Homebrew PCBs

Howdy

I have this "hare-brained" idea on another method to regenerate Cuperic Chloride etchant.  I plan on getting some "Oxygen Tablets" (used in fish tanks, live bait tanks, etc), and placing one of the tablets in a closed container of water to generate oxygen.  
The container will be connected via a tube to my bubbler, rather than my air pump. As a result, pure oxygen will be bubbled, rather than air.  I'm guessing that it should be as fast a regenerator as Hydrogen Peroxide . . . and not any more expensive when compared to 30 or 40 volume Hydrogen Peroxide - plus the etchant will not be diluted.
Any comments ? Has anyone tried this?  I'll post my results

Ken

I wonder if it would be simpler to just buy a small bottle of oxygen
from the local pharmacy or welding supply store.

Ken Stuempges wrote:
> 
> 
> 
> Howdy
> 
> I have this "hare-brained" idea on another method to regenerate Cuperic 
> Chloride etchant. I plan on getting some "Oxygen Tablets" (used in fish 
> tanks, live bait tanks, etc), and placing one of the tablets in a closed 
> container of water to generate oxygen.
> The container will be connected via a tube to my bubbler, rather than my 
> air pump. As a result, pure oxygen will be bubbled, rather than air. I'm 
> guessing that it should be as fast a regenerator as Hydrogen Peroxide . 
> . . and not any more expensive when compared to 30 or 40 volume Hydrogen 
> Peroxide - plus the etchant will not be diluted.
> Any comments ? Has anyone tried this? I'll post my results
> 
> Ken
> 

I don't see why it wouldn't work. A bit expensive though for what you 
might possibly gain in relation to regeneration speed compared to room 
temperature air bubbling.

Are you having trouble with air regeneration ?
Is the acid high enough ?

The solution doesn't have to be bright green in order to etch. Its 
difficult to specify, but etch speed only slows down when its "really 
dark brown". If you take a tank sample in a test tube, dilute ~10:1 with 
water and if you don't see any visible signs of white precipitate then 
the copper(I) chloride is below limits and should etch ok.

Adam

There are ways to increase efficiency using pure oxygen, google for
downstream reactor (also used for fish tanks).

I already tried using a piece of a chlorine tablet (from a pool) but
it did not work. Oxygen should.

ST

On Sun, Jul 5, 2009 at 11:12 PM, Ken Stuempges<ozarkshermit@...> wrote:
> Howdy
>
> I have this "hare-brained" idea on another method to regenerate Cuperic Chloride etchant.  I plan on getting some "Oxygen Tablets" (used in fish tanks, live bait tanks, etc), and placing one of the tablets in a closed container of water to generate oxygen.
> The container will be connected via a tube to my bubbler, rather than my air pump. As a result, pure oxygen will be bubbled, rather than air.  I'm guessing that it should be as fast a regenerator as Hydrogen Peroxide . . . and not any more expensive when compared to 30 or 40 volume Hydrogen Peroxide - plus the etchant will not be diluted.
> Any comments ? Has anyone tried this?  I'll post my results
>
> Ken

Well - I had to try it at least . . .
The Oxygen tabs I tried did not generate enough oxygen to make many bubbles in the tank.  Perhaps the tabs were old, but I doubt if new ones would have been much better.  

Ken


--- In Homebrew_PCBs@yahoogroups.com, "Ken Stuempges" <ozarkshermit@...> wrote:

>
> Howdy
> 
> I have this "hare-brained" idea on another method to regenerate Cuperic Chloride etchant.  I plan on getting some "Oxygen Tablets" (used in fish tanks, live bait tanks, etc), and placing one of the tablets in a closed container of water to generate oxygen.  
> The container will be connected via a tube to my bubbler, rather than my air pump. As a result, pure oxygen will be bubbled, rather than air.  I'm guessing that it should be as fast a regenerator as Hydrogen Peroxide . . . and not any more expensive when compared to 30 or 40 volume Hydrogen Peroxide - plus the etchant will not be diluted.
> Any comments ? Has anyone tried this?  I'll post my results
> 
> Ken
>

Are they supposed to release oxygen in gaseous form?  Maybe they work
differently.

