Papier mache is a fun and easy way to create sculptures, models and other objects. Creating papier mache only requires water, flour and old newspaper. Simple shapes are easy to craft from papier mache, but for more complicated projects casting a plaster mould first will give you a solid base for work. With a plaster mould, the forms you can create will be limited only by your imagination.
Create the shape you wish to cast in plaster using plasticine, modelling clay or sculpting foam. Shape your material into the likeness you want your final paper mache casting to look like. The object you sculpt is only limited by the amount of modelling material you have and your own imagination. It may be helpful to sketch out your object first.
Cut the model you have created in half. These two halves will each form their own mould that will be combined later on to once again for the complete sculpture.
Mix your plaster of Paris according to the directions provided on the packaging. Mix enough to cover both sides of the object you have sculpted.
Place the halves of the sculpture model flat-side down into two separate boxes. The boxes should be only slightly larger than the halves of the mould. The closer the fit, the less plaster of Paris you will need to fill the box and create the moulds. Cover the insides of the boxes and the sculpted halves with plastic wrap to allow easy separation from the plaster of Paris when dried.
Pour plaster of Paris into the boxes, covering the moulds completely. Leave these moulds to dry completely.
Separate the plaster of Paris from the models once it has completely dried. If you have applied plastic wrap, the two halves should slide apart easily.
Create your papier mache mixture by combining equal parts flour and water. You will use this mixture to coat strips of newspaper. It will act as a glue holding the strips together, and when dry the newspaper will remain in the shape it has been modelled into.
Line the inside of your plaster casting with plastic wrap to prevent the papier mache from sticking to the mould.
Apply strips of newspaper coated in papier mache mixture to the inside of your mould until it is completely covered. Let the papier mache strips dry thoroughly. Once dried, separate the mould from the papier mache, and you will have a cast likeness of your mould. Combine the halves with a few more papier mache strips, and you are done.
You could also use vaseline or a similar substance to lubricate the inside of your moulds to make separating them easier. This may be a bit messier and will need to be cleaned off properly for your papier mache to fully set.