Many manufacturing defects can lie dormant in a frame, holding together under normal riding loads. When a crash occurs however, forces are exerted on the frame from different directions than intended, and the fault isn't able to hold up.
This Giant Liv Avail is a good example of how this can happen; a crease in the lay up - running diagonally across the tube - just couldn't stay together when involved in a crash.
To begin with we completely removed the fault, enabling us to scarf into the good material, providing a solid interface for our repair.
The final photo shows the paintwork restored which includes some tricky airbrush work.