ST

On Fri, Jul 10, 2009 at 7:05 PM, Ken Stuempges<ozarkshermit@hughes.net> wrote:
> Well - I had to try it at least . . .
> The Oxygen tabs I tried did not generate enough oxygen to make many bubbles in the tank.  Perhaps the tabs were old, but I doubt if new ones would have been much better.
>
> Ken
>

I agree that new ones would not work much better.  
I expect this has been covered but why not get a O2 cylinder and regulator ?

--- On Fri, 7/10/09, Ken Stuempges <ozarkshermit@...> wrote:

From: Ken Stuempges <ozarkshermit@...>
Subject: [Homebrew_PCBs] Re: Oxygen tablets for CuCl regeneration
To: Homebrew_PCBs@yahoogroups.com
Date: Friday, July 10, 2009, 5:05 PM











    
            
            


      
      Well - I had to try it at least . . .

The Oxygen tabs I tried did not generate enough oxygen to make many bubbles in the tank.  Perhaps the tabs were old, but I doubt if new ones would have been much better.  



Ken



--- In Homebrew_PCBs@ yahoogroups. com, "Ken Stuempges" <ozarkshermit@ ....> wrote:

>

> Howdy

> 

> I have this "hare-brained" idea on another method to regenerate Cuperic Chloride etchant.  I plan on getting some "Oxygen Tablets" (used in fish tanks, live bait tanks, etc), and placing one of the tablets in a closed container of water to generate oxygen.  

> The container will be connected via a tube to my bubbler, rather than my air pump. As a result, pure oxygen will be bubbled, rather than air.  I'm guessing that it should be as fast a regenerator as Hydrogen Peroxide . . . and not any more expensive when compared to 30 or 40 volume Hydrogen Peroxide - plus the etchant will not be diluted.

> Any comments ? Has anyone tried this?  I'll post my results

> 

> Ken

>




 

      

    
    
	
	 
	
	








	


	
	


      

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

Yes, they do release Oxygen, in the form of bubbles, when placed in water (normally a live bait tank for minnows).  I made a small airtight container with a connection to my normal bubbler hose, filled it 3/4 full of water, dropped in a tab, sealed the container, and waited - -  and the result I had was there were barely any bubbles being released from the tab.  I bought a couple of tabs off ebay - perhaps they were old and degraded.  I'm not sure how much (if any) the tablets are supposed to "fizz".  The tablets are available new for 79 cents each, but they only come in a box of 18 cards, two tabs per card, at that price. I didn't want to get an entire box only to find out my scheme would not work.  

I really thought if they released enough Oxygen that it would speed up regeneration -  and eliminate the need to add peroxide.

Ken 

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan <stefan_trethan@...> wrote:

>
> Are they supposed to release oxygen in gaseous form?  Maybe they work
> differently.
> 
> ST
> 
> On Fri, Jul 10, 2009 at 7:05 PM, Ken Stuempges<ozarkshermit@...> wrote:
> > Well - I had to try it at least . . .
> > The Oxygen tabs I tried did not generate enough oxygen to make many bubbles in the tank.  Perhaps the tabs were old, but I doubt if new ones would have been much better.
> >
> > Ken
> >
>

How about electrolysis?

I experimented with etchant regeneration by electroplating before
(carbon welding rod electrodes) and got copper plated from the CuCl,
but there was also some gas created (probably hydrogen, oxygen, and
chlorine). I abandoned the experiments, but later we discussed the
possibility of using the gasses for regeneration, maybe with a
downstream reactor or some other means to improve efficiency.

You could also electrolyse clean saline solution externally and pipe
the oxygen and chlorine into the etcher, preferably taking care not to
ignite the gasses (should be safe if the gas volume is kept low). But
it seems appealing to electrolyse the etchant and remove some excess
copper in the process.

What's up with google mail spell checker? It highlights correct words,
and when I click them I get exactly the same word in the suggestion
list...... stupid thing.

