ferric chloride alchemy?

[tardishead]

if you make a lot of PCBs you will find it is not cheap. especially Ferric chloride. I get Riston PCBs cut to any size I want and at wholesale prices direct from the supplier. last time I went there I said have you got any Ferric Chloride - he thought I was mad - he said he only ever bought one batch of FC 40 years ago and he uses a simple trick that keeps it going indefinitely. he wouldnt tell me his secret. are there any chemists out there?????

 

[CJ]

don't mess with that primitive stuff.
get yourself some MG Chemicals Ammonium Persulfate or some Mega fine etch crystals (sodiumpersulfate).

 

[NewYorkDave]

Um, he pisses in it?

:?

 

[owel]

[quote author="cjenrick"]don't mess with that primitive stuff.
get yourself some MG Chemicals Ammonium Persulfate or some Mega fine etch crystals (sodiumpersulfate).[/quote]

I'm still using FeCl powder... what are the advantage of MG chemicals?

And where can you buy them?

 

[mcs]

All I know is that you have to add :guinness: if you use a foam etch machine...

Best regards,

Mikkel C. Simonsen

 

[CJ]

http://www.web-tronics.com/ US.

I don't know for Europe.

 

[tommytones]

After a while, the copper settles to the bottom. It's filter time!! No real magic. I've been going with a batch I've had for over 2 years now.

 

[owel]

What filter do you use? Coffee filters?

 

[fum]

[quote author="tommytones"]After a while, the copper settles to the bottom. It's filter time!! No real magic. I've been going with a batch I've had for over 2 years now.[/quote]

Really? Hmmm, mine stopped etching stuff after a couple months ( that was after maybe 10-15 boards). Are you talking ferric chloride or sodium persulphate Tommy ( I'm confused) :?



ju

 

[Aharon]

I asked the same question at Aron's forum and got this answer:

http://diystompboxes.com/sboxindex.php?topic=25425&highlight=filtering+ferric+chloride

TAke care
Aharon

 

[crazydoc]

[quote author="tardishead"]if you make a lot of PCBs you will find it is not cheap. especially Ferric chloride. [/quote]
I get it for $8 a liter - that's pretty cheap.
I think the reaction is oxidation/reduction, where metallic copper gives up electrons to the ferric ion, and copper is ionized to the cupric state which is soluble in water. But when you're out of ferric iron, you're not going to etch anymore board, no matter what you filter out.

Maybe his trick is to replenish the solution with HCl (hydrochloric acid) which I believe will also etch copper boards, though is considerably more toxic to human skin and respiratory tract. Or maybe the HCl can oxidize the iron back to the ferric state?

This is just from faint memories of Chem 101 many years ago, so take it with a grain of salt.

 

[CJ]

I wish Jake would post some pics of him etching boards in an out of control HCL solution!
Enviromental Protection Agency in Denmark? I don't think so!