I am not sure if this method has been mentioned.
When I cast organics, I first sprue up heavily and then mix up some
casting plaster to a cream consistency and then paint the object with
it all over.
I use a soft small paint brush.
Then I wait until it starts to gloss over and I mix a little more
and paint it over again.
I do this about ten times.
I make sure that the coats have not completely hardened before I
paint the next one, otherwise they will separate during burnout.
Then I mix the rest of the investment, vacuum, and pour over the
Then I dry the mold out in the oven for about six hours at 100C to
The slower the better, the mold must be completely dry.
Then I ramp up to 800C and keep it there for 3 hours.
Then I cast at 700C and I use a spin caster and I wind it up an
extra turn from normal.
(Normal is 2.5 turns and normal casting temp is 500C.)
Don’t believe the yada about sulfur contamination, it’s BS.
Then I quench the mold in water.
Here is a picture of an insect that I cast.
Note the feelers and the fine detail that can be achieved.
The insect is unmounted at the moment, so that’s why everything is
folded back and the legs inwards.
About 70mm in length.