I'm trying my hand at making my own PCBs. Using the positive photo development method and ammonium persulphate for etching.
Does anyone know how long the etchent can be kept once mixed before it becomes useless? Also, what are the optimum temps for both the developer and ammonium persulphate to function at their best?
Videos online show the etching happening quite quickly and my boards are taking a long time. Wondering if temp is to blame. Doing it in the garage so the etch bath is slightly warmer than body temp[40-50C]. Photo development is cooler than body temp like about 25C.