I etched my first board with the vinegar/h2o2 recipe and had success. I'll continue to use this method as well as trying the muriatic acid method.

The instructions that I've seen online don't talk much about reusing the etchant. The most detail I've seen is "recharge the etchant later with more h2o2".

Firstly, does anybody know if/how you can/should reuse the etchant?

Secondly, if you do add more h2o2:

• how much?
• doesn't this just dilute the mixture (especially after several additions)?
• do you drain-off an equal volume first (otherwise you'll end up overfilling your tank)

Thanks

 

I don't. There is a chemical reaction going on between the muriatic acid and the H2O2, it doesn't stop. The chemicals are extremely cheap, and you don't need much. If you are using a lot then maybe rethink how you are doing it. I use disposable tupperware, and make a 2 part line and a 1 part line on it's side.

I find a weed I don't like to dispose of the used etchant.

Ferric Chloride is a different story, the used chemical becomes a solid for the most part. It is stable (unlike the others), and you can store it indefinitely.

 

Thanks. You sold me on the weed killer.

 

Yea, muriatic acid and H2O2 are cheap, just mix a fresh batch each time as the H2O2 breaks down rather quickly.