Gun Black?

[The_Yellow_Ardvark]

I mused to have a bottle of what I called:
Gun Black.

When you used it on clean metal it would turn it black and give it a rust prove finish.

What is the real name of the stuff, plus were can I buy some.





want to blacken these or give them a gun metal blue finish.

 

[colnerov]

Hi, I think it's actually called 'gun blue'. However I've just watched a video on Youtube and he used white vinegar. -

Colin

 

[slim_boy_fat]

Gun bluing

EDIT: Fastest finger first......^^

 

[ihavenoidea]

The Prozess is called blueing. You can find various liquids on eBay with that name.

I personally prefer Manganesing with
phosphoric acid and Manganese dioxide over blueing.

Mfg,
David

 

[colnerov]

Gun bluing

EDIT: Fastest finger first......^^

It doesn't happen often.

 

[Maker]

Cold bluing is usually done with selenium dioxide.

 

[fixerupper]

I alway thought it was done by heating until cherry red and then quenching in used engine oil ...am I wrong ?..

 

[Wozzaaah]

^we did that in metalwork at school back in the early 80s.
It was known as “oil blacking” back then.

 

[Paul.]

Frosts do a cold chemi blacking kit, Ive used a few of them over the years, deffo a rubber glove job though, unless you want odd coloured fingers

https://www.frost.co.uk/frost-metal...ulyaMGdSYwmiHbFOO2Wzfa_0BpF-dYjRoCRLoQAvD_BwE

 

[slim_boy_fat]

Frosts do a cold chemi blacking kit, Ive used a few of them over the years, deffo a rubber glove job though, unless you want odd coloured fingers

https://www.frost.co.uk/frost-metal...ulyaMGdSYwmiHbFOO2Wzfa_0BpF-dYjRoCRLoQAvD_BwE

And cheap enough for a 'give it a go' effort....which is nice.

 

[ronan]

Bluing is actually passivated rust, if you heat red rust with boiling water its becomes black oxide, magnetite which protects the steel from further rust.

 

[ronan]

I alway thought it was done by heating until cherry red and then quenching in used engine oil ...am I wrong ?..

Thats not really bluing as such, but i have used that method to blacken things. The brake lever on the bridgeport head for instance, it was badly bent, so i reddened it up with the gas torch and straightened it, then chucked it into some manky black engine oil, turned out great.

 

[stuvy]

I was always under the impression that would make the hammer weaker

 

[ronan]

You can boil the steel parts up in caustic soda, thats supposed to make it blacken. Any of these cold blues solutions like the Birchwood casey stuff is not very durable, in my experience.

 

[grim_d]

The selenium based cold blue works fairly well if you are extremely stringent with the prep and cleaning it however does not prevent rust...it gives a better surface for oil to cling onto without being too "oily"

It's not a terribly robust coating but the better you do the whole process the better it is.

Real gun blueing is a completely different process.

Saw that paskmakes way the other day.. very interesting I'll need to give it a try.

Obviously some items are not suitable for heating too much.

Here are my multifix toolholders which I blued after they were rusting over winter...it's holding up very well indeed. Phillips cold blue.

 

[Yamhon]

IIRC there are two types of blueing, only one of them offers any rust protection and I don't think it offers all that much. I've considered Cerokote in the past instead, but havne't used it yet.

 

[Migmac]

Birchwood casey do bluing kits.

 

[merryman]

True "blueing" is a heat treatment process, it was used by clockmakers and gunsmiths, and is simply the oxide film produced when you heat steel, it is used as a guide to tempering, ie, hard quenched steel can be tempered back by heating to "mild straw" colour for chisel points etc, blue is used for clock springs, but also as a decorative process on screws, balance wheels, gun parts, etc. Because you don't want to temper certain parts, a chemical "cold blueing" process was developed. There are other blacking processes which give a protective finish, parkerising being the most commonly used.

 

[gordon stephenson]

I have done plenty of oil blackening, to finish and protect clean metal, Certainly no need to heat anywhere near red, heat with a blow torch etc and just keep dipping into the used oil, item usually gets on fire when lifted, then dip it back in, Repeat until you get a nice satin black,

 

[Tangledfeet]

Frosts do a cold chemi blacking kit, Ive used a few of them over the years, deffo a rubber glove job though, unless you want odd coloured fingers

https://www.frost.co.uk/frost-metal...ulyaMGdSYwmiHbFOO2Wzfa_0BpF-dYjRoCRLoQAvD_BwE

Would all mill scale have to be remove for this to work?

(Newbie question - I'm assuming it would!)