I recently wanted to get a feel for how difficult casting may be. A bit of trial and error going on here which seems a subject with actually very little detailed information on google – lots of high level but I failed to get any decent examples.
So jumping in I used some rubber tool silicone to make a negative cast which I then made a wax mould from which in theory I could then cast with investment powder. Lot more experimenting and a good book needed to proceed I think. But not a terrible outcome from an afternoon just jumping in and experimenting.
The idea being that with a good wax cast (and I think I had the wrong wax) I could make a number of patterns that I could cast in brass using some equipment available to me.