casting parts at home

sounds crazy, right? I finally landed a classic cassette player model I've been chasing for 6 years and I find that 1 nylon gear and a nylon idler tire 'rim' is cracked and is unavailable. I saw a guy cast a gear in AL using the lost wax method: a silicone mold is made to make a relief of the glued part, then he cut away the gear carefully and filled the mold void with wax to get a perfect wax replica of the gear. He then placed it in a plaster casting and let it dry. He then dug out a drain hole to the wax and put it back in the kiln inverted to let the wax melt out. What was left was a perfect gear shaped void ready to fill with AL (in my case lead as it melts at a much lower temp and sets slower, avoiding casting flaws). His gear was about 4" across. mine is .250! The nylon gear is pressed onto a shaft that opens the crack (between teeth) and jams the other gear when it comes to the fault. with any luck Ill be able to replicate this gear in lead and have my cassette player up and running. Anyone ever cast resin or other material? 3D printer would be F'n awesome but Im not sure if it could be precise enough for a .250 gear? Id be happy to reimburse anyone that could 3D print it for me. I could CADD some plans if needed.