Workshop on Etching with Linda Darty
Reproduced with permission from the Newsletter of Enamel Guild North East, USA
The two-day workshop with Linda was both rewarding and intensive. We started the class by learning about three acids used for etching on metal: Nitric Acid, Ferric Nitrate and Ferric Chloride.
Nitric Acid can be used to etch both silver and copper. Of all three acids Nitric is the most hazardous, does not bite the metal as cleanly and fewer resists can be used because it is so volatile, bubbling and lifting resists during the etching process.
Ferric Nitrate is safer to use, can etch on copper and silver, bites the metal more cleanly and works well with oil based paint pens and heat transfer paper (PNP). Ferric Nitrate is basically nitric acid which contains iron and is neutralized with baking soda for clean up. It etches more slowly than Nitric Acid. The recipe to mix the acid is 1 pint of hot water poured over 500 grams of crystals. Wait for them to dissolve.