Etching of copper and its alloys (brass, brown) na matowo
• W 50 Dissolve cm3 of water 2 g table salt and 1 g of zinc sulfate, add 214 cm3 of concentrated nitric acid i 108 cm3 of concentrated sulfuric acid. Digest for 5…10 min at room temperature.
• The solution with the composition works similarly: 145 cm3 of concentrated nitric acid, 55 cm3 of concentrated sulfuric acid, 2 g of table salt, 3 g of zinc sulfate.
Bright etching of copper and its alloys.
Immerse the item for a very short time (1..3 s) for baths at room temperature and composition: 750 cm3 of concentrated nitric acid, 270 cm3 of concentrated sulfuric acid, 20 g table salt and 25 g of soot. Rinse vigorously with water immediately after removal. Extending the digestion time or delayed rinsing causes stains on the surface. They can be removed by etching again, made according to the recipe.
Silver matte etching
• Cook items for 10…15 min in solution 800 g of anhydrous potassium carbonate, 80 g borax and 33 g of sodium nitrate. Rinse with plain first, and the last time – distilled water.
• You can also use the solution in the same way: 250 g of anhydrous potassium carbonate, 240 g borax and 100 g of potassium nitrate v 3 dm3 of water.
White etching of silver.
Immerse items in a boiling bath with the composition: 10 g of acidic potassium tartrate, 20 g table salt and 1000 cm3 of water, for the time needed to obtain the desired shade of the surface. Rinse with water, then with water with the addition of a few cubic centimeters of ammonia on 1000 cm3 and again with only water.
Matt etching of zinc sheet.
Dissolve 5 g table salt and 5 g of zinc sulfate in the mixture 730 cm3 of concentrated nitric acid i 270 cm3 of concentrated sulfuric acid. Digest for a few seconds at room temperature. Rinse very carefully and dry. A zinc sheet etched in this way can be used to prepare printing plates using the photoprint method (zincograph).
Interesting decorative effects can be obtained, by etching the entire surface of the metal matte, and then covering some parts of it with protective varnish (e.g.. asphalt) and bright etching again. After digestion is complete, the varnish is washed off with gasoline or turpentine.