13. Brazing, soldering, glass fibre and body filler

Non-metallic vehicle structure

17. Repairs to plastics

15. Plastic and Fibreglass

These are bonding processes and are not regarded as strong enough for repairs to load bearing members  although they are normally adequate for other repair work.

Brazing, bonding and riveting are only acceptable where used by the vehicle manufacturer and the standard of and such repair must be comparable to the original.

Plastics are becoming more common in vehicle structures.  Glass reinforced plastic (GRP - also known as Fibrelass)  is the most common, and variations include bodies with metal chassis or subframes and plastic monocoque (chassis-less) construction.

- Within a 'prescribed area', or

- Which affect the load bearing structure should be as strong as the original part.

14. Identifying types of repair

16. Testable items mounted to plastic structures

18. Structural integrity and the removal or substitution of metal panels

It is sometimes difficult to distinguish between welding and brazing after the repair has been covered in paint or underseal.  However, brazing may be detected by the smooth fillet of filler or a gold coloration at the edge of a joint.

Glass fibre,  body filler, aluminium etc may often be detected by a difference

- In appearance, or

- In sound when tapped, or

- By the use of a magnet

Testable items, such as steering racks, sub-frames and seat belts, are sometimes mounted directly to plastic structures which do not have metal reinforcement.

Although usually designed to support these components, some are not, particularly self  build kits.

Non-metallic structures must be assessed on their merits.  Look for evidence of weakness.  Cracks, separation or delamination within a 'prescribed area' or a component flexing on its mounting to the extent that it is clear that it is likely to work loose or break away are reasons for rejection.

On a vehicle of integral construction the strength and stiffness of the whole structure may be seriously effected by any panel being removed or replaced by a panel of different material.

In considering whether the original strength and stiffness has been significantly reduced following a modification, the tester must consider whether he/she is qualified to make this assessment.

If the tester decides that the modification renders the vehicle unsafe, he/she must issue a 'Notification of Refusal' within Inspection Manual item 6.1 Reason for Refection 1.

It is unacceptable for plastics to replace or reinforce corroded or weak metal in "prescribed areas" or load bearing members or components.

Issue Date: 10th January 2005