ST

On Fri, Jul 10, 2009 at 7:31 PM, Ken Stuempges<ozarkshermit@...> wrote:
> Yes, they do release Oxygen, in the form of bubbles, when placed in water (normally a live bait tank for minnows).  I made a small airtight container with a connection to my normal bubbler hose, filled it 3/4 full of water, dropped in a tab, sealed the container, and waited - -  and the result I had was there were barely any bubbles being released from the tab.  I bought a couple of tabs off ebay - perhaps they were old and degraded.  I'm not sure how much (if any) the tablets are supposed to "fizz".  The tablets are available new for 79 cents each, but they only come in a box of 18 cards, two tabs per card, at that price. I didn't want to get an entire box only to find out my scheme would not work.
>
> I really thought if they released enough Oxygen that it would speed up regeneration -  and eliminate the need to add peroxide.
>
> Ken

On Fri, 2009-07-10 at 20:09 +0200, Stefan Trethan wrote:
> How about electrolysis?
> 
> I experimented with etchant regeneration by electroplating before
> (carbon welding rod electrodes) and got copper plated from the CuCl,
> but there was also some gas created (probably hydrogen, oxygen, and
> chlorine).
> 

I don't think you get copper plated from the CuCl, just some removable
wet deposit around the cathode. But i want to say something about
chlorine gas use from HCl/CuCl electrolysis. I believe (but still not
convinced) that found a simple way of doing this. But only for bubbling
the resulting gas in to the CuCl etchant.

The idea is use the old saturated CuCl to produce chlorine and oxygen to
the new etchant while some copper gets deposited. Using a 'Hofmann
voltameter' type of container to separate the Chlorine/oxygen gas from
the hydrogen gas. See http://en.wikipedia.org/wiki/Hofmann_voltameter

This 'Hofmann voltameter' was to make water electrolysis where both
gases were collected in two different places. It can be made really
simple by just using the normal etching plastic container and just a
large vertical plastic tube inside the bath closed on top and with the
anode on bottom. One rubber tube will leave the chlorine/oxygen gas to
the etchant container. And the hydrogen gas will go to open air.

Using HCl or CuCl if water electrolysis occurs the oxygen will also be
on the anode. So no need of fine tune the voltage or current since both
gases are positive for the CuCl regeneration.

I use to buy 25% HCl in 1L. But one time i ask for a 5L container they
give me HCl in 37% because it was the only they have in 5L. That thing
was really gaseous. I believe that if i bubble air in 37% closed
container and the a tube leave the gas to the etchant i will get big
amount of chlorine in to the etchant. But electrolysis should work at
lower concentrations. 

Big pcb shops seems to use a copper electrowinning process for CuCl,
using a ion exchange membrane. And there is some processes to get
chlorine gas from HCl using a proton membrane, were the hydrogen is
mixed with air oxygen to get water. The only thing I found to be simple
to do was this 'Hofmann voltameter', from which i expect critics.

> Using HCl or CuCl if water electrolysis occurs the oxygen will also be
> on the anode. So no need of fine tune the voltage or current since both
> gases are positive for the CuCl regeneration.

Forgot to say that graphite and maybe lead can be used as anode and
maybe stainless steel can also be used as cathode.

Simao Cardoso wrote:
> 
> 
> 
> 
>  > Using HCl or CuCl if water electrolysis occurs the oxygen will also be
>  > on the anode. So no need of fine tune the voltage or current since both
>  > gases are positive for the CuCl regeneration.
> 
> Forgot to say that graphite and maybe lead can be used as anode and
> maybe stainless steel can also be used as cathode.
> 

Common graphite welding rods deteriorate as gas evolves at the surface, 
breaking it away into small particles.

Stainless anodes will vanish in no time flat in CuCl.

Pb wouldn't last any time either as it converts to lead(II) chloride 
complex.


Adam

Titanium maybe?
Rods are fairly cheap I made part of my PCB holder out of it.

ST

On Mon, Jul 13, 2009 at 5:39 AM, Adam Seychell<a_seychell@...> wrote:
>
> Common graphite welding rods deteriorate as gas evolves at the surface,
> breaking it away into small particles.
>
> Stainless anodes will vanish in no time flat in CuCl.
>
> Pb wouldn't last any time either as it converts to lead(II) chloride
> complex.
>
>
> Adam
>

Stefan Trethan wrote:
> 
> 
> 
> Titanium maybe?
> Rods are fairly cheap I made part of my PCB holder out of it.
> 
> ST

Titanium is great stuff, but expensive. I made PCB holder too. Two 
pieces of 6mm rod cut 30mm long. One end of each rod I hack saw a slot 
about 20mm deep. The slots are modified so a 1.6mm PCB neatly slides in. 
At the opposite ends, I drill a centre hole and press fit a length of M4 
threaded steel rod. This provides a stud to fasten to my plastic holder 
with common steel nuts. The two titanium rods then stand perpendicular 
to a small piece of acrylic sheet, which on the opposite side, has a 
handle. The titanium has stood the test of time.


