Sticky solutions

If you’ve had a nasty experience with adhesive, now is the time to put it behind you and investigate what’s new.

Those of us that watched the recent television programme about Thrust SSC thundering up and down various deserts saw the serious punishment that the chassis and structure took. If you were particularly observant you will have noticed that one of the few sponsors logos emblazoned on the mostly black bodywork was that of Permabond.

Permabond makes adhesives, and these were used in a number of applications on the car – initially alongside rivets on the body to stop the panels from buckling and improving stress distribution at the cost of very little weight, an later on small structural parts and sensors.

Different applications across industry require different adhesive products: just on the supersonic Thrust SSC, four were used, and this raises a key point about adhesive use. It is absolutely essential to choose an appropriate product for your application and to prepare the mating surfaces properly.

This may seem obvious enough, but one of the major causes of adhesive failure is inappropriate use and poor preparation (see table).

Adhesives have come on a pac and now there is a bonding agent for practically every application. Modern adhesives are generally packaged in an easy to use format so there is little waste and even preparations that need mixing can be mixed as they are dispensed.

If you’ve been put off in the past, why not take another look. A couple of good guides are Permabond’s Engineering Adhesive Selector and Devcon’s Adhesives for the new Millennium, but most adhesives suppliers will be able to advise you as to the best product for your product or system.

Permabond. Tel: 01703 629628

Devcon. Tel: 01933 675299

{{HOLDING IT TOGETHER

SURFACE SUGGESTED PREPARATION

Metals For good long term performance surfaces should be abraded with emery paper and degreased using a solvent.Plastics Degreasing the surface is usually sufficient. Abrading and degreasing can provide better mechanical strength especially on nylon and acetal. Polyethylene, polypropylene and PTFE cannot be bonded without significant preparation.Rubbers Degreasing the surface. When bonding ‘O’ rings try to obtain a freshly cut surface.Wood Ensure that wood is dry and free from dust and grease. Within certain hardwoods it may be necessary to degrease the surface using a solvent. Always remove all the dust.Composites(eg GRP) Degrease the surface and then abrade with emery paper and degrease again. Ensure all the dust is removed. All the mould release agent must be removed.Glass For general purpose bonding, simply degrease the glass surface using an industrial solvent or a glass cleaner.Stone Roughen the surface with a wire brush. Remove all of the dust.

Taken from Permabond’s Engineering Adhesive Selection.}}