Tools, I use a car battery hygrometer for measuring density. The car battery hygrometers do not cover the full range of acceptable densities for etching but does cover the optimum.
For acid measurements I do periodically titrate using the method given by Adam in his page. Most of the time I just add a dash of acid at the start of each session. (A pinch of salt, two cloves of garlic and splash of white wine) I bubble during etching and for a while afterwards to regenerate the mixture. Also my tank is about 5 times bigger than I would use if I was using FeCl. If you have a lot of spare etching capacity you wont ever run into copper saturation. The etchant does grow but very very slowly. In fact it does not grow fast enough for me to give it away. Most people I know want to start using it when they see it so I have to throw extra scrap copper in and bubble for days to get extra etchant to give away. (I am always titrate after eating a lot of copper to grow the bath) The air DOES regenerate it completly. You don't need to add H2O2. But I do keep some H2O2 spare in case I need to do a lot of etching at once. The H2O2 gives you an instant regeneration rather than having to wait hours. The etch rate I get is a little slower than FeCl3. However it does not give as good an edge as the FeCl. It gives as good a detail as H2O2/HCl or amonia persulphate. In my experience none of them compete with FeCl3 for resolution. If you run CuCl (or H2O2/HCl) at elevated temp then the speed can be better than FeCl3 but at the expense of more undercutting. I only run my etchant at 30 degrees C. At 40 degrees C (105F) I get a bit much fuming for my likeing (I probably keep it too green and too high in acid most the time) _______________________________________________ geda-user mailing list [email protected] http://www.seul.org/cgi-bin/mailman/listinfo/geda-user
