LOCTITE Structural Bonding Adhesives

World’s First Fully Bonded Caravan Is Stronger, Lighter and Drier

Henkel and Elddis Team Up to Develop Groundbreaking Process

The UK caravan company Elddis has radically changed its manufacturing methods, favouring a fully bonded structure over one using mechanical fasteners. Out went approximately 800 screws, and in came adhesives for structural and exterior bonding. The outcome has been revolutionary, creating a shell that is stronger, lighter and drier than ever before.

Lightweight and Much More

In recent years, Elddis had sought to cut the weight of its caravans. This would allow customers to use a lighter tow car and add accessories without exceeding weight limits. Another design goal was to eliminate leaks. Elddis’ ultimate goal, however, was the freedom to design products of any size or shape, unhindered by the construction technique.

Elddis had explored various alternatives and decided that using adhesives with current materials was the most compelling option. Henkel’s experience in structural bonding in the aircraft and automotive sectors confirmed the viability of this method and the company was eager to apply this technology in the recreational market. Together, Henkel and Elddis embarked on a three-year development process to create the world’s first fully-bonded caravan.

Seam Welding With Adhesive

LOCTITE UK 1366 B10 was recommended for its ability to withstand the vibration caused by travelling on uneven road surfaces. Initially the panels of a caravan were butt joined with LOCTITE UK 1366 B10; rigorous testing proved its strength. Next, a keyway joint on all mating surfaces was introduced, increasing the bond area by 63%.
The resulting bonded construction is more than 10 times stronger than the original. Flimsy panels are now stiff structural components, so that many of the original timber support structures have become unnecessary, allowing even more weight saving.

27,000 Test Miles

The next step was to road test the bonded caravan design. The fully loaded vehicle completed 27,000 miles (43,500 km), easily meeting the requirements of BS EN1645 Part 1, the master standard for caravan construction.
The bonded structure was then put through tests that mimicked annual rainfall, and also subjected to temperature extremes of -40°C to +50°C. Although no sign of water ingress could be seen, Elddis engineers completely dismantled the structure to confirm that all elements were dry and there were no joint failures. As a result, Elddis has been able to introduce its 10 year bodyshell warranty.

Henkel’s development engineers offer every customer the best possible support in choosing the right structural adhesives for various substrates. Get in touch with us – we’d be happy to help .

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