Can liquid starch make cardboard really stiff and hard?

Especially thin cardboard? 

i've used wheat paste to glue together cardboard and make a 3D shape for a cat to scratch on. The 50 layers of cardboard made it kind of stiff and hard, but from what I remember of your other question, this wouldn't really apply to your problem

rickharris2 months ago

really stiff NO . + being water based it will make the cardboard soggy.until dry.

You already have the best answers, polyester resin would be the way to go.

steveastrouk2 months ago

Not really hard, like resin hard.

And its susceptible to mould,being great mould food

+1