Paper Mache Sculptures Using Positive Moulds

Working with positive moulds can be tricky, but they can be an amazing tool in a paper mache artist’s studio.

What is a Positive Mould?

Moulds allow you to create one or more consistent copies from a given shape. However, positive and negative moulds differ in their form and how material is applied to their surfaces:

• Positive moulds are convex, protruding shapes where your sculpting material is applied to or stretched over the outside surface.
• Negative moulds are concave, hollow depressions where material is pressed or poured into the inside, which allows for finer surface details.

The Paper Mache Dilemma

While negative moulds are great for materials like plaster or resin, paper mache behaves differently. The paper pulp shrinks as the water evaporates and tends to pull away from the inside walls of a negative mould, causing it to detach, warp, and lose its intended shape. Furthermore, the restricted airflow inside a hollow cavity drastically extends drying times, increasing the risk of mould. Positive moulds allow the shrinking paper or pulp to hug the exterior form tightly and dry quickly.

My aim is not to mass-produce identical, factory-perfect duplicates. Instead, I use positive moulds to create consistent basic shapes without the need to build a cardboard or wire armature every single time. Adding details, textures, and character during the final sculpting phase gives me creative control over each individual piece. No two sculptures turn out exactly the same.

Positive moulds can be carved from wood, cast from gypsum plaster, or sculpted from plasticine. In my studio workflow, plasticine (oil-based modelling clay) is the undisputed winner. It doesn’t dry out, remains slightly flexible, and responds to releasing agents. Learn more in my tutorial on Making a Positive Paper Mache Mould Using Plasticine.

Working with Positive Moulds

Materials you’ll need

Before you begin, gather the following supplies:

• A pre-sculpted mould. You can follow my tutorial on Making a Positive Paper Mache Mould Using Plasticine.
• Paper mache clay or pulp. You can use my Paper Mache Clay Recipe using non-toxic, natural, and recycled materials, or use paper strips and cellulose paste.
• Sculpting tools. You can use craft tools or improvise with kitchen utensils like butter knives, spoons, and wooden skewers.
• Releasing agent. I get the best results with talcum powder, but safe kitchen alternatives like cornstarch or Vaseline work as well.
• A knife. You will need a very sharp precision blade to cut the dried shell off the mould.
• Weights. Small pebbles or reclaimed metal nuts to ground your sculpture.

Step-by-Step Guide

Step 1—Crafting the base layer

• Prep the mould. Apply an ample, even layer of talcum powder or cornstarch to the entire surface of your positive mould. This creates a crucial barrier that prevents the wet pulp from bonding to the clay.

• Apply the Pulp. Carefully cover the mould in a uniform layer of paper pulp (roughly 3-5mm thick), or overlay several cross-hatched layers of paper strips. Ensure the coverage is even to avoid weak spots.

• Wait patiently for the paper pulp to dry completely. Depending on your studio’s humidity, this can take anywhere from 24 to 48 hours.
• Release (demoulding). Using a sharp precision knife, carefully slice the dried pulp shell into halves or manageable sections to pull it off the mould. Take your time to ‘wriggle’ the shell free without breaking it.

Step 2—Assembling the base shape

• Add weight. Paper mache sculptures can be lightweight. Glue a pebble, a metal nut, or other weights to the bottom interior of your hollow shell to add stability and prevent the finished sculpture from toppling over.

• Reassemble the shell. Align the cut edges of your paper shell back together. Secure the seams with paper strips and cellulose paste.
• Dry. Let these seams dry completely until the structural shell is rigid.
• Final surface. Cover the entire raw base layer in a thin layer of fine paper pulp. Once dry, use a fine-grit sandpaper to sand the surface, removing unwanted unevenness, seams, or bumps to create a pristine canvas.

Step 3—Adding details and textures

There is no limit to your creative ideas—you can sculpt legs, arms, and ears, or add character with expressive eyes or wings. Do not forget to add internal support like armature wire, toothpicks, or paper to firmly anchor protruding elements to the main body.

Tips for Success

• Allow ample drying time. Always allow time for drying between layers. Rushing risks trapping moisture (and risk mould) or destabilising the structure.
• Release agents. Use generous amounts of talcum powder or cornstarch. It is better to have to brush off extra powder later than to tear your sculpture apart trying to free it.
• Experiment with thickness. Test different thicknesses of paper pulp on scrap pieces first. Thicker applications are stronger but take much longer to dry and shrink more drastically.
• Moisture control. Don’t use too much fluid in your pulp. Your mix should feel like clay or putty, not wet oatmeal.
• Plan for shrinkage. Paper fibres compress as they dry. Expect your final piece to be slightly smaller and tighter than the wet mould size.

Troubleshooting

My dried paper pulp sticks to the mould or breaks into pieces during removal

This is a common issue and usually comes down to three main culprits:

• Timing. You might have waited either too long or not long enough to dry your pulp on the mould. The paper mache needs to be dry enough to hold its shape firmly, but you will need to catch it before it turns stone-dry to preserve the flexibility needed to wriggle it off more complex curves.
• Insufficient barrier. You may not have applied enough talcum powder or releasing agent. Ensure 100% of the mould is covered
• Adhesive overload: You might have used too much glue or adhesive in your paper pulp mix. An overly sticky mixture will bypass the powder barrier and glue itself permanently to the mould as it dries. Try reducing the cellulose paste ratio or add more sawdust.

What’s Next?

Once you are happy with your shape and surface, it is time to seal your sculpture, paint it, and finally varnish it. More about that soon-ish.

Thank you for reading! If you enjoyed this step-by-step guide, you might want to check out my other tutorials.