best glue possible for models please

[OhYouBadBadKitten]

dd has been making a model for a school project - cardboard Anderson shelter and rather ambitiously a vegetable garden made out of clay
Shes getting to the point where it all needs to be stuck to the base - Shelter is going on felt and veggies are going onto sandpaper (which is going on to the felt)

Which glue will really really hold it please? (especially as base keeps wanting to curl up.)

PVA will work for clay and carboard and sandpaper. surprisingly strong stuff.
Might show through felt though if you use too much. What about double-sided tape for sticking the felt and PVA for the rest?

ok - will try some pva - thanks