Friday, May 1, 2009

Etching with Ferric Nitrate Follow up

Thea Clark, Habeas Corpus Boteh Brooch, etched with ferric nitrate

Here is a follow up to etching with ferric nitrate. Sandra Noble Goss uses 4oo ml distilled water to 300g ferric nitrate. She finds it etches silver in 2 to 7 hours depending on age of the solution. She also finds the PNP BLue resist holds up  to this. Agitation can help too. 
She has had better luck than I 've had, or perhaps I am just not patient enough. In my experiments I was etching a very thin layer 2 hours hadn't begun to do it with a new solution and the resist was not holding up. The crystals absorb moisture as soon as they are exposed to air and rapidly become ineffective. I truly wish this friendly substance would work consistently, but it isn't the nature of the beast. I have resorted to a dilution of nitric acid for silver, sold by Rio Grande. I have access to a fume hood with excellent ventilation at the art center were I teach. Using this in one's own studio, or home is a matter of personal choice. Everyone should do their homework about the hazards and clean up protocol, before making the decision. I have decided against it.


Henry said...

I think ferric nitrate and ntric acid are the same thing.

Thea Clark said...

Hi Henry,
Ferric Nitrate is Fe(NO3)3, created by treating iron metal or iron oxides with nitric acid.

Nitric acid HNO3, on the other hand is a highly corrosive acid. They are not the same thing. And while both are handled with caution, nitric acid is potentially far more hazardous.