Dick wrote:
Thanks to the group for all the past advice given on PCB
drafting software & UV exposure boxes, it's all being put to good use.

In the past I've used ferric chloride professionally as my
etchant (and left disposal of the etching solution to the work's
chemist) but now I'm doing things for myself safe disposal is going to
be my problem,

Safe disposal of amateur quantities of ferric chloride is easy enough -
just solidify it in a small bag of cement.

searching on the web for an answer ammonium and sodium
persulphate come up as a suitable alternatives but not ones I've used.
Does anyone have experience of using persulphates as a D-I-Y PCB etchant
?
Are they as good as ferric chloride, are there any problems with using
them & how easy is it to dispose of the spent solution ?

I haven't, but a friend has used ammonium persulphate and speaks very
well of it. He says it etches at least as well as ferric chloride, and
after use the remaining ammonium persulphate can be recrystallised out
of the copper sulphate solution.

But unfortunately he's in no position to demonstrate this any more,
because we haven't been able to find a source of small quantities (up to
a few kilos) in the UK. Apart from ferric chloride, and sodium
persulphate (which isn't as effective as the ammonium salt) it seems
impossible to buy small quantities of general chemicals, these days...
unless someone knows better... and I hope someone does...


--
73 from Ian G3SEK 'In Practice' columnist for RadCom (RSGB)
Editor, 'The VHF/UHF DX Book'
http://www.ifwtech.co.uk/g3sek