Tuesday, May 26, 2015

Cornstarch and Silicone Molds DIY

I love making my own silicone molds but the molding putty can get expensive!  Well, not any more.  Check out my cornstarch and silicone molds that cure in about 20 minutes!  These molds are super easy to make (also a bit messy) and you can make tons of them for very little money.  In my crafty lab, I found that air dry clay, Sculpey and 2-part plastics work best in these molds.  If you're not familiar with 2-part plastics, they are wonderful and cure in about 10 minutes.  I'll put a link to where you can get some below.  Have fun, go forth and make molds!
xo, Mark!
The stop watch mold is one of my favorites! 
 Add a little paint to give them some color!
Try the putty on a small statue or doll face!
Watch the short video tutorial here
Learn how to make Rubber Stamps with a similar method, here!
Baby oil
Mixing bowl
Objects to cast
 Squeeze out enough silicone to cover your object
Add in about 1/2 the amount of cornstarch
Add a small dab of Americana Acrylic Paint
Add in several drops of baby oil
Mix thoroughly with a small spoon or stick
*Cover your hands in cornstarch and knead
Roll the putty into a ball
Press in your item making sure it covers all the details
Let cure for about 20 minutes
Remove the object
Fill with 2 part plastics, Sculpey or air dry clay


  1. Great info ...thanks for sharing. I am assuming this is not food grade?? for fondant etc??

    1. Hi Carol, This is strictly craft grade.....no food. Great for clay, hot glue, plaster, 2 part plastics, melted plastics and can sometimes work with resin, but it depends on the silicone used. It's hit or miss.

  2. Awesome tutorial, Mark!
    Thanks for sharing :)

    By the way, which is the use of the baby oil in this mixture? Makes the mold more flexible or easier to work with?

    1. I'm not 100% sure about this, but I believe it helps as a releasing agent in the mixture. The oil makes it easier for the clay or 2 part plastic to release after it's set.

    2. Ooooh! Thank you so much for your help, Mark!
      I'm trying this in a few hours and I'll let you know the results ;)

    3. Yay! I can't wait to hear about your results! Wear gloves if you can, it gets very sticky!

  3. I know this post is from a year ago but i need help! Ive done everything you said except i used vegetable oil instead of baby oil. It will not cure. Every object i cast pulls out half the mold. I let it sit overnight and still nothing.

    1. Hm.....I'd try the baby oil for sure. Also, if you have a torch or even a long arm lighter, you can heat your resin piece (if it's sticky) a couple of times and that should facilitate the curing. I assume you're using resin? Resin can sometimes react to silicone.

  4. Can you substitute flour for the cornstarch