BLACK CHROMATE KIT 

PART NUMBER:- A865

CASWELL's Black Chromate Kit is a single dip chromate process consisting of two components, Black Chromate A and Black Chromate B.

This system can be used over CASWELL Zinc and Copy Cad Plating Systems and will give a consistent and uniform black color.

The Black Chromate A solution contains chromic acid, which is a corrosive acid. Make sure to use proper personal protection. Rubber gloves, protective eye gear and NIOSH approved respirator are recommended.

Proper local ventilation is also recommended.

Mixing Instructions - be sure to mix in the following fashion to prevent acid splashing

1. In a 10 Litre or larger plastic tank, add 3.3 Litres distilled water at room temperature

2. Add the contents of the bottle of Black Chromate A

3. Add the contents of the bottle of Black Chromate B

Usage - Solution temperature should be 21-32 deg C for best results.

1. Rinse the part in distilled water after plating.

2. Hang the part from some copper wire and dip into the solution. Parts should be immersed for approx. 30-120 seconds. You may have to experiment with the time to get the right color.

3. Rinse the part in distilled water

4. Allow to air dry or dry with a hair dryer (air temp not to exceed 70 deg C)

Makes 3.5 Litres of mixed chromate.

N.B. ADD chromate solutions to water,  DO NOT add water to chromate solution, it will spit and splash acid.

Instructions for using the black chromate on previously plated bolts are as follows. 

This only works if thee is sufficient zinc plating on the parts. If it doesn't work the parts will most likely need to be replated.

1. Degrease parts, a scrub with soapy water would probably be sufficient.
2. Rinse parts in clean water.
3. Dip parts in 3% solution of sulphuric acid for 2 seconds ONLY. 
4. There should be a slight effervescence from the parts, immediately remove and rinse in clean water.
5. Dip the parts in the mixed black chromate solution for the prescribed time on the label.
6. Rinse again for a short time to rinse of any excess black chromate.
7. Either allow to air dry or use a gentle heat, no more than 70 deg C, to complete the process.

See below for current MSDS