Thicker Section Lap Joints

Where heavy duty plates are required in construction, the use of contouring around the edges can be extremely beneficial. An example of this is the repair of the aluminium superstructures of naval ships. Localised high stresses occur during extreme weather conditions due to differential movement between the hull and the 

A glue line of minimum 0.5 mm is used and the thixotropic adhesive is required to fill gaps up to 3 mm in the vertical or horizontal plane. Attachment of the heavy steel stiffening plate requires a few bolts to carry the load whilst the adhesive is setting. The bolts are set back from the edge of the plate in a low stress area so that the hole and the bolt do not interfere with the function of the stiffener (Fig. 41). 

A very useful example of the benefit of careful design of joint ends can be seen when bonding thin metal to relatively thick epoxy composite. The choice of epoxy 

For many bonding applications, the appearance of the joint is important The adhesive outside the joint improves paformance significantly, but generally detracts from the aesthetic appearance. The following option may be beneficial in achieving a clean joint (Fig. 44). 

When the aluminium carrying the adhesive is placed on the composite, excess adhesive bends back the flap to allow extra adhesive to escape from the joint. Once the aluminium is in position, the flap can be pressed back to the composite surface 

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