Testing Epoxy Strength: The High Strength Claims of Selleys’s Araldite Epoxy Glues
(1) Rose Bay Secondary College, Sydney, New South Wales, Austrailia
Epoxy resin is a type of thermosetting polymer that is considered among the best matrix materials with excellent properties including high flexibility, good dielectrics, chemical inertness, and water repellency. The strength of epoxy can be influenced by crosslinked density and the incorporation of a variety of solid particles of butadiene. It is important to understand the techniques used to improve the adhesion strength of the epoxy resin, especially for consumer applications such as repairing car parts, bonding aluminum sheeting, and repairing furniture or applications within the aviation or civil industry. Selleys is a well-known Australian company specializing in cleaning products, adhesives and sealants; their Araldite epoxy makes specific strength claims emphasizing that the load or weight that can be supported by the adhesive is 72 kg/cm2. Our experiment aimed to test the strength claims of Selley’s Araldite Epoxy by gluing two steel adhesion surfaces: a steel tube and bracket. Altogether, a 55 mm surface was used, meaning the load held by the brackets would be 41.25 kg. Loads were added to the bracket as a destructive tensile load test were conducted. To avoid batch effect, three tubes of Selleys’s Araldite epoxy were used. Our results showed that there was a significant difference between actual load and the expected load (41.25 kg) (a two-tailed t-test with p -value < 0.05 with a fracture stress ranging from 0.019 MPa-0.095 MPa, disputing the claim that Selleys’s Araldite epoxy can hold up to 72 kg/cm2 a s we expected the p -value to be > 0.05 in order to accept the claim. The experiment showed that there is a lack of consideration by Selleys for adhesion loss mechanisms and environmental factors when accounting for consumer use of the product leading to disputable claims.
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