Paper mache (papier mache) is basically paper and a starch based glue. Although it is an excellent modelling material (easy, safe, cheap) it can be a little weak, so here is how to make papier mache stronger.
Choose a stronger glue
The cheap options of flour or wallpaper paste are fine in many situations, but switching your glue to white PVA doubles the strength of the finished project. However this is costly, so a 50/50 mix of wallpaperpaste and PVA, thinned with water is a great substitute.
Working with papier mache layers
4 layers of newspaper is good, but eight is better. Let the item dry before starting the next layer. The more layers you build up the stronger the finished piece will be.
Additives make stronger, more dureable paper mache
White flour wood glue and joint compound can all be added to make the paper mache stronger.
Think about fibres.
Small pieces of paper randomly applied mean the fibres are all over the place, weaving a strong structure.
However long fibred materials when layered first one way then at right angles are even better. So, consider adding a layer or two of cotton or linen in with your paper. Old jeans are great for making a solid ‘cotton mache’ sculpture.
Resin on paper mache
For a really solid finish an epoxy resin coat will turn a flimsy paper mache object into a rock hard object. Remember to read and follow the rules on ventilation and protective clothing when working with resins.
Laquer for strength
A traditional japanese technique that dates back more than 2000 years, building up layers of laquer is a slow, painstaking technique, but one that yeilds beautiful results.
Fibreglass on paper mache
This is the ‘nuclear’ option, but working with fibreglass is messy and potentially dangerous. However, the finished object will be as solid as can be.