I have been mulling this for a few weeks with no result so I now approach the experts...
My fuel bay is ply sheathed in glass which was badly delaminated. It appears a single pack primer was used under the glass which probably did not help. I have cut back the rotted section to get a scale of the problem but I am lost on the best solution.
My thoughts on options;
1) construct a full 12:1 scarf in a a new piece
2) clean up edges and butt in a new piece with a block behind.
3) clean up edges and butt in a new piece
I have started constructing a patch a few times but I am not sure my skills are up to it. Scarfing on a workbench is one thing but in situ like this is causing me some problems. I have tried a few practice pieces and the results are pretty rough and ready.
Obviously I want a fairly strong result as the bay will have 80kg of fuel bouncing around.
Any input? are options 2 or 3 that inferior? methods of doing a decent scarf in place?