[grandad]

I dont know if this will be of any use to anyone, (or if someone has already said) but, has anyone tried the superfast SUPER glue and bicarbonate of soda method of filling a gap with HUGE strength? just experiment with it. a very short working time , it hardens rapidly, it can be sanded and is easily as hard as bone, have used it to form a new guitar bridge so SUPER tough and very smooth. use a metal fingernail file for smooth as silk finish.
WARNING dont let it touch your skin. and DO experiment first .. that is essential.. you will see why. FAST.
also btw try soaking white toilet tissue and blending it after a few hours squeeze out the excess water , add elmers glue and some cornflour about 33% of each ... more paper for thicker mix... you can model this for example curved tiny struts on biplane etc. or use as a filler .. sandable when dry