Anybody remember the name of that chemical that permanently stains brass black? No, I don't want to camouflage my brass, but I was thinking that with an inkpad, some "chemical X" and a rubber stamp set I could create groups of brass and keep them segregated throughout the shooting, cleaning and reloading process. Dean Grennell mentioned marking brass by dipping in this stuff in one of his reloading books. Careful use of a stamp would be more useful. I have a lot of brass.

Paul

Well, this is a bit long, but since it is exactly what you are looking for (and then some!), I'll post it.

This will tell you how to make brass black, and a lot of other colours too.

jpb

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The Coloring of Brass
by Royce W. Beal
written on 17 March 1995 specifically for the readers
of the rec.guns newsgroup.
questions should be directed to me at SLQZ4@CC.USU.EDU

Read this entire essay before attempting any one
treatment. If you choose to just "cut and paste" part
of this, please make sure you get the safety instructions
and warnings after the recipes. Under no circumstances
do I consider myself liable for any accidents which occur
while using any of these chemicals. Also, I do not consider
myself an expert in this field and am still doing research
for the FAQ. This will be a temporary article. Because I
am still experimenting, I cannot vouch for all of these
colors.

Concentrations and conditions DO matter. (Concentration
is more important than actual volume, so if you want to
use less, make sure that you use proportionately less of
each ingredient) If you want good results follow the
recipes closely. Above all it is important that the brass
surfaces be clean. This means an extra hour or so in the
tumbler for the cases and then touch them only sparingly.

I have tried to collate recipes which will require the
acquisition of the more common chemicals. I have also tried
to steer clear of the really hazardous arsenic and cyanide
salts (which you probably can't get anyway) If you feel
that you've been cheated by this, please refer to the
references section of this report and find the books for
yourself in any well stocked library.

It is my understanding that these are all surface
coatings and should not damage or weaken the brass.
Obviously you will want to do this treatment with unprimed
brass. DO NOT USE METAL UTENSILS (OK maybe stainless steel)
Glass or Plastic containers are the preference. If you are
really worried about what this is going to do to your brass,
refer again to the reference section below.

TIFFANY GREEN
Copper Sulfate.................8 ounces
Ammonium Chloride..............4 ounces
Sodium Chloride................4 ounces
Zinc Chloride..................1 ounce
Acetic Acid....................2 ounces
Water..........................1 gallon

VERDE
Copper Nitrate.................16 ounces
Ammonium Chloride..............4 ounces
Acetic Acid....................1 quart
Water..........................1 gallon

GREEN
Iron (ferric) Nitrate.........2 ounces ( Fe(III)(NO3)3)
Sodium Hyposulphite............8 ounces
Water..........................1 gallon
(use at boiling temperature, brass can be immersed
or the solution may be "painted" on)

HARDWARE GREEN
Iron (ferric) Nitrate..........1 ounce (Fe(III)(NO3)3)
Sodium Thiosulfate.............6 ounces
Water..........................1 gallon
(use at 160F)

RED
Iron (ferric) Nitrate..........6 ounces (Fe(III)(NO3)3)
Sodium hyposulphite............6 ounces
Water..........................1 gallon
(use at 170F will speed up this reaction)

BLUE
Sodium Hyposulphite............8 ounces
Lead Acetate...................4 ounces
Water..........................1 gallon
(use at boiling temperature)
or
Lead Acetate...................2 to 4 ounces
Sodium Thiosulfate.............8 ounces
Acetic Acid....................4 ounces
Water..........................1 gallon
(use at 180F. This color will change if
not lacquered [DO NOT LACQUER FIREARM CARTRIDGES]
Take your chances with the color change.)

BLUE BLACK
Copper Carbonate...............1 pound
Ammonium Hydroxide.............1 quart
Water..........................3 quarts
(Add the water after the carbonate and hydroxide
have been mixed. There must be excess Copper
Carbonate. Use at 175F. This color can be fixed
(made more permanent) by quickly dipping in a 2.5%
Sodium Hydroxide solution.)

BLACK
Ammonium Hydrosulfide...........2.25 ounces
Potassium sulfide...............1 ounce
Water...........................1 gallon
(use at room temperature or COOLER for best results)

BROWN
Potassium Chlorate..............5.5 ounces
Nickel Sulfate..................2.75 ounces
Copper Sulfate..................24 ounces
Water...........................1 gallon
(use at boiling temperature)

SAFETY
1. NEVER taste any of these chemicals.
2. Keep very far out of the reach of children.
3. Most Nitrates are good oxidizing agents and
should not be stored with anything flammable.
4. Acetic Acid has a VERY strong pungent odor.
Use in well ventilated areas. This acid can
be airborne in vapor form. If you feel that
you have breathed enough of it to feel
uncomfortable, leave the area and drink a
carbonated soft drink. "Have a Coke" Do not
underestimate this chemical.
5. Many of these chemicals may stain your skin or
clothing. Wear rubber gloves and protective
clothing including glasses of some sort.
6. Steam can cause serious burns. Solutions of salts
can actually exceed the boiling point of water.
The steam from these solutions can be very dangerous.
BE CAREFUL WITH STEAM AND BOILING SOLUTIONS.
7. Feel free to change concentrations for experimentation
purposes but do not change the ingredients in any
one recipe.
8. Always be fully awake and alert around chemicals.

CONVERSIONS AND INTERPRETATIONS
Ounces are assumably troy ounces, even when dealing
with liquids or solutions. Do not use fluid ounces.
1 ounce = 31.103 grams = 480 grains
1 quart = 0.25 gallon = 946.4 mL
1 gallon = 3.785 L

REFERENCES

Meyer, Walter R. title Plating and Finishing Guidebook
ninth edition - 1940 pp.72-75 (cited)

Metal Finishing Guidebook twenty-eighth edition - 1960
article by Hall, Nathaniel title Coloring of Metals pp. 477-479
(cited)

Krause, Hugo title Metal Coloring and Finishing (not cited)

Hiorns, A. H. title Metal Coloring (not cited)

Field, S and Bonney, S.R. title Chemical Coloring of Meta
ls (not cited)
-Royce

**********************************************************************
Message 13
Date Fri, 29 Mar 2002 101407 -1000
From Reese <reeza@hawaii.rr.com>
Subject Re Blacking brass

At 0835 AM 3/29/2002 -0500, Roy Wilson wrote
>On Fri, 29 Mar 2002 050432 -0800, Keith Whaley wrote
>
>>I wouldn't call that a "common household chemical," but...
>
> No, he's right. There is some kitchen chemical that will do it,
>I've seen it before. Still too much blood in my caffiene stream to
>remember what it was now, though.
>
> Ammonia fumes, maybe?

Manual of Formulas, ISBN 1-55918-036-6 (reprinted by Lindsay)
reports one formula (of four) that happens to include Ammonia
water, it also includes some other stuff

#4
Ammonia Water 16 cc
Ammonium hydroxide, strong 16 cc
Water 16 cc
Sodium Carbonate 1 gm

Add to the above, copper carbonate powder
until no more of the powder will dissolve.
Immerse the brass article in the heated
solution.

It also reports some formulas for green, brown, steel gray,
silver, and violet. Not to mention, solutions for some other
metals.

Reese
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It's called Brass Black, it doesn't work very well on tarnished or dirty brass. Clean the brass first with steel wool to make the chemicals color better.

Brass Black? Now why didn't I think of that? The mixing of chemicals is a bit intimidating for me. I shied away from chemistry even in high school. If I can find some already mixed Brass Black I would prefer to go with that. Boiling the brass in alcohol will remove any oil and not leave a residue. Thanks guys. That was very interesting reading.

Paul