No David, not load bearing, but whatever I graft on will need to be 100% fixed permanently in place, or cracks will eventually show around the edges. I did consider doing that, but using fibreglass. This morning I made all the sections to repair the hole once and for all.......hopefully!
I'm almost sure this thing isn't aluminium now. Seems lighter than aluminium, and it files differently. My welder friend isn't home today, so I never got the definitive diagnosis. Will watch for him tomorrow.
I didn't set anything on fire while cutting the rot away, and was VERY careful I did not put too much heat in one place. When all corrosion was cut away, I was left with quite a hole.
There are 6 separate pieces making the repair patch.
I taped them all together to see what the profile will look like. While it's not exactly original, it will do.
More details in the next posting....