How much water do I add to the plaster powder?

[snufflepuss]

I have a "make your own fridge magnet" kit which includes two 124g packs of plaster powder which I am told to mix with an "appropriate amount of water" but how much water is that - the instructions do not say ? You then pour the plaster into moulds and allow to set, paint and glue on a magnet.

Can anyone advise on how much water to mix it with?

many thanks

Add it slowly til you get a thick pouring consistency (thick cream?) I guess. You can always add more water but you can't take it out