steel-to-steel.

Over time: Excellent long-term durability on properly prepared joints. Resistance to fatigue, moisture, and common solvents. Limited flexibility: on joints subject to intense vibration, prefer elastic formulations (rubber-toughened epoxy). May become brittle at temperatures below −10 °C.

Common defects

• Insufficient cure from non-homogeneous mixing — always respect the manufacturer's weight ratio
• Insufficient adhesion on unprepared or oil-, grease- or oxidation-contaminated surfaces
• Minimal but present wet shrinkage — not suitable for applications requiring precision to 0.01mm
• High exotherm for quantities exceeding 100g mixed in a container — spread immediately onto the joint

Safety

Recommended PPE: gloves_nitrile, eye_protection, mask_a1

The liquid components are irritating to skin and the respiratory tract. The amine hardener can cause permanent skin sensitization with repeated exposure. Nitrile gloves, protective eyewear, and adequate ventilation during application. Do not heat the product to accelerate curing without knowing its flash point.

Availability and formats

Commercial formats: 1:1 or 2:1 two-part cartridges in 50ml, 200ml, 400ml, A+B kit in separate jars from 250g to 5kg, fast formulations (5–15 min open time) and slow formulations (30–90 min open time)

Related materials

Sources

• Huntsman Araldite — 2011 Structural Adhesive Technical Data Sheet
• Loctite EA 3430 Technical Data Sheet
• Henkel — Structural Bonding Manual