Plastic and glass work on the modern bodywork

A modern body consists of more than metal. Bumpers panels wheel arch linings and many details are plastic and the windows are part of the car's overall strength and safety. The body technician must therefore be able to assess when a plastic part can be repaired and when it must be replaced — and know the requirements for installing windows.

Plastic is used because it is light, formable and rust-free. However, different types of plastic behave very differently: some can be glued and heat-welded, others tolerate neither. Knowing the plastic type is therefore the first step before deciding whether a crack can be repaired or the part must be replaced.

A minor crack or deformation in a plastic bumper can often be repaired by plastic welding or gluing and subsequent buildup and painting where appropriate. However if the damage is large or is in a place with significance for safety or fit it argues for replacement. The assessment is about both durability appearance and economy — and always about what the manufacturer recommends.

Conditions when working with plastic

• 01Determine plastic type before choosing method — not all plastics can be welded or glued.
• 02Clean and pre-treat the surface so repair and paint adhere.
• 03Use appropriate primer on plastic so the varnish doesn't peel off.
• 04Be aware that plastic works with temperature.
• 05Follow the manufacturer's guidance on materials and curing times.

The windscreen is not just for seeing through. A glued windscreen contributes to the chassis stiffness and can be important for the airbag to deploy correctly and for the roof not to give way in a rollover. That is why correct windscreen replacement is safety work where glue pre-treatment and curing time must be followed carefully.

Plastic and window work is often what the customer notices first because it sits visible and must fit precisely. A bumper that lines up and a window without leaks shows that the entire repair has been done with care. The skilled craftsmanship in the small reflects the quality of the large.