On Friday, April 19, 2019 at 7:10:14 AM UTC-7, wrote:
I bought a G-103 that had been in a hangar fire in Georgia, Peach State Club. We needed a left wing and the photos showed what looked like a useable left wing on a fuselage with canopies that had been hot enough to melt the canopies. Both canopied draped down like a tarp, but it was the new shape of the plexiglass! The outer skin of the left wing top was blistered and had to be replaced, but the spar caps were undamaged. I figured the wing hadn’t been in 350 degree environment long enough to affect the more dense spar cap. We proof-loaded the wing and it took 5.3 G’s with flying colors! That was some 25 years ago and that ship is still flying today!
Just a little data point about how much heat a fiberglass structure can take,
JJ

There is a reason why fiberglass gliders are painted white: they can't withstand high temperatures. There is a critical temperature called the "glass transition temperature" which is where the plastic starts transitioning from a solid into a liquid. A typical glass transition temp for fiberglass is 100C, well below the temps seen in that hanger fire. The fact that they canopy melted demonstrates that the temp was that high for some period of time..
https://en.wikipedia.org/wiki/Glass_transition