Making Moulds out of Mountains (...of stuff)

Yes, there are lots of tutorials out there about how to make moulds using silicone caulk and cornstarch. Here's my simplified version.

Difficulty Level 1 - super duper easy!

Materials Needed:

1) 100% silicone caulk ($6.25 for huge tube at Home Depot)

2) cornstarch ($1.35 for one pound box at Kroger)

3) a stir stick (anything stiff - an old wood Popsicle stick or fork)

4) a surface (I used top of an egg carton for easy cleanup)

5) caulk gun (if you're working with the giant caulk tube)

6) an object you wish to duplicate (jewelry, dolls face, even large toothed fabric for texture such as burlap)

Begin:

1) pour out some cornstarch (cornstarch and corn flour are two different materials)

2) squeeze out some silicone (about as much as the object you want to duplicate - or lots more cuz this is so fun you're going to make MANY!!)

Caulk squeezed onto cornstarch.

3) mix it together. If it's sticky, add more cornstarch. 

Mixing the two materials together.

4) when it seems well-blended, hold it in your hand and inner it. The texture is surprisingly like fondant and quite lovely. 

Once well blended, kneading by hand is best.

5) roll into balls the size of your mould. Smooth a layer of cornstarch over it 

A properly-mixed batch of mould-making substance.

6) press your object into the ball and set aside for an hour (drying times will increase with larger moulds)

7) once a hour has passed, gently bend back the edges and remove your object

Samples of moulds that I made.

More sample moulds.

Tips: Don't bother adding paint or baby oil or whatever thinner other tutorials suggest. They're unnecessary and complicate the process. Also, I paid more for this silicone because it has minimal oder. If you're working outside or near an exhaust fan, you can get by with even cheaper caulk. 

Btw, the objects that I pressed into the caulk mixture only needed a quick rinse of water when I pulled them out. A larger object, that I pulled out too soon, was slightly wet and some of the caulk remained in the object. The caulk washed away easily with a toothbrush and dish soap. I had sooooo much fun that I immediately made several more!!

Samples of how the fimo looks after I used it in the mould, along side the original.

Another sample of the fimo coming out of the mould. The pieces are not finished yet, however.