You can use vaseline thinned down with meths as a thin brush on release agent to stop the silicone sticking.

Alternatively, don't use  silicone for making the initial copy.  Cast the initial mould in silicone, then cast the first copy in the casting resin you plan on using, then take a final mould from that.  I presume you are doing the double moulding process so you can make some changes ?


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Hi,

I am hoping to make a small run of electrical products that need to be cast in black resin.

In order to do this I will first need to make a silicone mould of ‘part a’.

Once I’ve made the mould I want to cast a silicone copy of ‘part a’.

Finally I would like to use the silicone copy of ‘part a’ to make another mould which I will then use to cast my final part in resin.

My question is, how do I make a mould for casting silicone as I assume wet silicone will bond to dry silicone? If this is the case does that mean that I can add to a dry piece of silicone with wet to make a more complicated mould?

Thanks, Stephen