Subject: Blueing steel

From: Jeffrey Prothero <[email-masked]>
Date: Thu, 19 Sep 1996 18:59:41 -0700

Many years ago a friend reblued the barrel of my .22 rifle in a tank of
boiling solution of some salt.  This is of course the usual way blueing is
done.  However the salts that he used were not sold for use in blueing.
They were sold as fertilizer.

Does anyone know what blueing salts are?  And does anyone know which
fertilizer can be used for blueing  ( possibly the same question )?

I recently bought some aluminum sulphate at the garden nursery for use in
disolving a broken tap out of a piece of aluminum.  And this set me
thinking.

				Cheers,

---

From: [email-masked]
Date: 20 Sep 1996 14:33:07 GMT

>   Jeffrey Prothero <[email-masked]> writes:

Bluing in a hot salt system generally involves three chemicals that are closley related. If fertilizer was used in your friends system it 
was ammonia based, probably ammonium hydroxise, ammonium nitrate and ammonium nitrite.

You can use sodium hydroxide (caustic soda) and its nitrate and nitrite just as easily and with no difference i the bluing result. The 
Hydroxide is used to make a water solution that has a boiling point that is high enough for proper blueing as opposed to rusting. The 
idea is to get the temperature up to about 295 degrees F though some steels require that the temperature then be raised to 310 + 
degrees to avoid a purplish result.  By putting the appropriate amount of caustic soda in the water you get a solution that boils at the 
temperature you want and controlling the temperature is then easy. If it is boiling the temperature is right, if it isn't boiling it's too cold.

Of course this doesn't eliminate a thermometer. After a while the boiling solution loses water to steam and the density goes up along 
with the temperature. This can be used to raise the temperature as described above but usually it is better to use two separat tanks 
at the two temperatures. A warning here, adding water to the solution to control the temperature/solution density when it is boiling is 
a tricky task because the pure water wants to flash into steam and that can cause hot caustic soda to spray all over the place. 
Another warning is that the steam and salts should be kept out of your shop unless you want the equivalent of an ocean spray all 
over your nice iron machines which will rust like you wouldn't believe.

The other two chemicals, the nitrate and nitrite are what get the bluing process going. I am sorry that I don't have the exact 
proportions handy here at work but they need only be added once. After bluing starts to work in a solution int seems to keep going 
no matter what and so the chemicals are not used up in any ordinary sense of the word. Cool solution can be kept in plastic buckets 
(not steel of course) and re-used many times. Eventually,however, crud starts to muddy the waters and it is then a good idea to 
make a fresh batch. 

Any kind of metalic impurity such as copper, zinc, aluminum etc. will destroy the bath. Copper sulphate may be found in tap water, 
whether from copper pipes or municipal efforts to control algae. Alumimum from some gun parts is equally bad. Even failing to use 
buffing wheels that are exclusively used on steel will risk poor results so no polishing the brass fittings on the boat before polishing 
your gun. Also if you make the mistake of putting aluminum gun parts in the bath they will be eaten up in a hurry so be warned. 
Finally old double barreled shotguns were often held together with the ribs using soft solder. This too will be at risk due to the high 
heat involved and you could end up with the barrels and rib pointing in four different directions! Soldering them back together is easy 
though if you have twelve hands and 20 years experience.

Good luck.

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From: [email-masked] (Skarsaune)
Date: 21 Sep 1996 06:17:54 -0400

Check the new issue of HSM for an article on hot bluing, also.
Chuck

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From: Jeffrey Prothero <[email-masked]>
Date: Sat, 21 Sep 1996 05:53:07 -0700

That was another reason why I was wondering mhat blueing salts are.
				Cheers,

---

From: [email-masked]
Date: 21 Sep 1996 15:20:52 GMT

Jeff, I used to do some gun bluing using a mixture of sodium hydroxide (lye) and
ammonium sulphate (fertilizer).  Temperature control for bluing is critical, the amount of 
lye in the solution is used to control the temperature.  This solution produced a very
dense hard finish, but.... When mixing the solution, much strong ammonia gas is produced.
Do it outdoors and don't get downwind.

John

---

From: [email-masked] (Bruce Conner)
Date: 22 Sep 1996 01:50:00 GMT

Here is some information from the Dixie Gun Works catalog on a simple
blueing solution using (guess what?) fertilizer!

Mix one part sodium nitrate, two parts caustic soda, and two parts water
by volume. Mix and boil ONLY in a steel or enamelled container, NEVER in
aluminum.  Boil the parts at 280 to 315 degrees F until the desired color
is obtained.  

Looks as if the salts raise the boiling point a bit there. :')  Also, be
sure to degrease your parts completely and all that.  Be careful, this
solution sounds nasty if you were to get any on you.

Bruce Conner
[email-masked]

---

From: Jeffrey Prothero <[email-masked]>
Date: Sun, 22 Sep 1996 19:22:11 -0700

> Do it outdoors and don't get downwind.

I called my friend and he said that he used Sodium Nitrate ( sold as
fertilizer for roses ) and Lye.      That gives a very black finish.
I will do a bit of experimenting and report the results.

					Cheers,

---

From: Jeffrey Prothero <[email-masked]>
Date: Sun, 22 Sep 1996 19:42:56 -0700

> solution sounds nasty if you were to get any on you.

I called my friend today and found out that is what he used.  He didn't
give me any idea of what ratios, so thanks for that information.

					Cheers,

---

From: [email-masked] (Russ Kepler)
Date: Sat, 21 Sep 1996 19:46:44 GMT

Reposting article removed by rogue canceller.

In article <[email-masked]>,
>fertilizer can be used for blueing  ( possibly the same question )?

