This is 17.5% strength HCl, and 9% H2O2. Assuming this is strong enough to start a cupric chloride bath (with a sufficient amount of air and scrap copper provided), what sort of mix ratio would I need to make a viable etchant?
Do I need to target a specific pH? That is, do I need to buy litmus paper and so on too?
What about titration and specific gravity control -- is that necessary? I have some sodium hydroxide granules in the cupboard (CIF Photoresist Developer; I've been using MEGA CPD5 instead because it's less harmful and harder to screw up), but would need to hunt down a suitable indicator chemical and glassware...