Blackening for steel work

[m_brothers]

I have used-
-Wire Brush, then reheat to just hot, no color, apply a candle, and if it catches fire wait a little bit, if it just smokes then i run the candle up and down the metal, once cooled, wirebrush again. This one works best for me.

-Wire brush, then heat to warm to the touch, vegetable oil.

[Hofi]

Cut ONION in two halfs heat the steel not too much with a rose bud smear thw onion on the steel and u get it black. put whatever transperent finish and u get a very good
black finish result
hofi

[Chrispy]

Parkerising is a good method. Manganese dioxide and phospheric acid and some iron filings for good measure (not sure of the quantities but you will find it on the net). Mix the ingredients and heat to 53 degrees (a bit hotter than luke warm) and insert your (oil and grease free) piece of metal for about 45 minutes. Best to use a glass container - not your wifes saucepans. Easily done on the kitchen stove but be ultra careful as acid is not your best friend. It needs to be rinsed off and dried immediately after removing from the hot solution.
I made a mild steel tank 3m long x 1.5m high x 200mm wide (1500 litre capacity)to Parkerise some wrought iron gates I made a few years back. They turned out great. The parkerising makes a film microns thin that act like a sponge that sucks in whatever you choose to protect it with. Paint, resin, or oil.
Parkerising is a finish ofter used for hand guns, tools, engine parts etc. It has an extremely hard wearing surface particularly if oiled afterwards. 15 years of constant use and cleaning as with hand guns is not unreasonable. Ingredients are available at your local chemical store. Permits not required to purchase these chemicals.
Chrispy