Homebrew PCBs

Just in case any are interested, I Electro-etch most boards.
(Reverse Electroplating)
Than just a bit of Ferric Chloride to finish them off at the end as 
it is impossible to Electro-etch the last little bit.
This Reduces my cost to almost Nothing.

See the "Electro Etching" article on my Webste at: 
http://www3.telus.net/chemelec/Projects/Projects.htm

I use Shipleys Photo Resist. They have recently Improved it and it 
works fantastic.

One other piece of advice, Print Two Positives and tape them one over 
the other. It gives a Much Better Contrast for blocking the 
Ultraviolet.

Take care.........Gary

I'd like to hear some of the details about your electro etching process.

We considered this many years ago, but could never get it to work to the degree required.  Using a secondary etch process in a production process at the time was not economically feasible as you would have to construct a completely new production line costing many $$$ as compared to the conveyorized spray systems then in use.

[Non-text portions of this message have been removed]

sounds good, or have I missed something here ...
what about the unconnected copper area's of the board ? 
I am thinking that the unconnected copper would need a Jumper wire as such to complete the circuit so as to be etched

 :-) Thomas

  ----- Original Message ----- 
  From: Earl T. Hackett, Jr. 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Friday, November 05, 2004 9:42 AM
  Subject: Re: [Homebrew_PCBs] Electro-Etching


  I'd like to hear some of the details about your electro etching process.

  We considered this many years ago, but could never get it to work to the degree required.  Using a secondary etch process in a production process at the time was not economically feasible as you would have to construct a completely new production line costing many $$$ as compared to the conveyorized spray systems then in use.

  [Non-text portions of this message have been removed]



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[Non-text portions of this message have been removed]

--- In Homebrew_PCBs@yahoogroups.com, "Thomas" <teecee@c...> wrote:
> sounds good, or have I missed something here ...
> what about the unconnected copper area's of the board ? 
> I am thinking that the unconnected copper would need a Jumper wire
as such to complete the circuit so as to be etched
> 

They are connected until (almost) all the exposed copper is removed. 
I would guess that some of the inside areas would not etch completely.
 He mentions a final etch with traditional etchants.  Clearly, a
little FeCl, CuCl or AP would go a very long way.

The need to have 2 etching set ups outweighs the benefits for me but
it is kind of cool.

Phil

--- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Thomas" <teecee@c...> wrote:
> > sounds good, or have I missed something here ...
> > what about the unconnected copper area's of the board ? 
> > I am thinking that the unconnected copper would need a Jumper wire
> as such to complete the circuit so as to be etched
> > 
> 
> They are connected until (almost) all the exposed copper is 
removed. 
> I would guess that some of the inside areas would not etch 
completely.
>  He mentions a final etch with traditional etchants.  Clearly, a
> little FeCl, CuCl or AP would go a very long way.
> 
> The need to have 2 etching set ups outweighs the benefits for me but
> it is kind of cool.
> 
> Phil

Yes, This is Correct.
I realize for Commerical Production this is Probably Not Practical, 
But for Hobbiests, It can save a lot of Dollars and just adds an 
extra step.

Specific Questions will be answered if you email me through my 
website. Sometimes I don't get into Yahoo Groups very often.

Towards the end of the Electro-Etching it is Important to remove it 
Soon, Rather than Later or you will get Undercutting. 
I Recommend a Glass or clear plastic container, with a light behind 
the board, making it is Easy to see the etching progress. When Light 
Appears to show through the board, remove it and finish it in the 
FeCl.

Try it and Have Fun...........Gary

--- In Homebrew_PCBs@yahoogroups.com, "Gary" <chemelec@h...> wrote:
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Phil" <phil1960us@y...> 
wrote:
...
> > The need to have 2 etching set ups outweighs the benefits for me 
but
> > it is kind of cool.
> > 
...
> Yes, This is Correct.
> I realize for Commerical Production this is Probably Not Practical, 
> But for Hobbiests, It can save a lot of Dollars and just adds an 
> extra step.
> 
> Specific Questions will be answered if you email me through my 
> website. Sometimes I don't get into Yahoo Groups very often.

