Pastes and Pulp
Paper Mache Paste
There's a world beyond white glue when it comes to paper mache. Everyone has their own theory of what works best. I'll let you decide for yourself.
Methyl Cellulose (MC)
Without getting too technical, Carboxymethylcellulose (CMC) and Methyl Cellulose (MC) is a plant-derived substance that comes in powdered form. David Clemens, an artist, describes it as such:
"Methylcellulose (MC) is a chemically processed starch of cellulose ethers made from plant fiber, usually wood or cotton. The powder gels into a viscous liquid in water to make a weak glue and resilient film almost like thin plastic. There is another variety of it called sodium carboxymethylcellulose (CMC) which has a stronger adhesive property, but the sodium makes it slightly more crystalline, and MC dissolves more easily in water (smoother.) It's less prone to mold than animal glues and other starches, has virtually no shrinkage when it dries, and will not spoil.
It can be found in soft pastels and chalks as a binder to hold the pigment together, or used for sizing paper, and in making wallpaper paste. It is completely non-toxic, and can also be processed as a food additive and candy glaze. Ceramists use CMC to help harden the glaze on pottery."
If you are mixing your own batch at home, it can be quite a challenging process.
David Osborne wrote a great article explaining what it is and how you should mix it if you're ever able to get your hands on it (once you've followed the link, scroll halfway down the page).
FYI - Elmer's Art Paste is apparently made with CMC.
Wallpaper paste tends to be a popular choice. It is made with some form of CMC and often has a fungicide added to it which deters mould growth.
It should be noted that I have never had a problem with mould and my props. As long as you allow the layers of mache to dry completely, and use a latex paint (regular indoor paint) as a base coat, the chance of mould is very low. The exception being if you put the prop outside without weather proofing it, or you use flour in your pastes.
Tapioca, Cornstarch, All Purpose Flour. These are ingredients I've seen in paste recipes across the web. Some people don't like to use it, claiming it encourages insects and vermin to snack on your creation. Others steer clear of it because it's food and food promotes mould. This would explain why many flour-based recipes include salt and/or bleach (to ward off mildew).
I've gone digging around the Internet for reliable sources, and decided who better to trust than a fellow haunter. DeadSpider shares this favourite recipe on her website:
1 c. Flour
1 c. Corn Starch
1 tbsp Salt (to deter mold)
1 1/2 c. Water
1 c. White Glue
Combine dry ingredients. Add water and mix thoroughly. Add glue stirring to combine.
Paper Mache Pulp
There is a basic method to make a mixture of clay-like papier mache to sculpt with. That's the straight forward part of this next section since most people agree on the overall process. The tricky part is the conflicting details specific to some of the steps.
The most common approach:
- Tear up newspaper into strips (some people suggest using a paper shredder. My only concern with this is that you don't get the loose fibres that you would by tearing, but it may not make a difference since the rest of the process involves breaking it down even more).
- Soak newspaper in water overnight.
- Drain and boil the paper in clean water (some say for 30 minutes, some say an hour, some say 3 hours. Basically you're waiting until the fibres start to break down in the paper).
- Beat/whisk the pulp to break down fibres (some say to use a blender - one that you never intend to use for food again - while others say to use a drill with a paint mixer attachment).
- Strain the pulp mash (using a fine screen of some sort). NOTE: After this stage, some people add it directly to their paste mixture to make their clay while others use step 6
- Spread it out and let dry.
You can store the dried pulp in a plastic bag until it is ready to be used. Depending on the desired texture for your project, you may wish to grind it down again (using a coffee grinder) before mixing the paste of your choice into the pulp until it forms a clay-like consistency.
Some people add chalk, flour, salt and/or linseed oil to their pulp mixtures. As an example, look at Martin Favreau's collection of recipes in an article about Finishing Paper Mache (porcelain finish), Hard Mache (for strong pieces), and Egg Carton Mache.
Or, you could simply skip all this pulp nonsense and choose to buy Celluclay and/or Paperclay.