My new favorite etchant

From the MAKE Flickr pool

I love etching my own PCBs. It’s a great way to incorporate some of art-school skills with my love for DIY electronics. Up until now, I’d always used traditional ferric chloride to etch my boards, though I’d heard many sing the praises of an alternative etchant easily made from common ingredients. Tired of mail-ordering ferric and dealing with proper disposal, I decided to give cupric chloride a try.

Following Open Circuits’ recipe, I picked up some muriatic acid from the local hardware store and a bottle of hydrogen peroxide 3% from the pharmacy. After setting up next to my big window fan, I slowly added 16oz of the muriatic to an equal amount hydrogen peroxide, resulting in a clear solution. Shortly after immersing my masked PCB and agitating a bit, the etchant turned a brilliant green hue as it began work on the exposed copper. Several minutes of gentle sloshing left me with a perfectly etched board – plus a etchant that can will last me a very long time. For me, that’s the real ‘selling point’ of cupric chloride – by oxygenating (air-bubbling) or adding some more H2O2 to the solution, I’ll be able to refresh this batch once it’s spent – awesome. I’m left wondering why I hadn’t tried this sooner!