I have couple of MTH F3 Frames that have fallen apart and I have been unsuccessful finding replacement frames even from MTH. I have started to design a frame that can be 3D Printed. So far it looks like it may be possible. I have completed the first part which is the main frame component. I plan to create a separate part for the fuel tank that can snapped on to the main frame. I still have work to do on the piece in the photo.
I thought I would share this as a possible alternative.
Idea-thinker