Summary

Bubble wands, ribbed for your enjoyment. The ribbing holds more mixture, allowing more stable bubbles.

Instructions

Download and print bubble_wand_ribbed_2.stl, then make bubbles.

My most successful homemade bubble solution is made using the most plain bar soap I could find (e.g. castile, or eco-store brand). This is nowhere near as successful as the shop-bought bubble solutions:

Put about 1/8c of broken soap pieces into a container.
Add 2c boiling water and mix

2a. Further heating / mixing may be needed depending on how broken the soap is

Leave until cool. This will generate a thick gel-like substance (liquid soap)
When ready to bubble, combine 1 part gel solution with 5 parts boiling water

My first iteration had the ribbing on the inside, which made the bubbles more likely to pop as they left the wand, particularly when made only half-height due to a reprap disconnection mid-way through.

The second iteration has ribbing on the top surface, but not any sides. The angle of the ribbing tries to draw the mixture into the wand centre. The wand seems a bit too thick though -- I notice that other wands are 2mm square profile. The second iteration makes fairly nice bubbles, but they don't close easily.

The third iteration has ribbing on top, bottom and sides. The ribbing is variable width to try to encourage more bubble nucleation, but not as sharp as in the first iteration. The model has also been reduced to a 2mm square profile for the wand part, as well as removing fillets (which made my reprap pause for far too long). It seems to do better at closing bubbles, but the model is probably more complex than it needs to be.

The fourth iteration has angled prongs, and more internal places for the bubble mixture to reside. It's also constructed entirely in OpenSCAD, as I'm a little bit more practised in that now.

A nanopore version of the bubble wand has also been produced, inspired by the micropatterning of the Oxford Nanopore MinION flow cells.

I've since discovered that my gear generator also makes it easy to make ribbed bubble wands. Yay for serendipity!

Ribbed Bubble Wands