[ELECTRON] Advice on Ferric Chloride pellets for PCB etching

[Andrew Back]

On (15:23 05/08/11), Roy Mohan Shearer wrote:
> Hi folks,
> 
> I am planning on trying out ferric chloride crystals (as opposed to
> the pre-made ferric chloride solution) for some PCB etching I'm doing
> next week (don't do it very often). Any advice here I should know?

I spoke with a few people about this recently and it seems that many 
have moved on to using a clear etchant, the name of which I forget but
googling just now suggests ammonium peroxydisulfate. Which makes sense, as I
had a tour of a commercial PCB plant a few months ago and they said they
used an ammonia based etchant. 

One of the DIY PCB folks I spoke with is presenting at the next Open Source
Hardware User Group meeting (London, I'm afraid). He uses a process which is
reliable enough that school kids are using it to etch boards to take 0.5mm
pitch 64pin surface mount packages. Might be worth dropping him a line:

http://oshug.org/event/12#DIYDSPCB

ISTR that he said there is no way this could be done with ferric chloride.

Of course, if you're in London around then you should definitely come along.
In related news we're organising a whole day of workshops late October which
might be worth making the trip down for. There will be four parallel tracks:
designing for and practical 3D printing, building Android accessories with
the Google ADK, building the Internet of Things with Open Source Hardware,
and creating and managing open source hardware projects. The placeholder
page for this (to be updated soon-ish): 

http://oshug.org/event/oshcamp

Cheers,

Andrew

-- 
Andrew Back
a at smokebelch.org