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, 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 ?
--
Dick
GM0MNL

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, 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 ?

It's just as easy to dispose of as FeCl3. The solution doesn't keep very
well, unlike FeCl3.

Leon
--
Leon Heller, G1HSM
Email:
My low-cost Philips LPC210x ARM development system:
http://www.geocities.com/leon_heller/lpc2104.html

looking for the info you recieved about diy photo etching..ie exposure times
etc.. exposure boxes etc...
i dont suppose you kept the info ???

simon

"Dick" wrote in message
...
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, 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 ?
--
Dick
GM0MNL

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, 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 ?

Last year, as an experiment, I marked up a small piece of double-sided
copperclad with Sharpie and similar marking pens. I then etched it in
a solution of sodium monopersulphate (cheaply available at pool-supply
stores - it's used as an oxygen shock) and hot tap water. A plastic
cup served as the container, and I agitated gently by hand.

It definitely etched! As I recall, 10-15 minutes was sufficient to
etch the unprotected areas down to bare fiberglass. The etch was easy
to monitor as the solution is clear to start with, and turns a clear
blue-green as the copper is etched. The different marking pens I'd
tried had different amounts of resistance to the etch... one or two
stood up fairly well, the others did not.

I haven't tried actually making a functional board with this etchant
yet, but may do so in the near future - I've refurbed an old HP
flatbed plotter, and converted the pen-holder to use Staedtler (sp?)
red-ink permanent marker pens which have a good reputation for etchant
resistance. Some form of improved solution-heating and
agitation/bubbling arrangment would probably be a good idea, to get a
quick and consistent etch.

Disposal can be quite easy. Mix up a solution of sodium carbonate
(washing soda, also sold at pool-supply stores as a mild alkali to
raise the pH of pool water) and titrate it into the used solution. The
dissolved copper will convert to copper carbonate, and precipitate
out... copper carbonate isn't very soluble in water. Strain the
solution through a paper filter (e.g. coffee filter) to separate the
carbonate from the remaining solution (which should be clear once
again if you added enough sodium carbonate).

I just dumped the copper-free solution into my swimming pool, and
discarded the filter in the trash. If you want to really immobalize
the copper carbonate, you could mix it into a batch of
plaster-of-paris or portland cement and let it harden up, and then
trash the resulting piece of rock.

--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!

or dick tell me how you made your light boxe..and some idea on exposure
times..are you using pre sensitised pcb or are you spraying your own??if so
what make of gunk you using..tnx..simon..
oh i found the previous posts...
"Dick" wrote in message
...
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, 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 ?
--
Dick
GM0MNL

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

Ferric chloride solution is somewhat acidic. If you add some baking
soda, you will precipitate out almost all the iron. If you first use
the solution till it doesn't etch well any longer, there's not a whole
lot of ferric left in it; it's mostly ferrous, which isn't
particularly corrosive. You can toss in a couple old steel nails to
finish the conversion from ferric if you wish. Considering the amount
of rust in junkyards, I wouldn't be concerned about the small amount
of ferrous you're adding. HOWEVER, I would be more concerned with the
copper ions, which, I believe, are considerably more toxic than iron
to most life on earth, including things that digest sewage. If it's
tiny hobby amounts, it may not be a significant increment, because of
all the copper plumbing in homes, but to be safe you can lock it up in
Portland cement as Ian says.

Another etchant to consider is cupric chloride. You can make a
self-regenerating etchant; etching boards makes more etchant.
Instructions at http://users.rcn.com/rexa/Projects/CuCl_ech.html.

Cheers,
Tom


Dick wrote in message ...
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, 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 ?

In article , wrote:


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, 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 ?

It's just as easy to dispose of as FeCl3. The solution doesn't keep very
well, unlike FeCl3.

Leon
Use CuCl2 + HCl. After etching the Cu 2+ (cupric) ion goes to Cu 1+
(cuprous). Bubbling air thru it oxidizes the cuprous back to cupric [you'll
know when its done because the cupric is a bright emerald green]. Disposal is
easy -- you don't dispose of it, just reuse.
Do a Google search for CuCl2 and PWB etching and you can find more details.

Dr. G.