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First pcb etched with CuCl

First pcb etched with CuCl

2003-05-05 by grantfair2001

Even though my tank of etchant is far from the deep green color which
shows it is at an optimum, I decided to etch a small board tonight. I
hung it in the etchant above the aerator. (I drilled  a hole in one
end and hung it from an insulated wire).

In about 25 minutes one half (the part closest to the etchant surface)
was etched clear. It took another 25 minutes to get the other half
clear. I finally had to hang it upside down to get it cleared. A
horizontal pcb holder is in the planning stages.

In the first 20 minutes or so, I noticed part of the copper on the PCB
was light grey in color. I suspect this was CuCl(I) because when I put
a small amount of green etchant from the tank lid on this area, it
disappeared. This also suggests that there is lots of CuCl(I) still in
solution.

I measured the pH again with indicator paper. The paper showed red (2)
after I emptied the second 4 litre jug of HCl into it a few days ago.
However, today it was 3 (or higher, if the the pH is higher yet and
the etchant is discoloring the indicator paper).

Although there is green etchant on the inner surface of the tank top,
a drop of tank etchant dropped on the same lid is dark brown. So a lot
of CuCl(I) needs to be converted. I am waiting for some fine bubble
diffuser hose. Unfortunately most fish farming is done on the east and
west coasts of Canada, and I am more or less in the middle between the
two.

So things are progressing, if slowly, I am learning about the CuCl
approach, and I have etched my first board. In spite of the long dunk
it looks just fine with all traces intact. Because I haven't had a
totally clear recipe to operate from, things have gone slowly. But I
hope my experience will make it easier for anyone who wants to use
this appraoch in the future.

Grant

Re: [Homebrew_PCBs] First pcb etched with CuCl

2003-05-05 by adam Seychell

Thanks for the update. What you describe about the gray film
on the copper surface during etching is very important
discovery. The film is copper(I) chloride that hasn't had
time to dissolve. I have found the film plays a big part in
slowing down etch rate, so I am not at all surprised it took
   nearly 1 hour to etch your test PCB. Copper(I) chloride is
light gray insoluble solid, but can dissolve in solution
containing chloride ions due to a phenomenon called ion
complexing and this form of the compound look brownish
black. The formation of a copper(I) chloride film is saying
to you that the etchant needs a lot more regeneration.

An interesting trick is to take the copper with the gray
copper(I) chloride film and expose it to light and air while
wet. It dries to a brown powdery coating. Areas that are
kept dark go to gray powder.

The green droplets on the container walls would of been
there long enough time for atmospheric oxygen to oxidize the
copper(I) to copper(II) chloride. The brown droplets have
not yet had this happen.

All the signs show that things are working as expected. For
now, I would suggest passing in the current sparging setup
and wait for the air diffuser hose to arrive. Get it working
in water first, because you want to avoid pulling it in and
out of the etchant and making a mess.

Adam


grantfair2001 wrote:
Show quoted textHide quoted text
> Even though my tank of etchant is far from the deep green color which
> shows it is at an optimum, I decided to etch a small board tonight. I
> hung it in the etchant above the aerator. (I drilled  a hole in one
> end and hung it from an insulated wire).
> 
> In about 25 minutes one half (the part closest to the etchant surface)
> was etched clear. It took another 25 minutes to get the other half
> clear. I finally had to hang it upside down to get it cleared. A
> horizontal pcb holder is in the planning stages.
> 
> In the first 20 minutes or so, I noticed part of the copper on the PCB
> was light grey in color. I suspect this was CuCl(I) because when I put
> a small amount of green etchant from the tank lid on this area, it
> disappeared. This also suggests that there is lots of CuCl(I) still in
> solution.
> 
> I measured the pH again with indicator paper. The paper showed red (2)
> after I emptied the second 4 litre jug of HCl into it a few days ago.
> However, today it was 3 (or higher, if the the pH is higher yet and
> the etchant is discoloring the indicator paper).
> 
> Although there is green etchant on the inner surface of the tank top,
> a drop of tank etchant dropped on the same lid is dark brown. So a lot
> of CuCl(I) needs to be converted. I am waiting for some fine bubble
> diffuser hose. Unfortunately most fish farming is done on the east and
> west coasts of Canada, and I am more or less in the middle between the
> two.
> 
> So things are progressing, if slowly, I am learning about the CuCl
> approach, and I have etched my first board. In spite of the long dunk
> it looks just fine with all traces intact. Because I haven't had a
> totally clear recipe to operate from, things have gone slowly. But I
> hope my experience will make it easier for anyone who wants to use
> this appraoch in the future.
> 
> Grant
> 
> 
> 
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
> 
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> Homebrew_PCBs-unsubscribe@yahoogroups.com
> 
>  
> 
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/ 
> 
>

