how to make mould for plaster baby hand cast?

[LookingForwardToSummer]

I want to make a cast of my 3 month old dds hand, but I'm having trouble maki g the mould. Tried playdoh but it stuck to the plaster, even with vaseline layer.

You can buy kits in art shops or aliginate stuff for making mold, it is great but a wee bit pricey.

mould, oops