Hi everyone, again,
sorry to bother this group again -- it's just the most suitable I've found for my questions. :-)
Anyway, I'm a tad curious about the two different chemicals I use to make PCBs - I never did much chem in high school, so I'm a bit weak in that area.
1) I'm not sure what exact chemical I use to develop my boards, but it's part of the Kinsten range of products for hobbyist PCB manufacture, and it's called "Developer DP-50". Anyway, it says that it only has an 8-hour life once combined with water, but I've read mixed reports on the 'net as to if you can use it after that or not. Any ideas? I'm just trying to save a bit of cash, because I don't want to have to use up a new sachet of developer every time I make a PCB (even though I've probably only used 5% of its potential).2) I use Ammonium Persulphate to etch my boards, using (once again) a Kinsten etching tank. Now, because this stuff is a lot more potent, I've read that you're not supposed to store it at all, and discard after use. Here, again, it's the same question -- can I store it and re-use it? otherwise, I'm throwing out a lot of good etchant. I've poured one lot that I used in a clear plastic bottle, and it's kept for about a week - it was slightly blue when it came out of the tank, but I think that's 'cos of the copper, right? Anyway, it seems to be the same
- any reason I can't reuse this?
3) again with the Ammonium Persulphate, when would I know to discard the solution? I've read that it's when it goes blue, but how blue is blue? :-) Are there any other indicators I can use (besides it not etching anymore? :-P )Oh, and if it's any help, here's the products I'm using, to give you an idea:
Cheers, thanks in advance for any help, and sorry if they're just stupid chem questions that most people would know as basic knowledge. :-)
Michael