FEATURE FASTENINGS & ADHESIVES
HOW TO CHOOSE AN ADHESIVE T
When choosing their adhesive, engineers should avoid making any costly mistakes to avoid bonded surfaces from failing. Here, Peter Crossen, VP of the Maintenance and Partsmaster Innovation Platform at global water, energy and maintenance solutions provider NCH Europe, looks at the considerations to be made when choosing an industrial adhesive
he majority of industrial adhesive jobs can be covered by three main
adhesive categories: Cyanoacrylate adhesives, commonly known as super glues, structural adhesives, and acrylics and anaerobic adhesives. All of these are used to bond surfaces, known as substrates, together. However, these adhesives all have different properties, meaning that engineers must be able to accurately differentiate between them. The main point for choosing an adhesive is to look at the substrates being joined. Of course, the same adhesive will not always have the same effect when joining metals as it will when joining two pieces of wood. The way that the two substrates are joined and the stress on the joint also affects the adhesive that should be used. An angled join increases the bond area and strength between the two substrates, but a thin section of join can be prone to breaking, meaning a stronger adhesive should be used. If the join is also exposed to a lot of tensile or peel forces, a structural adhesive should be used to maintain the strength of the bond. NCH Europe has recently developed super structural technology (SST), which uses nanoparticles to strengthen the bond of metal, standard plastics and composites. Low NRG plastics are traditionally very difficult to bond, so
Cure time should also be considered
engineers should look for adhesives that feature nanoparticles to help them to securely fix these pieces together. The required strength of the bond also impacts the choice of adhesive. Some users must regularly disassemble components as part of the maintenance schedule, meaning that they should choose a lower strength anaerobic adhesive to bond two substrates together. However, using a low strength adhesive on other parts, this could lead to a serious structural failure for a piece of vital equipment, this is because cyanoacrylate adhesives generally have poor peel and impact strength. In such cases, structural adhesives should be used, which have a high level of tensile and peel strength with an excellent resistance to impact.
Careful consideration should be taken when deciding on the best adhesive to bond substrates. Getting it right can reduce time to maintain or increase the life of item
when choosing an adhesive. If a quick fix is needed, a cyanoacrylate should be used, as it takes seconds to cure. If more time is available, then a stronger bond can be achieved with structural adhesives, although they can take up to two hours to cure. In this case, users must decide whether the strength of the adhesive or the speed of the cure time is more important. When choosing an adhesive, how it will be applied is also important. Some products require mixing a base and an activator. However, this can lead to being improperly mixed and subsequently ineffective adhesives. By using a product that can dispense the two parts of the adhesive at the same time through a mixer nozzle, the user can avoid any errors in the formulation. By choosing the right adhesive,
companies can avoid buying large amounts of inventory. Opting for adhesives that can be used on a wide variety of materials ensures that each adhesive is cost effective and can be reused. Careful consideration should be taken when deciding on what is the best adhesive to bond substrates. Getting it right can reduce time to maintain or, increase the life of item.
NCH Europe
www.ncheurope.com
TESA SUPPORTS SUCCESSFUL BRITISH SKELETON TEAM
down on what appears to many to be little more than a high-tech tea tray. The premium acrylic coated cloth tape offers high adhesion and excellent tensile strength and is used on the handles of the special grade mild steel saddle, providing a reliable grip on various surfaces ranging from powder coated polymer, zinc or spray paint finishes.
This year’s season has got off to a great start, with Olympic Champion Lizzy Yarnold kicking things off with bronze in the opening World Cup race in Lake Placid.
tesa has been providing its tesa 4651 tape for many years to optimise the performance of the sleds used by the British Skeleton team. Athletes competing in the skeleton reach speeds of up to 140km per hour and experience G-forces up to 5G whilst lying face
The tape is also used to fasten different types of foam padding on the top of the saddle where the athlete lies. On the bellypan, typically made from carbon fibre sheet or GRP and finished in gel-coat, lacquer or paint, it is used to optimise air flow and speed in general by covering the holes where the runner fits. It also assists in the ‘push’ start, which requires a 20 to 30m sprint before the competitor loads on board.
To enhance the aerodynamics further, most of the British athletes apply the tape along the edges of the sled where the bellypan meets the padding. “Delivering a performance platform to push on from was the mandate for the opening weeks of the season and the last few days delivered that almost perfectly,” says Danny Holdcroft, GB Skeleton’s head of performance. Jeremy Smith, marketing manager for tesa UK, said: “We are proud to know that tesa products play an important part in helping the team to deliver such a sizzling start to the season and we hope it sets and scene for future success.”
tesa
www.tesa.co.uk
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DECEMBER/JANUARY 2018 | DESIGN SOLUTIONS
/ DESIGNSOLUTIONS
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