Ferric Chloride

[theresa]

Has anyone used this chemical to etch silver?
I want to try etching but am very wary of acids.
Thanks

[ps_bond]

It'll work for a short while, but because it forms silver chloride (which is insoluble) it won't etch the piece for very long. Ferric nitrate is a "better" bet, but they're all to be treated the same as acids - the dissociation of the nitrate ion (in ferric nitrate) is what does the actual etching, same as in nitric acid.

You can also electro-etch silver using silver nitrate as the etchant.
https://carolholaday.files.wordpress..._rectifier.pdf

[enigma]

I tried it once instead of ferric nitrate and found it useless, gone back to nitrate now.

[theresa]

Thanks Peter. When I did a short course at West Dean they covered this process. I don't think I could set up the operation in my small studio, so will probably give it a miss for the time being.

It'll work for a short while, but because it forms silver chloride (which is insoluble) it won't etch the piece for very long. Ferric nitrate is a "better" bet, but they're all to be treated the same as acids - the dissociation of the nitrate ion (in ferric nitrate) is what does the actual etching, same as in nitric acid.

You can also electro-etch silver using silver nitrate as the etchant.
https://carolholaday.files.wordpress..._rectifier.pdf

[theresa]

I have now investigated salt water engraving and I think this is something I could manage!

[ps_bond]

Same difference - it doesn't do silver very well because of the chloride formation. Same setup but with silver nitrate and you can...

[Ralph G]

Solubility of Silver Chloride : 0,0014g/L at 20°C
Solubility of Silver Nitrate : 2160 g/L at 20°C

This should tell you something. HUGE difference. In etching silver there is unfortunately no good way around the nitrate.
I am most happy using electrolytic etching with 3% diluted nitric. Thats quite safe (classified only as an "irritant" compared to the hazard of conc nitric) and gives excellent results. If you dont want to deal with nitric acid at all you can replace it with a 10% solution of silvernitrate as ps bond stated. But silvernitrate is much more expensive than nitric.
Since silver is constantly deposited at the cathode you can approximately dissolve about 600g of sterling per L before there is too much copper in solution to affect things. Thats a LOT of etchings. The deposited silver can simply filtered out of the solution,washed, collected and remelted. So its an economic process as well.

[ajda]

I am most happy using electrolytic etching with 3% diluted nitric.

What exactly is the law on nitric acid now? Can you buy it at all without a licence?
Alan

[trialuser]

A business user can buy it without an epp licence.
Private individuals can buy it at up to 3% conc.
Private individuals with an epp licence can buy what it says on their licence, eg 2.5L of 70%.
An epp licence is easy to get as long as you haven't been too naughty in the past, costs £39.50 for 3 years.
The offence is not just to 'buy', it's also possess (so existing stock of private individuals), import and to supply a non licence holder.

[ajda]

Thanks for the clarification.
Alan