For the crochet work that I have been doing lately, I have found that 0,3 mm is a nice dimension of metal wire. In the jeweller training, which I did in French, this was referred to as “trois dixième” (3/10 or three tenths). That’s between gauge 28 and 29 if you’re not in the metric system.
When annealed, it is flexible enough to crochet with without too much effort, and it can still hold the shape fairly well after it has been hardened.
Metal wire below: copper, brass and sterling silver.
If you need to make finer wire, you can pull it through a wire drawplate and gradually go down in diameter.
After pulling a few times, the wire gets hardened and needs to be annealed before proceeding. I am happy when I can buy the dimension I want, as this is a pretty time consuming process. It’s nice to do it all yourself, but it also takes time.
The finer the wire, the more careful you have to be when you anneal or do solder work. If it gets too hot it will melt, and with fine wire, that can happen very quickly if you don’t pay attention.