Re: [Homebrew_PCBs] First pcb etched with CuCl

2003-05-06 by Francisco Peña

I have experienced uneven etching using CuCl too. I etch my boards horizontally facing up, and the etching happens from the edge to the center of the board, and takes about 30minutes to have an 8x6" board done. The end result is perfect and the traces look fine, although I'm a bit concerned about the time too. I think my mix needs more oxigen too.

Fp
www.tonepad.com
Show quoted textHide quoted text
  ----- Original Message ----- 
  From: grantfair2001 
  To: Homebrew_PCBs@yahoogroups.com 
  Sent: Sunday, May 04, 2003 9:59 PM
  Subject: [Homebrew_PCBs] First pcb etched with CuCl


  Even though my tank of etchant is far from the deep green color which
  shows it is at an optimum, I decided to etch a small board tonight. I
  hung it in the etchant above the aerator. (I drilled  a hole in one
  end and hung it from an insulated wire).

  In about 25 minutes one half (the part closest to the etchant surface)
  was etched clear. It took another 25 minutes to get the other half
  clear. I finally had to hang it upside down to get it cleared. A
  horizontal pcb holder is in the planning stages.

  In the first 20 minutes or so, I noticed part of the copper on the PCB
  was light grey in color. I suspect this was CuCl(I) because when I put
  a small amount of green etchant from the tank lid on this area, it
  disappeared. This also suggests that there is lots of CuCl(I) still in
  solution.

  I measured the pH again with indicator paper. The paper showed red (2)
  after I emptied the second 4 litre jug of HCl into it a few days ago.
  However, today it was 3 (or higher, if the the pH is higher yet and
  the etchant is discoloring the indicator paper).

  Although there is green etchant on the inner surface of the tank top,
  a drop of tank etchant dropped on the same lid is dark brown. So a lot
  of CuCl(I) needs to be converted. I am waiting for some fine bubble
  diffuser hose. Unfortunately most fish farming is done on the east and
  west coasts of Canada, and I am more or less in the middle between the
  two.

  So things are progressing, if slowly, I am learning about the CuCl
  approach, and I have etched my first board. In spite of the long dunk
  it looks just fine with all traces intact. Because I haven't had a
  totally clear recipe to operate from, things have gone slowly. But I
  hope my experience will make it easier for anyone who wants to use
  this appraoch in the future.

  Grant


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

Re: [Homebrew_PCBs] First pcb etched with CuCl

2003-05-07 by Mike Putnam

Even the Ferric Chloride etchant will etch unevenly and take some time in
cold etchant. Is CuCl the same? I have always heated the Ferric but am
wondering if this is the thing to do with the CuCl.
-Mike

----- Original Message -----
From: "Francisco Pe\ufffda" <mute@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, May 06, 2003 10:00 AM
Subject: Re: [Homebrew_PCBs] First pcb etched with CuCl


