surface rust into black oxide or browning

I just got a steady rest for my lathe. The adjustment dials have a nice even coating of surface rust. What do I need to do to convert the surface rust into black oxide or browning? Gary P. Hansen

phosporic acid will react with the rust chage it to iron phospate. This can be a dark shade.

This conversion was traditionally done by boiling the oxidized item.

Gary- IIRC, usually rust blueing is done with a solution that creates a copper base, then boiled and carded off using a fine wire wheel or maybe 0000 steel wool, washed in alcohol or soap to remove the oil.
I am not certain you can boil a rusty item to turn the rust to black.-Jerald

Boiling in distilled water or captured rain water will convert the red rust(ferrous oxide) to black rust(ferro-ferric oxide)and will soften the rust making it easy to remove with steel wool or a soft wire brush. This is the same process used in rust bluing. Repeated rustings and boilings might be necessary to achieve a dark color. Ordinary potable water might not give satisfactory results depending on the mineral content.

RWO

There is a product called Evaporust which will turn the rust into the black variety and make it easy to remove. If the steel has a high carbon content, it will leave a hard finish much like parkerizing.

On replica rifle barrels I have been known to apply bluing solution over red-brown rust. The result is a pebbled black surface which suited the application.

Jerald,
unless you mean copper colored rust, there's no copper in rust bluing.

if one wants a nice even "blackening" you can strip the oil off the part (and paint)... get a big pot (turkey/fish frier) of water to boil (not matter what kind, for the most part, as long as it aint very hard or very soft

paint the stripped parts in "plumb brown" until you get a thick, even, consistant color of purple/brown....

drunk it in the boiling water....

dry and cover with machine or gun oil.. NOT wd40 or any penetrating (unles water displacing) oil, as it will see the nice blackening as "rust" and try to "get under" it to the metal... resulting in a sucky blue

let it sit a couple days, warm and oiled, before you try rubbing it down

LOTS of blues, hot or not, are ruined by using the wrong oil and the WAY WRONG technique of rubbing them down... bluing takes a couple days to reach final color and hardness... think of it as fresh paint

jeffe

LOTS of blues, hot or not, are ruined by using the wrong oil and the WAY WRONG technique of rubbing them down.

So don't stop there. (-: Enlighten us as to the correct processes and materials.

Red rust to magnitie

garyphansen said:

I just got a steady rest for my lathe. The adjustment dials have a nice even coating of surface rust. What do I need to do to convert the surface rust into black oxide or browning? Gary P. Hansen

Click to expand...

Yes, you can boil red rusted items and they convert to black. I think it goes from Ferric Oxide to Ferro Ferric oxide


Here is a before and after doing nothing else but boiling.