I invented this method a couple years ago to fix the small, thin, delicate landing gear of a 1/72 airplane. It worked great and I always thought it would work well to fix bent or broken car model A-frames or window frames. Got a chance to fix a car this way last week and it worked as advertised. If you don't have any balsa model airplane tissue laying around, or don't know anyone who does, the kind of tissue used in gift packaging or sometimes for gift wrapping will work fine, as long as it's thin, flat, porous, and has a little stiffness to it (i.e., Kleenex won't work).
These links show the fix in progress, and the finished result.
https://www.tapatalk.com/groups/hyperscale/viewtopic.php?f=578046&t=474182&p=1839420
https://www.tapatalk.com/groups/hyperscale/viewtopic.php?f=578046&t=474278&p=1849007