Disposing of Iron (III) Nitrate and etching

[TPMW]

Dear all,

Hi! First post from here. I was wondering how to dispose safely of Iron (III) Nitrate solution from etching. Can it be diluted and put down the sink or does it need to be sent to a special place?

Is there anything else safer to use or easier to dispose? I have a slow cooker and measure out in weight 4:1 water:nitrate. Is this the best ratio?

Does anyone have any hints and tips on using pcb paper for printing with a laser printer and ironing onto the silver?

I seem to get a better etch with a cold solution for 24hrs than with a hot tank for 2 hours as bubbles form in the hot solution. Any advice on this too?

many thanks one and all,

Ian...

[ps_bond]

Hi Ian -

No, you can't put it down the sink - it's fairly noxious & obnoxious stuff. I'd probably neutralise with bicarb or similar, evaporating to dry and contacting your local council for advice on which tips accept hazchem waste - although the disposal recommendations on the MSDS say only to keep it in a container.

I've seen 2:1 nitrate:water by weight suggested - that would make your solution quite slow by comparison, but a slower etch can be better (cleaner & less undercutting) than faster.

What sort of thing are you looking for? PnP Blue is pretty tolerant - so long as the surface is clean, with a slight tooth (Scotchbrite the metal, for example) and ideally pre-heated. Touch up any duff areas with a permanent marker (although ISTR some people maybe had trouble with permanent markers & nitrate, they are fine for ferric chloride).

The bubbles on the object block the access of the etching solution to the metal, so need to be kept off - in commercial systems, a stream of bubble is flowed through the tank - a similar thing can be done with an aquarium air pump, but the airstones will dissolve (I'd suggest using google for alternatives); the traditional way of keeping bubbles off is to brush the object in the etch with a feather.

Forgot to add this link - http://www.ganoksin.com/borisat/nenam/photocopy_transfer_etch.htm

HTH!

[TPMW]

Peter hi,

My thanks for your help with this enquirey and my apologies for the late reply. I am building a workshop which I hope in time to bring up to that of a university standard. Etching is a new technique to me so I really appreciate your advice.

Do you know what any kind of wieght ratio with bicarb yuo would use to neutralise the nitrate? Or, what else can be used? And after that stage, how you would dispose of the neutralised solution? I will also contact the council to enquire about hazchem waste.
I am putting a filtration system in place to re-use the iron (III) nitrate and filter out the gunk at the bottom. Do you know if the strength of the solution gets weaker if I were to do this?
To keep it as safe and used in small quantities, I am using a (wide) slow cooker with water only in it and tupawear containers with a shallow solution of the nitrate and lid on both to reduce fumes. Would you recommend anything else before purchsing a dearer tank designed for etching?

Many thanks again and my best,

Ian at The Precious metals Workshop