Salt dough footprint - any way to save it?

[Thinkstoomuch]

At nursery they made a footprint of my DS in what I think is salt dough. At first it hardened but it seems to have absorbed moisture from the air and has gone soft. I've tried heating it in the oven (which hardened it again) and then painting it with varnish, but it just absorbed it and started to go soft again. Unless I can do something it's just going to fall apart.
Does anyone know if there's a way to save it?

What a wonderful idea. Sorry I can't help you, but when you find the answer please post it. I'm going to do salt dough casts tomorrow baby feet are sooooooo cute.

Could you pour plaster into it, or PVA or something?

Only thing I can think of is putting it in oven on lowest setting for a few hours (start off with 2 and keep going until it's rock hard. Other than that, plaster of paris. HTH.

Definately back in the oven-not sure what temp though-i made christmas decorations and they went rock hard

Thanks for that great advice. I'll try redoing it in the oven and then maybe a coating of PVA.

Gawd, meant 2 hours btw not gas mark 2

I used to do salt dough models. I always found that a LONG time in the oven at a really low temp would work. When it's rock hard cover it with varnish but NOT a water based one.

make an imprint with clay

If it's going soggy then how about putting it in the freezer before you try to take another cast from it?

It's fun to make a plaster of paris cast, but it might stick to the dough - much better to use something flexible like plasticine.

ELC do modelling clay - you can make an imprint of baby's hand, then make a ring of cardboard to press down into it. Pour in plaster of paris and when it's set you peel off the clay and you're left with a 3d model of your child's hand or foot - nicer than an imprint in my opinion.