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CLEANING NONFERROUS METAL AFTER HEATING / ANNEALING

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Metals such as copper and brass are cleaned in a heated pickling bath (dilute sulphuric acid), after annealing and when they are cold. This removes the oxide that forms on its surface, during heating. The metal should be handled with nonferrous tongs (ferrous tongs will contaminate the acid solution). The pickling solution is composed of 1 part acid and 9 parts water. Aluminium must not be pickled. Heating the acid pickle solution, has the advantage that it will remove flux after soldering and clean the surface of the metal faster. Pickling baths are supplied with a strong lid, which must be placed in position.

FOLLOW ALL LEGAL GUIDELINES REGARDING THE HANDLING AND STORAGE OF ACID AND PICKLING.
 
After pickling, the annealed metal is washed with water, cleaned with pumice powder and allowed to dry. Failing to follow this procedure properly, will mean that oxide / impurities on the surface of the metal, will be ‘hammered’ into the surface, when shaping and forming the material.
 
 
 
 
Pumice is a rock and when ground to a powder, it becomes a natural, fine, abrasive. A damp pad is used to rub the pumice over the surface of the metal, cleaning it further. Finish by washing the metal in water.  
 
IMPORTANT: When mixing the pickling solution, extreme care is required. Acid is added very slowly to the water. WATER SHOULD NEVER TO ADDED TO CONCENTRATED ACID AS THIS IS POTENTIALLY VERY DANGEROUS). The pickling bath should be located near a sink with a water supply.
 
 
 
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