Interesting video on turning steel black?

[davidphilips]

View: https://www.youtube.com/watch?v=5Sty5upsadY&feature=share&fbclid=IwAR3jVUUPcd6N804hK3OmE6NcjQ1Iheap5wqiY0zakl4hYk4nVUShRbUA1lE

 

[Electric_Andy]

Yup bluing liquid is used in a lot of metal work and restoration. Seals and protects it from rusting if you don't want to paint it.