The complete bodyshell of most cars is built up from a variety of sections which are resistance welded together. This type of weld is more commonly known as a "spot weld" due to its' appearance - a circular weld about 1/4" wide. Each section of a modern car contributes to the strength of the whole shell, so it becomes vital that if any of those sections are removed, a replacement must be welded securely back into position, using a similar number of welds in the same places as the originals, to restore rigidity.
One noticeable trend of the last few years is the move towards larger and fewer panels. An example of this is a normal family saloon body side. Previously the side view (minus doors etc. ) would be built up using sills, roof rails, door pillars and rear quarter, plus other smaller sections where needed. Now a large proportion of vehicles would have this full bodyside produced in one large pressing, so removing a lot of welded joints at one stroke. The downside of this progress is that some panels are available only as large sections, or need to be joined with precision mid-panel.
Obviously different makes and models will have design and detail differences, but the general principles are the same for most cars. Our examples include a simple front wing change, followed by a more ambitious rear quarter\rear wing replacement for those with more courage.
