Silicone/ Latex cast= stonemold?

Kai Rottmann

Hello dear community (=

My new project is going to finish and i thought, i could cast that sculpture in silicone.

But: At this time, i am doing a siliconemold with Moldmax 30...

Question: Is it necessary to have a stone- or resinmold, if you want to cast something out of silicone or latex?

There arent any straight Informations about that. In the most videos i can see, that they are using stonemolds when cast something in silicone... but nobody says: "You have to have a stonemold..." 

My project is a livesize bust, which should have a silicone skin and a foamcore. I am thinking about to use the slush cast technique with a fx- silicone to build up the skin.

Has anyone experience with that or could give me some tips?

I would be happy to receive answers 

Greets

Kai

Chris Ellerby

Hi Kai,

Stone molds like Hydrocal are good when you are working with liquid latex (like for making latex masks) as the Hydrocal wicks away moisture allowing the latex to form a skin on the inner surface of the mold.

Foam latex can be run in Ultracal or Hydrocal, as long as the stone has time to dry so you don't get steam pockets.

You can cast silicone in a stone mold, but if you want to run a lot of copies a resin/fiberglass mold.  But for something you only want to run a couple copies of you can save money and use stone.

Also, you want to avoid casting platinum silicone into any mold that has previously been used to cast foam latex or liquid latex, as latex will inhibit the curing of the silicone.  You can clean the mold and run both, but it has to be a deep cleaning which can be a bit harsh on stone molds and reduce their life.

For larger molds (like a bust) I like to use fiberglass because it's nice and light weight.  A bust sized stone mold can be very heavy, and heavy molds tend to get dropped.  And dropping a stone mold involves far more tears and cursing than dropping a fiberglass mold.  But if you want to save some money (and can get someone to help move the heavy mold around) you could use Untracal. (with hemp, burlap, or other reinforcement)

/Chris

Kai Rottmann

Thank you very much Chris! (=

I have seen the Stonemold- lesson yesterday and i have ordered a 20 kg bag Ultracal 30 and some sheets of burlap 

The weight of the mold, is a very good aspect,.. I will have that on my "radar" [=

I will try to cast Latex in my siliconemold by brushing the first Layer and after its dried, i will fill the whole mold and pour the Latex out and let it dry again.
Repeating that step a few times, should build up layers of Latex.

I will report and share my experience ;-)

Thanks again for your help.

Greets 

Kai