Questions about silicone molds

[Techuser]

I'm doing my second sculpt now and ordered a bucket of silicone to try making some molds, my questions are regarding the filling for casts. Is it ok to cast from the resin used in fiberglass? And why do the kits we see around are hollow, if when I pour the resin into my mold it will be solid thick?

 

[juntari]

The casts are hollow because they are probably slush cast. You pour in a small amount into your mold then rotate it around so that it all gets covered with a thin layer. Then you repeat that over and over again to build up a thickness, keeping the inside hollow.

 

[fettster]

You can use polyester resin but it will be very brittle. If your slush casting, it's far better to use a polyurethane resin.

 

[made007]

2part urethane plastic works for me, i do the matrix mold for my predator bios