Wednesday, February 23, 2011

An Electrolytic Etching Tip


Anybody who has done any kind of etching always eventually encounters the problem of what to do with all the spent solution. In electrolytic etching this is somewhat less of a problem because the solution isn't toxic or corrosive, but you still can't just pour it down the drain. I've recently discovered a simple trick that allows me to indefinitely re-use my saltwater solution. When I'm done with my etching, I simply filter the solution through a coffee filter. The filter catches most of the sludgy copper compound from the water and I'm left with nearly clear salt water, ready to use again and again. I've found that I just need to add more salt to the water now and then to freshen it up, because some of the salt bonds with the copper and comes out in the filtering process. Happy etching everyone!
***EDIT*** Since writing this post I have discovered that while you can re-use your solution for a long long time, it will eventually wear out. Once you start noticing your etching isn't as crisp as before, it's taking a lot longer or you're getting funky textures, replace the solution. Adding more salt will help extend the life but it will eventually be saturated with copper and won't take any more salt. What can I say, I'm learning as I go!

9 comments:

WildGift said...

Hi, I'm really interested in your recipe of salt and water for etching. Do you have this info somewhere on your blog? Thanks, Lisa

Copperheart said...

Hi Lisa,
you can find more information about the process in this tutorial http://copperheartdesigns.blogspot.com/2010/01/electrolytic-copper-etching.html
I don't really have a "recipe" I just add salt to water until I have a saturated solution.

staceypostus said...

Oh, this is so simple and brilliant. Thanks for the tip! :D

Strigeda said...

Hi there, thanks so much for the tip. Can you advise what you do with the solid residue though, is that ok to just put in the household bin? Thank you!

Copperheart said...

Yes, I put the dry residue in the household garbage. I believe (and anyone feel free to correct me if I'm wrong) That copper going directly into the water supply is the problem we need to worry about. If you are uncertain just contact your local waste management people and they will tell you how to dispose of it.

Dennis said...

I have been trying this with a few different resists - stop out varnish, ZAcryl hard ground, asphaltum - but they all come off the work within 20 mins to an hour. How do you get your resist to stick?

Copperheart said...

Hi Dennis,
I scrub my metal with a dry scotch-brite pad which cleans the metal and roughs up the surface. The rougher surface seems to help.

Anna said...

The piece came out really nice but I am having a hard time cleaning it. I have used acetone and copper polish but there is still black around the edges of the etching.

Copperheart said...

Hi Anna,
not sure what resist you are using but when I use a paint pen I actually just scrub the resist of the metal with a scotch-brite pad and soapy water. I find that using a solvent sometimes leaves a sticky residue that is hard to get rid of. If you used a different resist you might need to actually soak it in the solvent for a while to get rid of the residue. I remember in college we used wood shavings (like pet bedding) wetted with solvent to scrub away resist. Otherwise, if you have access to a torch and pickle pot, you can get rid of the last bit of residue by heating the metal (with ventilation!) to burn off the residue and then pickling it. Hope that helps.