This guy’s project is tremendous:
“Carbonating tap water to make seltzer is easy, fast, and absurdly inexpensive with my improvised apparatus. All that is required is to place CO2 gas in agitated contact with chilled water for a few seconds. In this essay, I’ll show you how it is done with easy-to-find parts and common PET soda bottles. I’ll also explain the kinetic chemistry of why it works so well. And in the second half of this essay, I’ll explain how I progressed from this improvised apparatus to installing a complete soda fountain in my home.”
I’ve been interested in this for a while but one of the challenges is refilling the tank if you don’t have a car. It doesn’t seem like a great idea to put a 50 lb weight on a bicycle even if the basket’s rated for it, which it’s not.
Someone gave me a soda stream machine a long time ago. I bought an adapter that allows me to use paintball tanks; these are on the small side and fairly light, which would allow you to do it on a bike.
Each tank lasts me a month and I have 4 tanks.
Alternatively, you can adapt everything the site says but for a smaller tank, you don’t need to buy a gigantic one. So his gear with a few small paintball tanks would work nicely for you.
Oh that is a cool idea! I’ll look into it.