18.8 to 14.4mm adapter

- print both parts
- tape together (I used masking tape)
- mix up some silicone. I used 2 component platinum silicone
- either pour it into the mold and shake the mold to get rid of bubbles or inject the silicone with a siringe
- let it sit until cured
- remove tape and secure lover part in vice
- turn the upper part until the silicone gives a bit and remove it.
- insert into 18.8mm waterpipe or lab glas and enjoy.