I never knew how simple it would be to stiffen crochet in a shape.
I must say Terresa Richardson is a great tutor.
It's simple : get a good quality supper glue and pour a little in a bowl. Add quarter of water to it and mix well. Cover your work on the back of any bowl ( the shape you want) and With a help of a soft large paint brush . Apply the paste on your work.
It takes a few days for it to dry. Once dried it can be easily removed from the bowl and use it as you like :)