Casting silicone in different durometers

Hi Core,

I wanted to experiment with casting electronics into silicone or possibly urethane.
I was hoping to be able to cast the parts in different degrees of ‘stretchiness’.
Does the shore hardness give a good indication of how stretchy the cast silicone will be?

Also I noticed that the silicone mold-making/casting products came with additives to increase or decrease the viscosity of the silicone while pouring. Could these possibly be used to make the final part more/less stretchy

I suppose I could use any flexible casting product. I called the local tap plastics to ask but their response was “Silicone is not a casting product… you can’t do that…” I was fairly certain you could, aside from casting platinum based silicone in a tin based mold.

Could anyone shed any light on the subject for me?
Thanks so much for your help!

Sounds like you got to speak with a “sales person” who only knows what is in their “Casting Products” section, but not what you can do with their products. I have not used it, but TAP’s Silicone Thinner is advertised to reduced viscosity, lengthen cure time, and decrease durometer (hardness, in their words).

That said, I think you’d have better luck getting answers to your questions from someone at Smooth-On > Encapsulation & Display with Smooth-On Materials

I agree with Lmo. Contact Smooth-on. They will get you exactly what you want. I have never been disappointed with their products and they are always very helpful.