The most easily obtained chemicals are sodium hydroxide, sodium
nitrate and sodium nitrite.  Industrial grade chemicals are fine,
even prilled sodium nitrate fertilizer will work.  The percentages
are 50%, 25% and 25%, adding to water until the boiling point hits
(as another poster said) something like 295 degF.

Bluing can be a hit and miss proposition, if you don't have good
temperature control, a good prewash for degreasing and some
experience.  Most simply steels (10xx, 11xx and 12xx) will blue
nicely, even 12L14 comes out nice.  Chrome-Moly steels blue well as
well (naturally, with all those 4130 barrels out there but steels
with much nickle, or too much chromium will either not blue or blue
with some funny colors.  If you run into one of these (a post-64
model 94, as an example) you need to play with the bath time and
temperature to get a good blue.  Most time about 20 minutes at
295 degF will give a good blue.

Don't blue something with want to have low friction - iron oxide is
not known for low friction.  Aluminum will last a couple of seconds
in a bath, and copper will "kill" the salts, making for an expensive
replacement.  A wrapping of electrical tape will protect a surface
>from  bluing, as well as some paints.  Keep a bottle of white vinegar
around to neutralize the NaOH.  NaOH at 300 degF on exposed skin
really, really hurts.  If the "blue" is purple toss it back in and 
raise the temperature 5 degF.  Cast iron will blue eventually - 
leave it in the bath for a few cycles.  Boil what you pull from the
bath in water to remove the salts at least 10 minutes if there are
threads connecting anything.  Use a polarized oil after removing the 
clean blue metal, hang up hot to dry remaining water.

Don't get me started on phosphating.

-- 
Russ Kepler							[email-masked]

                    Please Don't Feed the Engineers

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From: [email-masked]
Date: 21 Sep 1996 15:43:28 GMT

>disolving a broken tap out of a piece of aluminum.  And this set me

Pretty good artlicle on bluing in the Sept/Oct 1996 issue of Home Shop Machinist.

It say that the salts used were called Oxynate No. 7 from Brownell's Inc.
They also have a pamphlet on "Bluing instructions and Supplies"

For catalog:

Brownell's Inc.
200 S. Front St.
Montezuma, IA 50171 

Randy

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From: [email-masked] (Steve Rayner)
Date: Tue, 24 Sep 1996 04:15:33 GMT

No need to get that toxic!  I have been using a simple, safe, & cheap 
blackening solution for years.  Use 3 grams, or a bit more of sodium 
theosulphate ( From your friendly darkroom supply firm ), disolved in a 
liter of water.  Heat to 200 F. & dip the object until it is the desired 
shade.  You may have to scratch brush it a few times, especially if the 
solution is too strong.  The first objects I used this on, have been 
rattling around in my toolbox for years, and the finish is still good.  
In fact, I used ordinary Kodak acid fixer, which was too strong, but it 
worked!

In a previous article, [email-masked] (Jeffrey Prothero) says:

>rnetmci.com!in2.uu.net!netnews.nwnet.net!news.u.washington.edu!saul2.u.washington.edu!jsp
>From: Jeffrey Prothero <[email-masked]>
>Newsgroups: rec.crafts.metalworking
>Subject: Re: Blueing steel
>Date: Sun, 22 Sep 1996 19:22:11 -0700
>Organization: University of Washington
>Lines: 19
>Message-ID: <[email-masked]>
>References: <[email-masked]> <[email-masked]>
>NNTP-Posting-Host: saul2.u.washington.edu
>Mime-Version: 1.0
>Content-Type: TEXT/PLAIN; charset=US-ASCII
>NNTP-Posting-User: jsp
>In-Reply-To: <[email-masked]>
>
>
>

-- 
Steve.

**************  BE ALERT, THE WORLD NEEDS MORE LERTS ************************

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From: [email-masked] (Ray Spinhirne)
Date: 25 Sep 1996 03:18:58 GMT

Jeffrey Prothero ([email-masked]) wrote:
: Many years ago a friend reblued the barrel of my .22 rifle in a tank of
: boiling solution of some salt.  This is of course the usual way blueing is
: done.  However the salts that he used were not sold for use in blueing.
: They were sold as fertilizer.

: Does anyone know what blueing salts are?  And does anyone know which
: fertilizer can be used for blueing  ( possibly the same question )?

: I recently bought some aluminum sulphate at the garden nursery for use in
: disolving a broken tap out of a piece of aluminum.  And this set me
: thinking.

: 				Cheers,

There is an article in the current HSM which cover this topic.  It does
not give a formula for the solution (recommending instead a commercial
source), but the rest of the article does a pretty good job of explaining
the process, and the danger involved.

---

From: Van Baker <[email-masked]>
Date: 25 Sep 1996 16:04:22 GMT

Speaking of the HSM article, does anyone know a source for a 10-12" pipe 
burner, or better yet plans for making one to burn on propane?

Thanks!

---

From: [email-masked] (Russ Kepler)
Date: Wed, 25 Sep 1996 19:47:26 GMT

In article <[email-masked]>,
>burner, or better yet plans for making one to burn on propane?

I made one from an old LP manifold from a gas barbeque that I'd
upgraded to home (natural) gas.  I just used 1" black iron pipe with
1/8" holes drilled every .200 inches.  Works fine in the short length
I needed (about 12").

---

From: [email-masked] (Charles Gallo)
Date: 25 Sep 96 21:12:31 -0700

Van,
	Call Brownells'.  They are the people to get the salts from, and 
they sell the pipe burners, tanks and everything else too.

Brownells
200 South Front Street
Montezuma IA 50171
(515)623-5401

No connection with them except has happy customer