I agree that it does save some money but if one uses CuCl, like I do, 
the cost difference isn't nearly as large since I can regenerate my 
etchant via bubbling or kick-start it with about 50 mL of H2O2.  And 
I only have to have one set of chemicals, one etching tank, and so 
on. Still, I think its a pretty cool idea and definitely worth 
considering if one is using consumable etchants (like FeCl or AP).  
It is definitely worth it if it significantly reduces the disposal 
problem.

It would be good to answer questions here - they are likely to be of 
interest to many of our members.

Phil

two things,

first, the component legend is easily freed from paper residue by abrasive  
pad (meant for cleaning copper tubing to solder), which i use for cleaning  
the copper too. then use a paper towel (use shop-grade recycled material  
which is pretty abrasive) and polish it to a shine with a few rubs.
(could use polishing wheel too.)
Gives a perfect shiny component legend, similar looking to black  
silkscreen (actually much better ;-) )
(Note: previously i used abrasive kitchen cleaner and a lot more effort to  
polish it and remove the residue).

Also keep in mind component legend can NOT be re-done. Once it's on it's  
on. You can't remove it fully.


second, alignment of double sided boards or copper artwork bottom /  
component legend top in one go:
I realised the problem with aligning double-sided things was that the  
paper shifted when fed into the
fuser no matter how hard i tried to glue/tape it etc.
I needed a glue to stick the paper directly to the PCB. The obvious is to  
use toner!
i just make a 5mm broad strip of solid toner above the artwork, and stick  
it on with a clothes iron.
Works great. only iron the strip to prevent any bad effects on the other  
artwork. Maybe the artwork
itself could be used to stick it with the iron, and the laminator only to  
ensure a uniform adhesion.
The 5mm strip is not a problem for me because i use it to clamp the board  
during etch.

not yet had time to work on the "paper shrinkage caused by heating in the  
fuser" issue.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
> 
> two things,
> 
> first, the component legend is easily freed from paper residue by
abrasive  
> pad (meant for cleaning copper tubing to solder), which i use for
cleaning  
> the copper too. then use a paper towel (use shop-grade recycled
material  
> which is pretty abrasive) and polish it to a shine with a few rubs.
> (could use polishing wheel too.)
> Gives a perfect shiny component legend, similar looking to black  
> silkscreen (actually much better ;-) )
> (Note: previously i used abrasive kitchen cleaner and a lot more
effort to  
> polish it and remove the residue).

I do a hot peel - just pull the paper off when its still hot.  Works
quite well and its a lot faster.  It doesn't leave quite as much toner
but its very legible and no cleaning is needed.


> 
> second, alignment of double sided boards or copper artwork bottom /  
> component legend top in one go:
> I realised the problem with aligning double-sided things was that the  
> paper shifted when fed into the
> fuser no matter how hard i tried to glue/tape it etc.
> I needed a glue to stick the paper directly to the PCB. The obvious
is to  
> use toner!
> i just make a 5mm broad strip of solid toner above the artwork, and
stick  
> it on with a clothes iron.
> Works great. only iron the strip to prevent any bad effects on the
other  
> artwork. Maybe the artwork
> itself could be used to stick it with the iron, and the laminator
only to  
> ensure a uniform adhesion.
> The 5mm strip is not a problem for me because i use it to clamp the
board  
> during etch.

I've not had any problem with tacking the artwork (vs a special toner
strip) before feeding through the laminator.   But, I don't bother
with that anymore - I use a carrier for the board/paper assembly.  I
fold a sheet of children's "construction paper", put the assembly
inside and and feed it through the laminator.  I've had good to great
alignment on about 30 boards I've done (yeah, i really should have
sent them out...).  Its my guess that the paper to paper contact slips
more easily than paper to copper does.  Prior to using a carrier or
tacking I was getting 5-10 mils of mis-registration.  Now I think I'm
getting around 2-3 mils or less which is better than the accuracy of
my drilling.