ENAX – Cold Electrolytic cleaner
This cleaner should be used only for copper and copper alloys. It should not be used for steel. The articles are made cathodes in this treatment. It is intended as a final cleaner and should be preceded by cleaning in the USEX metal cleaner. After every cleaning operation, the articles must be rinsed in clean cold water, preferably running water. After the articles are treated in this cleaner they should be put through the following dips.
(a) 10% solution of sulphuric acid if the work is to be plated in an acidic solution such as nickel. It is swilled before placing it in the plating vat.
(b) If the work is to be plated in an alkaline solution such as cyanide copper, zinc or tin, then it is put through a cyanide dip and swilled before placing in the plating solution.
It is important to remember that the non ferrous articles or sling wire that may accidentally fall in the tank, will contaminate the cleaner solution. They slowly dissolve in the solution and when the cleaning is in progress, they become anodic and plate out on the articles to be cleaned. The Necessity of maintaining the bath free from metallic contamination cannot be over emphasized.
EQUIPMENT
A welded steel tank with wooden capping and three work rods with insulators are required. An adequate source of direct current at 6 volts is essential. A knife switch should be fitted near the tank. Lead lined, tinned or galvanized tanks should NOT be used. The middle rod is used as the work rod. The other two rods are connected to, the positive lead of the supply and have clean mild steel sheets hung as anodes. The cleaner is used at room temperature:1: and no heating equipment is necessary.
CONCENTRATION
- ENAX metal cleaner – 125 gms./l
- Voltage – 6 Volts.
- Current Density – 20 to 40 Amps. per sq. ft.
- Immersion – 2 to 3 minutes
PREPARATION
The tank is filled with clean cold soft water to 2/3 its working capacity and the appropriate quantity of salts are thoroughly dissolved. The correct level of the bath is then obtained by adding more water.
DENSITY AND MAINTENANCE
The density of the fresh solution should be about 8° -9° Baume or 12° -13° Twaddell. On usage, the density may increase a little. This should be disregarded and the losses by ‘drag out’ etc. should be made up by regular additions of small quantities of salts. Floating films of grease or oil should be skimmed off the surface of the bath every now and then. It is advisable to discard a very dirty solution and prepare a fresh one.
OPERATIONS
(1) Following a treatment in USEX metal cleaner and thorough swilling in clean water, the work is placed in the ENAX cleaner solution for 2 to 3 minutes as cathode in the circuit.
(2) The treated work is withdrawn, swilled thoroughly and placed in the acid dip, swilled and placed in the acidic plating solution such as nickel.
(3) If it is to be plated in an alkaline. or cyanide solution a further dip in sodium cyanide solution should be given followed by a swill before placing the. work in the plating bath.
ACID DIP
is prepared in a rubber lined tank or a glazed earthenware vessel. Pure sulphuric acid should be added to cold water at the rate of 100 grams per litre. The density of the solution should be 8°Baume or 12°Twaddell.
CYANIDE DIP
is prepared in a plain steel tank or earthenware vessel by dissolving in water pure sodium cyanide at the rate of 2S to 38 grams per litre. It is used cold.
[hr top]