I cut the fairing so the edges of the hole were straight, makes it easy to fit a filler part in there
I heated this square until it was flexiblethen clamped it to the fairing and waited for it to cool. Once it was cool I heated up the right edge to form the 2nd curve and the corner. Once that was done I marked from the inside of the fairing where to cut
This is the final filler piece ready to get melted in. I cut it too big by a fe MM on each edge and hand sanded/filed it to fit. it has to fit very tight or the joints will fatigue and crack over time.
First pass with teh plastic welder, came out good, but it looks like shite
Ok, that looks better, was sanded using my home made 1x3" block sander
There are still some divets and low points where the heat distorted the plastic, which requires some bondo. I try to get the plastic as flush first before going to bondo. I also do my best to use as little bondo as I possibly can.
And finally the finished repair, sanded from 60 to 1000 grit paper, the surface feels like an egg shell, and is ready for paint, or in my case vynil
Total 'actual' work time is just under 5 hours. I probably put another 5 or 6 into it waiting for the plastic to cool so I could keep going without melting the plastic until it droops or distorts beyond repair.