I’ll give you an overview of my attempts at blueing steel, but if you want a much better explanation, watch this video on the clickspring Youtube channel for quite a professional method and this video from Michele Cominetti for a more DIY approach.
To turn steel blue, you have to bring it to a specific temperature around 300 degrees Celsius or 575 degrees Fahrenheit. I tried different setups with the piece to blue either directly on a piece of brass that I would heat with a blowtorch or in a brass or steel box, laying on small pieces of brass, and even directly in contact with the heat source dangling from a piece of metal.
I haven’t been able to obtain good results, either because I don’t have the patience to slowly bring the piece to the right temperature or because I don’t have the right setup. The hands are 3D printed, so maybe the steel is not as uniform as it would be if it was made with a traditional method. It is also extremely thin, 0.4 to 0.5mm and therefore heats up very quickly.
The results are far from perfect, but they are certainly interesting and unique and I’m sure with a little more care and patience they could be improved.