> I have experienced uneven etching using CuCl too. I etch my boards
horizontally facing up, and the etching happens from the edge to the center
of the board, and takes about 30minutes to have an 8x6" board done. The end
result is perfect and the traces look fine, although I'm a bit concerned
about the time too. I think my mix needs more oxigen too.
Show quoted textHide quoted text
>
> Fp
> www.tonepad.com
>
>
>
>
>   ----- Original Message -----
>   From: grantfair2001
>   To: Homebrew_PCBs@yahoogroups.com
>   Sent: Sunday, May 04, 2003 9:59 PM
>   Subject: [Homebrew_PCBs] First pcb etched with CuCl
>
>
>   Even though my tank of etchant is far from the deep green color which
>   shows it is at an optimum, I decided to etch a small board tonight. I
>   hung it in the etchant above the aerator. (I drilled  a hole in one
>   end and hung it from an insulated wire).
>
>   In about 25 minutes one half (the part closest to the etchant surface)
>   was etched clear. It took another 25 minutes to get the other half
>   clear. I finally had to hang it upside down to get it cleared. A
>   horizontal pcb holder is in the planning stages.
>
>   In the first 20 minutes or so, I noticed part of the copper on the PCB
>   was light grey in color. I suspect this was CuCl(I) because when I put
>   a small amount of green etchant from the tank lid on this area, it
>   disappeared. This also suggests that there is lots of CuCl(I) still in
>   solution.
>
>   I measured the pH again with indicator paper. The paper showed red (2)
>   after I emptied the second 4 litre jug of HCl into it a few days ago.
>   However, today it was 3 (or higher, if the the pH is higher yet and
>   the etchant is discoloring the indicator paper).
>
>   Although there is green etchant on the inner surface of the tank top,
>   a drop of tank etchant dropped on the same lid is dark brown. So a lot
>   of CuCl(I) needs to be converted. I am waiting for some fine bubble
>   diffuser hose. Unfortunately most fish farming is done on the east and
>   west coasts of Canada, and I am more or less in the middle between the
>   two.
>
>   So things are progressing, if slowly, I am learning about the CuCl
>   approach, and I have etched my first board. In spite of the long dunk
>   it looks just fine with all traces intact. Because I haven't had a
>   totally clear recipe to operate from, things have gone slowly. But I
>   hope my experience will make it easier for anyone who wants to use
>   this appraoch in the future.
>
>   Grant
>
>
>         Yahoo! Groups Sponsor
>
>
>
>
>
>   Be sure to visit the group home and check for new Bookmarks and files:
>   http://groups.yahoo.com/group/Homebrew_PCBs
>
>   To unsubscribe from this group, send an email to:
>   Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
>   Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> Be sure to visit the group home and check for new Bookmarks and files:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> To unsubscribe from this group, send an email to:
> Homebrew_PCBs-unsubscribe@yahoogroups.com
>
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>

Re: First pcb etched with CuCl

2003-05-07 by grantfair2001

One of the variables affecting etch time in CuCl is etchant
temperature. However, you have to be careful not to melt or soften
your etchant tank. And, the amount of HCl in the tank is another
variable - I'm not sure how it is related to etch time. 

But, if you heat a high enough concentration of HCl, it will "fume".
These are a health hazard if breathed in, or if they get in your eyes. 
And the fumes will corrode metal it comes in contact with; steel for
sure as I learned the hard way.

I don't know the concentration of HCl which I got fuming. However, it
was 20 Baume (31.5%) before I diluted it; I started with one part HCl
to 2 parts water. Later I added more HCl. I had not heated it very
much- I was running air from a large vacuum pump exhaust into the
sparger. The pump got very warm to the touch, and so did the air. I
think the heat was what provoked the fuming. I use a less powerful
pump now and have not had a return of the fuming problem.

Anyway, you would either have to have a pretty close control over your
process (amount of acid, ?amount of copper, ?amount of air,
temperature of etchant) to be sure fuming would not be a problem, or
at least supervise the process closely. The other option is to provide
ventilation to get rid of the fumes. One list member suggested a
simple vent such as an ABS pipe going from your etchant tank to the
outside of your house would do the trick. So far I don't think that
will be necessary.

But my basement is about 60 deg. F at present. That may change in the
summer so I will have to keep an eye out for fumes.

As far as an even etch rate - I don't know what all goes into getting
it even. Anyone know? My first board etched fastest at the top (it was
vertical); it was in the bubblestream. I don't know how the bubbles
were placed since I just put the small bubble sparger in the bottom
under the etchant. Maybe a uniform exposure to bubbles is an element
in getting it even. I want to try my large sparger (the Think and
Tinker version) with another PCB because it provides a great deal of
etchant movement. It's bubbles are fairly large, by design, to agitate
the etchant.

Grant

--- In Homebrew_PCBs@yahoogroups.com, "Mike Putnam" <circuit@g...> wrote:
> Even the Ferric Chloride etchant will etch unevenly and take some
time in
> cold etchant. Is CuCl the same? I have always heated the Ferric but am
> wondering if this is the thing to do with the CuCl.
> -Mike
> 
> ----- Original Message -----
> From: "Francisco Peña" <mute@i...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Tuesday, May 06, 2003 10:00 AM
> Subject: Re: [Homebrew_PCBs] First pcb etched with CuCl
> 
> 
> > I have experienced uneven etching using CuCl too. I etch my boards
> horizontally facing up, and the etching happens from the edge to the
center
> of the board, and takes about 30minutes to have an 8x6" board done.
The end
Show quoted textHide quoted text
> result is perfect and the traces look fine, although I'm a bit concerned
> about the time too. I think my mix needs more oxigen too.
> >
> > Fp
> > www.tonepad.com