I'm well pleased with the trocho pocket plug-in, it's a major step forward in being able to make hardwood clock wheels sucessfully.

How are you designing the ring of teeth for the pulley? I have the Gearotic software which can create accurate timing pulleys in all sorts of formats. If you need help with that I can send you a PDF for importing into CamBam (that's another plug-in).

Well if you want to get into a new hobby that involves playing with fire, melting aluminium is easy. The YT video below gives you the idea. Use previously cast aluminium alloys (old water pumps from your friendly neighbourhood motor mender etc.) rather than cans or other scrap. Sawing off the bottom of an old fire extinguisher makes a good crucible. Getting a sucessful cast with it is another story however.

Not sure on the use of 2-part plastics for something this robust or how well they machine but one option to consider is to make a master in MDF with your CNC machine and then a silicone mold to cast the final pulley ring, or a blank for final machining. I've done a bit of this for arty stuff but not for engineering. You aren't going to buy from Australia but the Barnes site linked below has info on materials and how to use them. Similar stuff will be available in Pommieland.

https://www.barnes.com.au/

https://www.youtube.com/watch?v=lSoWxG30rb0

Good luck

Kit