I have just received my casting kit and i want to make a mould of some wheels for o gauge railway for some road wagons, in layman terms what sort of mix will i need its only a small part to be molded i hope you can help

David

depends on the volume of the part.

Build a casting box around the part so you use minimum silicone for the mould.

Not too hard if you made the box to measure it and calculate volume.