Making a mold:
- Print four outer mold parts (2 perimeters and 5% infill is enough)
- Join them together with adhesive tape
- Put inside inner mold part (printed in vase mode)

Casting:
- Mix cement with water (4:1 ratio)
- Pour concrete into mold
- Wait about 24hrs

Removing the mold:
- Outer parts should be pretty easy to disassemble, just cut the tape and they'll come off
- To remove inner part pour near-boiling water inside, wait until plastic gets soft and pull it with some pliers