# Stuff to turn machined parts black



## finsruskw (Jun 3, 2020)

What is it called and where can it be had?
Viewed a couple threads where folks placed parts in a solution and it dyed them black oxide? like.
Curious as to what this stuff is.
Finishing up some Tee nuts and would like to do this to them to keep from rusting.

Thanks!


----------



## Moderatemixed (Jun 3, 2020)

Caswell Canada Black Oxide and Sealer. Worked SO well on my Atlas Lathe restoration. I also Birchwood Casey Super Blue from Cabbalas. There is a specific one for Aluminum. Amazon has the aluminum stuff.

Cheers,

Derek


Sent from my iPhone using Tapatalk


----------



## brino (Jun 3, 2020)

I have not yet tried it, but this is a link I saved to my local source:

Birchwood Casey Super Blue: 
https://www.cabelas.ca/product/370

It was recommended on this site.
I thought the price was reasonable.

-brino


----------



## Buffalo21 (Jun 3, 2020)

So I can’t use a wide tip Sharpie??


----------



## finsruskw (Jun 3, 2020)

Brino,
Does this stuff from Cabelas just brush on then?


----------



## benmychree (Jun 3, 2020)

To my experience, none of the cold blue products really work very well, they do not offer much permanence nor rust protection.  One rather easy way, if heat treatment may not be an issue is heating to a black heat and quenching in oil, the best is hot blue, using nitrate salts melted to 600 - 650 F; dip the parts in until the color is as desired (does not take long) remove and quench in warm water, then into boiling water to remove salt residue, then into hot oil.  I posted this process in more detail sometime in the past, it is the US Armory method of bluing, the result is very durable and rust resistant.


----------



## brino (Jun 3, 2020)

finsruskw said:


> Brino,
> Does this stuff from Cabelas just brush on then?



Sorry, I do not know.
I have not tried it yet, but I do have some future projects where I will.
So no direct experience......however......

This video:





shows just wiping it on, and then rinsing off within a minute.
(starts re-bluing at about 1:23 after cleaning off all old blue and rust)

-brino


----------



## Bi11Hudson (Jun 3, 2020)

In my model building, I am more interested in colour than permanance. There are several chemicals from Birchwood-Casey for steel. They vary in price, upward for more "permanance".  Refered to as "Cold Bluing", they are by no means as good as "Hot Bluing". Mostly as a touch-up for a gun smith.

What I mostly use is the colouring agents for brass and aluminium. They are acidic, requiring washing in clear water with a little added soda, after the colour has taken. FWIW, ZAMAK contains a large proportion of aluminium. The "Aluminium Black" works quite well on ZAMAK, albeit slower than on the direct metal. I have not tried any on copper, that may be an experiment for "one day". I have to assume the steel bluing agents work similarly.

The quantities I use are "3 oz" / 90ml bottles. A little goes a long way as I use it. I use a natural fiber bristle artist's brush (#10?) to apply. Prewashing is done with automotive carburator cleaner and I wear rubber gloves when prewashing. Any stain or oil on the metal will disrupt the chemical reaction.

My supplier is Brownells, 





						Brownells - Firearms, Reloading Supplies, Gunsmithing Tools, Gun Parts and Accessories
					

Browse thousands of firearm accessories, gun parts, gunsmithing tools, reloading, and shooting supplies for competitive and recreational shooters and hunters.  Brownells has a 100% satisfaction guarantee.



					www.brownells.com
				



Their "root" page, searching from there. I don't know how their prices compare to other vendors, I just use them because they "sit in my mind".

Bill Hudson​
.


----------



## pontiac428 (Jun 3, 2020)

Ospho Rust (phosphoric + chromic acid) blackens steel readily when applied hot.  It may not be pretty enough of a color for a gun, but it's good for tools.


----------



## Moderatemixed (Jun 3, 2020)

The Caswell stuff has lasted on my lathe. Still looks as it did when I finished the restoration. Say 2 years ago. 


Sent from my iPhone using Tapatalk


----------



## benmychree (Jun 3, 2020)

The cold blue products that I have tried seem to be a mixture of copper sulphate, a bit of acid and selenium; the copper sulphate plates copper onto the bare steel, and the selenium turns it black, a very thin coating of very limited durability.  As Bill Hudson relates, any oil or fingerprint on the metal disrupts the bluing process with cold blue processes, that is the beauty of the hot blue process that I described, the parts do not have to be hardly cleaned at all, in fact a thin film of light oil can cover the whole part; when it is immersed in the niter, it visibly burns off with a glow, completely covered by the niter, which is a 50/50 mixture of sodium nitrate and potassium nitrate, and is the lowest melting point of any salt mixture; individually, they melt at over 1,000 deg F. at the mixture of 50/50 the temp. is less than half that, and will be a slush at under 300 F.
I was introduced to the bath when I was an apprentice, the company used it for a tempering bath for heat treating of tool steels, I accidently discovered that it would blue steel parts also, only several years ago I came across a article in American Machinist that further described the process in detail.


----------



## aliva (Jun 3, 2020)

I second the Caswell product, been using it for a few years, good results


----------



## MrWhoopee (Jun 3, 2020)

Here's a process you can try using commonly available ingredients. It does produce a true black oxide.




__





						Quick rust bluing--- Back in black!
					

The black finish left by the Birchwood-Casey Super-blue just wasn't doing it for me this day.      The photo misleads, making them look a b...




					mypeculiarnature.blogspot.com


----------



## SLK001 (Jun 3, 2020)

Here's a video of a 1-hour rust bluing procedure using common household items.  It also produces a true black oxide.


----------



## Aaron_W (Jun 3, 2020)

MrWhoopee said:


> Here's a process you can try using commonly available ingredients. It does produce a true black oxide.
> 
> 
> 
> ...



I recently bought everything to try this out, but haven't had a chance to actually do it yet (need to finish the parts that need bluing). The price is right, just a few dollars of readily available household chemicals.


----------



## finsruskw (Jun 3, 2020)

Wow!!
Everything one always wanted to know..…...

Thanks for the replies folks!
Some of these commercial products sound quite involved


----------



## derfatdutchman (Jun 3, 2020)

For small steel parts you can also do a heat blue. Heat your part until it turns dark blue, when the color is reached dunk the part in oil.


----------



## acruxksa (Jun 4, 2020)

Brownell's Oxpho Blue.


----------



## TTD (Jun 4, 2020)

acruxksa said:


> Brownell's Oxpho Blue.



^^^ This stuff if you’re going the cold blue route.

Although I personally prefer rust bluing myself (never tried hot salt bluing so can’t comment/compare), when it comes to cold blue, Oxpho-Blue (or “Black Chrome” as I call it) is definitely my favourite....and I’ve tried most of them out there. I find it is a bit more resilient & better looking than other cold blues I’ve tried ( Birchwood-Casey, Outers, Van’s etc) but at the end of the day it _IS_ still a cold blue & as such won’t be as durable as other methods previously mentioned.

Unfortunately, Brownell’s won’t ship it to Canada anymore , so I have been quite hesitant about using the last 40-50 ml I have left


----------



## acruxksa (Jun 4, 2020)

TTD said:


> <snip>
> 
> Unfortunately, Brownell’s won’t ship it to Canada anymore , so I have been quite hesitant about using the last 40-50 ml I have left



I can't get it shipped to Alaska either, however, our local Cabela's stocks it, but it goes fast.


----------



## kvt (Jun 4, 2020)

I just got the kit from Caswell for black oxide treatment.  Using it on parts for a old Hit and MIss engine I'm working on.  does look good.   
will see how it last.


----------

