BLACK COLORING AGENT

ALBLAC # 619

Description

This is to color steel and low alloy, and you can have

beautifuly colored metal simply by dipping. The following

chemical can be used for this method.

ALBLAC # 619 lump, flake or powder.

This method meets with the following specification.

U.S. Army Specification

            MIL - C - 13924 A (1956) CLASS2

            MIL - P - 12011 (1952) FINISH NO. WW 04

            GRADE 2 AND - 10398

APPLICATION

The surface to be treated must be clean.

Sand or shot blasted surface will be rough and acid wash

primed surface will be dull black. The surface must fully

polished after sand blasting or acid wash. Cold treated

surface (pressed or pulled) may affect the color to be

lighter.

Good coloring depends on surface preparation.

Coloring Black by Oxidization. (Fe₃O₄)

1.   Preparation of treating tank

Fill a half of the tank with water and add ALBLAC#619 to

the water slowly. Start heating the tank when added

ALBLAC is over half the required quantity, and keep adding

small quantity of #619 and water. When ALBLAC#619 is

dissolved fully and temperature goes up to boil at 141+2^oC,

you can start coloring by dipping. When the boiling temperature

is higher than 141^oC, adjust the temperature by adding some

water and when the boiling temperature is lower than 141+2^oC,

adjust it by adding more colorant or vaporizing water.

Treating Tank:   ALBLAC#619 1000g

                      WATER         700g

The temperature of processed liquid will be 137^oC. Dip the

objective after heating it in a mild alkaline liquid (1-2

minutes). It will take about 20 minutes to finish coloring but

it may take 30 minutes in some cases.

Coloring time depends on the kinds of material, and grades of

surface preparation, It is good to keep the tank temperature

between 137^oC and 145^oC. If the temperature is over 150^oC,

redish brown sediment may stick to the objective or rate of

oxidization can be reduced rapidly.

After dipping, take the objective from the tank, wash with hot

water and remove alkali by rinsing with clean water. (0

minute washing is proper and long time washing may corrode

the objective of high carbon steel), And then wash the

objective with mild chromium acid and dry it.

2.   Mild chromium acid wash

This is to neutralize the little alkali left on the objective and

to improve the anti-corrosion of the film.

Composition of chromium acid :

                                            anhydrous chromium acid 2.5g

                                            water        1,000ml

To keep the concentrated degree at PH2-3, add proper

quantity of anhydrous chromium acid. Treating temperature is to

be between 65^oC and 88^oC, and dipping time is 30 to 40 seconds.

After this treatment, dry the objective with compressed air,

hot air or drying oven. Drying time should be within 5 minutes.

3. Finishing Treatment

To keep the film from corrosion and aesthetic purpose, you

may use rust preventive oil, varnish or a clear lacquer.

4. Procedure

Degrease - wash with water - wash with acid - wash with

    (Sand or shot blasted)

water - coloring - wash with water - wash with chromium

acid - oiling or coating