this sort of thing

I can see a couple of small repairs/inventive mods that would benefit from a glue that can be applied, with copious amounts of time to set up and curing in seconds to rock hard. The specs arm I broke ie.
And if it is a gap filling glue it might serve as the lug (say) that is needed. And maybe if it can be semi hard and carved then fully set - wow! Maybe built up in two goes.

I am assuming it is not hygroscopic like super glue, would I be right?

Advice please. TIA