How are stemless waterpipes or rigs made? (Ex. Avant Garde or Salt’s Ripcurls)

Very carefully.

Sometimes like Avant Garde, the glass is cold worked to get the holes and lines.

As for Slat’s design, he presses in the side and then covers it with glass making a tube.  This takes a lot of time and patience but is super dope.

We feel is the holes get to small like Avant Garde, it requires a lot of cleaning.  But, it’s well worth it!