Blackening of metal

[Karl_H]

From the YouTube site:

Do it outdoors. Components may cause burns

Degreasing Recipe:
Per 1 liter of distilled water:
50 g of caustic sodium(sodium hydroxide, caustic soda)
50 g of soda ash
10 g of liquid glass (silicate glue)

Burnishing Recipe:
Per 1 liter of distilled water:
500 g of sodium nitrate (sodium nitric acid, NaNO3)
500 g of caustic sodium ( sodium hydroxide, NaOH)