Mold making is yet another thing I’ve had tons of interest in for a long time, but have never really done much of it. The one occasion that I tried it out was to make some climbing holds, which worked surprisingly well, actually. I was able to find everything I needed at inventables.com so I decided to give it a go.
I was surprised at how well it worked on the first try. Although the mold wasn’t perfect, and the cast wasn’t either, they were both really close.. and for my purposes, good enough. Having done some research, I found that having a vacuum chamber (I have to see if I can make one of THOSE) is hugely beneficial for removing the air bubbles from both the molding and casting materials.
Check out my process below, and if you have more experience with silicone molds, please leave some tips and tricks in the comments below!
Measure your item, then add 1/2″ to each side.
Measure out four strips of plastic or foamcore for the box sides.
Cut the sides out, just make sure the height is well above your object’s height.
Cut a square for the bottom piece of the box.
Hot glue your object in the center of the box bottom.
Hot glue on the walls of your box.
Seal all cracks with hot glue.
I used Oomoo 30 for the mold material.
Mix the parts at a 1-to-1 ratio.
Mix thoroughly, scraping the sides and bottom fully.
Slowly pour into your mold in a thin stream to reduce bubbles.
After it’s cured, remove the box from the mold.
Cut a serpentine pattern on two sides.
When you’ve opened the mold enough, remove your object.
The molds maintain ALL of the tiny details.
Spray the inside of the mold with a release agent.
Using wooden side supports, tape the mold to keep it closed.
Mix your resin. In this case, I used a 1-to-1 mix urethane resin.
Slowly fill the mold, spinning the mold to fill pockets and release air bubbles.
After it fully cures, remove the cast item.
Check out the final result!