Two Ingredient Casting Mold
- Maizena or cornstarch
The Other Stuff
- Whatever you want to mold. I used my shapely pear 😉
- Plastic knife for mixing
- Mixing container
- Caulking gun
- Sharp knife
- Super Glue
Prepping the Form for Molding
Wash and dry the pear, or whatever you decide to cast. Since I’ll be filling the mold with concrete once it’s dry, I stuck a pen lid into the bottom of the pear. It helps keep the pear upright while the mold sets and will leave a hole that’s the right size for pouring in the concrete mix later.
See what I mean about the cute pear butt 😉 I stuck the pen lid into a bit of polystyrene before mixing up the mold. It’s a trick I learned when painting polystyrene balls 😉
Mixing the Two Ingredient Mold
Put your gloves on and throw some cornstarch into a container. Cut the tip off of the silicone tube and put it inside the caulking gun. Squeeze some silicone into the cornstarch. Roughly the same amount. Then add some more cornstarch on top of the silicone and stir using the plastic knife. It’s probably best to do this outside. Silicone has an incredibly strong vinegary smell. When it looks like it’s almost mixed, start kneading the mixture until it forms a stiff paste that resembles bread dough.
If the mixture is too tacky or sticky, add some more cornstarch. If it’s too dry and flaky, like in the piccy above, add more silicone. Once it’s ready, flatten it out a bit and wrap it around the shape you want to cast. About 7 to 10 mm thick is perfect. That’s about 1/4” to 3/8”. Make sure you squish it into all the nooks and crannies.
Sit back and wait for it to dry, probably about ½ hour depending on the silicone you used. Use a sharp knife to cut the mold and remove your form. The two ingredient mold is very pliable so you can just peel it off. If you’re molding a pear, please don’t eat it. Rather wash it off again and add it to the compost heap.
Use super glue and carefully glue the two halves back together again, and it’s ready for casting.
Casting the two ingredient mold
You can either use concrete or plaster of Paris. I didn’t have to add any kind of release agent, I simply mixed up some concrete and poured it inside the mold. Just make sure you shake it around a little to get rid of any air bubbles. Once the concrete sets, carefully cut along the seam lines and remove your form.
The two ingredient mold can be reused over and over again, just wash it off, and you’re good to go.
To finish the pear off, I used some copper paint to create that 5-star restaurant look and added a bent, rusty nail as a stalk. The leaf was cut from a piece of metal that’s been lying outside in the rain for a few months.
A little bit of rust always works for me.
The easy two ingredient mold works really well and can be reused over and over again. And I do so love that combination of concrete, copper, and rust.
Just a word of warning. Once you make your first mold, everything looks moldable 😀 We’ve turned an old broken doll into a garden ornament and even created our own Egyptian cartouche using the two-ingredient mold.