How to Etch a Brass Shell Casing Without Acid: Update: Disposal of the Etching Solution

In my previous post last week, I told you how to Etch without using acids, by utilising a solution of copper sulphate crystals, table salt and tap water, however I forgot to explain that one of the benefits of this method is that it is relatively easy to dispose of the etching solution after use.

For the original post follow this link:

http://trenchartswordsintoploughshares.blogspot.co.uk/2012/11/how-to-etch-brass-shell-casing-without.html

My trusty soda crystals are always by my side when etching shell casings, to act as a neutralising agent between periods in the etching bath

The solution itself will etch many shell casings before the need for disposal, by which point it will have turned brown in colour. Although I like a slow etch from the solution so that I have full control over the process, by the time that the solution turns brown, it will take too long to etch, even for me. At this point, the Bordeaux Technique (as this method is commonly referred to as) comes into its own when being utilised in a domestic setting without the support of a studio system and the ability for specialised disposal of chemicals, costing only the price of ordinary soda crystals available from supermarkets (I bought my last packet in a £1 shop)!

Simply, all that is needed is for the old solution to be poured away and the solids put into a plastic bag and put into the bin. This is the advice given by Hawthorn Printmaker Supplies where I purchased my Copper Sulphate Crystals from (www.hawthornprintmaker.co.uk), however I am a little more cautious. As the neutralising agent for the Copper Sulphate is the above mentioned soda crystals, I throw a bag in to the solution to dissolve before I pour it away, just to be on the safe side, and for the sake of £1, it gives me peace of mind without breaking the bank! However, if neat Copper Sulphate is to be disposed of, it must always be neutralised with soda crystals first, as it is hazardous to marine life!

As I do not etch every week, I decant my solution into 5Ltr water bottles. This is where you will notice the sediments settle in the bottom between etches. It becomes a crystalline lump in the bottom of the bottles, which, if you are not expecting it, could cause concern about the efficacy of the solution.

It should also be noted by printmakers, that this mordant will etch aluminium, zinc (which does not require the addition of salt in the solution), copper, and with time, steel plates. Although the postings have been specifically about etching brass shell casings, the general principals will work for etching plates for the purpose of intaglio processes.

If any clarification or advice is needed, I am happy to reply, and you are also welcome just to make comment.

Large shell casing etched with Copper Sulphate and Table Salt solution (Bordeaux Etching Technique)