3D print the wax would be good and would allow you to design the parts more accurately- then plaster around it to make a mould
Yeah, so 3D printing wax is definitely an option. Also as I mentioned, PLA can be used, but it does unfortunately not burn out as cleanly so you can wind up with some flaws. If you’re painting or powder coating after casting, maybe that’s not such an issue, but careful consideration is necessary to make sure you’re not weakening the integrity of the casting by filling it with voids of ash.
Or I don't know how many times the plaster mould could be used, but probably not too many times?
If you’re talking about making a plaster mold to create the wax parts from, then those last a long time– you thoroughly wet the mold and then pour melted wax in and let it set to the desired wall thickness before pouring the remaining wax out. Since you keep the mold wet, the wax doesn’t seep into the plaster and deteriorate it all that much if you’ve made it properly.
If you’re talking about the plaster mold that you actually cast the metal into, that’s called your investment mold, and it’s a single use thing. Each individual casting is invested, burned out, cast, and then you smash apart the mold to reveal the casting inside. The most cost effective way to make it is equal parts sand and plaster, and you reinforce it with a chicken wire “cage”. You then have to burn out the wax or PLA in a kiln, and that definitely is one of the biggest costs in casting since the electrical cost (or gas if you’re snagging a cheap gas kiln on Craigslist) for a firing like that is probably around $40+ (at least here in NY) so you really want to make your investment molds as compact as possible while still being strong, and to burnout as many as you can pack into the kiln at once so the cost per unit goes down. There’s also a product called Suspend-A-Slurry which I’ve seen some YouTubers use instead of a more traditional investment mix, and it definitely seems to cut down significantly on the labor that goes into investing the wax/pla but I’m not 100% sold on how reliable it is, and it’s also probably a bit more expensive than the plaster/sand costs (but then again, who knows— plaster has gone up a lot in cost recently; my most recent castings I did in school used probably around $60 worth of plaster for just two medium sized molds)
I have pretty good documentation of most of the process of making a sculpture in bronze, so I could maybe make a tutorial thread at some point. I haven’t cast any enclosures since I don’t have a home foundry setup yet, but the process would be pretty much exactly the same for any sort of lost-wax/pla casting.