1. What is the best way to determine how much metal (I will be
casting in sterling and/or fine silver) to melt for the item
itself and the sprue button if the model is made of sterling,
plastic, fimo, sculpy, or any other material? Are there any
guidelines that could be applied?
My brief encounter with the delft system tought me that if you melt
more than you think is needed and pour out the rest into a water
bucket, its less trouble than determining weight needed.
Someone suggested putting the canisters into a 200-300 degree
oven, but it was not clear when this could be done. Would it be
helpful (or even sensible) to put the canister on a small
ultralight kiln (that's what Rio calls them) while pouring the
metal? That might help to keep the bottom part of the assembly
hot--has anyone tried this?
I have tried placing the finished mold in a toaster oven @ 300F for
20 minutes and it helped alot, I stopped getting part-fills. As for
your idea of using the Ultralight kiln there might be a problem with
over heating the bottom of the mold and it might burn the clay. One
suggestion was to make the sprue a minimum of 5mm in diameter, and
vent vent vent! I've had much more success pouring gold using the
delft clay for some reason. Keep in mind that gravity will only do so
Hope this helps.