It never gets that hot here.
We get the occasional 40 - 42 degree day (by this I mean once or twice on a bad year. ) Further west they get lots of 40 - 44 degree days in summer but never get any air temps as high as those which Lu experienced in Iran. That machine spent a lot of its time operating along the coast and closer areas so I doubt the temps it was exposed to were very high or high for very long.
The blades are out in the sun - so on those bad days the actual temp on the blades probably is very high - as high as 175 degrees? I don't know. Maybe, but as far as I know no one has measured it and published the data. Maybe thats a good little project for some engineering student. I suppose putting telatemp strips on the blades would be the easiest way find out.
But I'd be worried about one coming off in flight and unbalancing the blades.
I suspect the high temps would only apply to blades not in flight so you could probably get by without even leaving them on permanently - and having to do track and balances when they were put on. Just have to remember to take them off before starting up.
I guess again the case is - why only two blades suffering - and especially why the blade on a machine that spent most of its time at far lower temperatures down here along the coast. Why not the dozens of machines that permanently live and work in the hot climate?
I still haven't had a chance to ask the owner about which surface debonded. He didn't turn up at the aero club last night. I'll ask him when I see him.