Papier-mâché

Ideas and projects using papier-mâché.

  • Papier-mâché clay

    I was looking at some compounds our lab is throwing out, saw calcium chloride and sodium sulfate, and figured those react to make gypsum. This brought me back to an old papier-mâché clay project idea I had.

    Goals:

    • Create 3D forms, e.g. fake tree bark / branches
    • Somewhat fireproof
    • Somewhat strong

    Traditionally papier-mâché clay uses PVA glue, drywall joint compound (mostly gypsum) and paper to make a paste that can be shaped like regular papier-mâché but becomes much harder and stronger. I think I didn’t continue with the project before because the PVA glue got prohibitively expensive for larger projects. Now I’ve found some projects using cheaper glue, e.g. from flour/cornstarch or cooked flour. Here‘s another even simpler recipe with just flour, drywall compound and paper fibre.

    Actually the first recipe is already all I need. I could add some pigment powder (e.g. iron oxide) to the mix to make it browner, so it requires less painting. This should work (video). Painting: perhaps only some darker paint in the ridges, I think using the technique in this video.

    If my lab is really discarding so much calcium chloride and sodium sulfate, maybe I could make my own gypsum. However, gypsum is cheap, so it’s probably not worth it. In the interest of finishing the project, I guess I should buy drywall joint compound (snelgips). If it sets too fast, I could add a bit of citric acid (maybe 1-2% of gypsum weight) to slow the setting time.

    I could use the potato starch that my lab is throwing out (expired 15 years ago), but again, starch is cheap – corn starch is like €3 per kg.

    I’ll need:

    • Papier-mâché clay ingredients
      • Flour
      • Cornstarch
      • Gypsum
      • Paper or cardboard – pressed cardboard apparently works well, I could save some from the lab
    • Aluminium foil
    • For small batches:
      • Bowls
      • Second hand hand mixer
      • Base/armature out of cardboard
    • For larger batches:
      • Buckets (have)
      • Paint mixer on electric drill (have)
      • Base/armature out of PVC or wood

    I could even make a tree sculpture out of the large 20cm diameter pipe that I have. Perhaps something like this. These much smaller sculptures are also very nice.

    First I should make a small test batch, and also check if it is indeed fireproof!

    Here‘s a recipe with just powdered joint compound and gossamer fabric instead of paper. It’s not really papier-mâché clay any more since there is no cellulose fibre, however it looks even easier, lighter, quicker to use. Hmm. Gossamer fabric is cheap (€1-2 per m, 1.4m wide),

    To be continued.