Demystifying the demister

Continuing on from last week's undertakings... 

On the cowl section of the donor cut there was a 6" section that was totally shot along the rolled edge that forms the seam;

 

I flipped the piece over and marked out around the affected steel with a dotted line. This was duly cut out:

 

 

To make a repair piece I used a section from a different part of the donor panel. I had to pie cut the end to accurately recreate the corner curve using the old piece as a pattern;

Repair section was then glued into place:  

...and then ground back as per usual;

I then trimmed up the section to match the profile of the area to be filled;

Out with the old an in with the new; both pieces blasted and ready for fettling and final fitting;