PCB etchants, was 3B2 floppies

On 02/15/2013 12:26 AM, Dave McGuire wrote: Then you're one up on me. I've used it in electroplating (pretty blue crystals) and in etching zinc and tin, but not for etching PCBs. You can use it as a source of copper ions to prepare a solution (usually using HCl) with the [CuCl4]2? complex, which is an excellent PCB etchant. But many copper salts--even elemental copper--can do that. But I can put a PCB in a solution of CuSO4 and nothing remarkable will happen. Here's a nice video showing the chemistry of 10 PCB etchants. Some are really nasty and you'd have to be out of your mind to use them. But note that CuSO4 only occurs as a source of copper ions in the presence of an acid or as a reaction product, not the etchant: http://www.youtube.com/watch?v=Q4tWEse2rDI --Chuck