How do I work this out? (casting)

[Vanessa]

Hello my current project at uni is multiple production (casting). I've made a piece of jewellery that combines metal and milliput (as per project brief) I now need to get this cast in metal. So how do I work out the specific gravity and therefore the cost once cast in the metal of choice? Do I need to know its weight in wax or can I work it out from my model in its current state?
Thank you

[ps_bond]

I'd work out the volume displaced by the object, then apply the SG of the metal to cast it in.
http://eprints.qut.edu.au/19356/1/19356.pdf

[Vanessa]

Thank you 😊 a bit of night time reading there for me but what I have read seems to make sense 😊 thanks so much 😊

[josef1]

If your making multiple objects you will you need to make a mould ? if so the easiest way would be to inject the mould with wax, then weigh the wax then multiply that by the specific weight of the metal you want to cast , sterling silver is 10.5, 18ct gold 15.5, and platinum 21.5 approx

for example if the wax weighed 2 grams it would weigh 31 grams in 18ct gold .

http://morrisandwatson.com/commonly-used-formula/ you will also need to allow for the casting sprues and button