Titanium won't work as an anode. All you'll do is build up an oxide 
layer until it gets so thick, that the voltage required for electrolysis 
will be > 50 volts. i.e you just make an electric heater.

People who routinely do electrolysis in chloride solutions use titanium 
coated with a conductive precious metal oxides. try a google search

http://www.google.com.au/search?hl=en&safe=off&q=dimensionally+stable+anodes+&btnG=Search&meta=cr%3DcountryAU

On Mon, 2009-07-13 at 18:04 +1000, Adam Seychell wrote:

> Titanium is great stuff, but expensive. I made PCB holder too. Two 
> pieces of 6mm rod cut 30mm long. One end of each rod I hack saw a
> slot 
> about 20mm deep.

I think it's more common and better approach to use a 3 titanium rods
holder. The board is just pressed between the rods. The middle rod in
one side and the other two in the other board side. To press the board
you have a plastic piece with 3 holes where the rods are.  Moving the
plastic from the top to the board will press the board between the rods.
Very easy and efficient, simple to do and 5mm is enough to hold the
board. 

> Titanium won't work as an anode. All you'll do is build up an oxide 
> layer until it gets so thick, that the voltage required for
> electrolysis 
> will be > 50 volts. i.e you just make an electric heater.

There are platinum coated titanium anodes, the smaller ones are so
expensive. But i think even platinum won't last much years. So a hard
graphite rod from those used as drawing pencil should be the best try.
There is also the graphite rod inside bigger batteries, but disassembly
batteries it's not recommendable.

I think of stainless steel for cathode only. Is still a no do?

And the overall process it worth any try?

Simao Cardoso wrote:
> 
> There are platinum coated titanium anodes, the smaller ones are so
> expensive. But i think even platinum won't last much years. So a hard
> graphite rod from those used as drawing pencil should be the best try.
> There is also the graphite rod inside bigger batteries, but disassembly
> batteries it's not recommendable.
> 
> I think of stainless steel for cathode only. Is still a no do?
> 
Stainless cathode might be ok while being plated, because the negative 
potential will stop oxidation.

I've heard platinum anodes are no good either in chloride, they slowly 
corrode. Anyway, like I said earlier, people normally use metal oxide 
coated anodes for chlorine oxidation. You should be able to buy small 
metal oxide coated titanium anodes. In Melbourne, Australia I know of a 
place that makes you these anodes. I remember reading an article on the 
web on how to make your own lead(II) oxide anodes on a titanium substrate.

yea, this is it I think:
http://www.geocities.com/CapeCanaveral/Campus/5361/chlorate/leaddiox/leaddioxide.html

On Tue, 2009-07-14 at 17:14 +1000, Adam Seychell wrote:
> I've heard platinum anodes are no good either in chloride, they slowly
> corrode. I remember reading an article on the web on how to make your
> own lead(II) oxide anodes on a titanium substrate.


Adam, Thanks for the high value and expert suggestions. 
But this all ideia don't worth your time, the time off the thousands of
people that subscribe this list, or mine. 

I wish this to give a right 'disposal' to the etchant, not so much for
the regeneration, air works good for me. I thought that will need to
split the hydrogen from the oxygen or chlorine, otherwise i will be
moving water or HCl at high energy expense. The ideia will work nice in
that field, could be used a water bottle, a inverted syringe (easy to
fit a tube) or a glue tube or a silicone sealant package, to grab the
gas. But there is no oxygen/chlorine bubbles at all!

The machines used in copper electrowinning from CuCl use 1000A or more
currents with just little kg/hour of copper. A CuCl bath has very high
conductivity. But worst CuCl electrolysis is said to be one off the most
efficient for hydrogen production (at high temperature). This is a
energy waste.

I tested the most powerful psu i have: a 24V 14A switched mode one. Ok i
also have a 12v 60A  (it says 300A peak in the package and i have
already modified it for better) as huge battery charger, and various
mono/bi/three-fase welding machines. But used the cnc stepper motor psu,
it has current limit. For electrodes was just copper wire because its
copper and i wont damage the etcher. The psu went down to 8V so it was
at 14A. I got some small bubbles ONLY in the CATHODE and judging by the
color I got a non solid deposit of copper oxide (red).

>From a CuCl electrolisys paper i got this equation and I added the water
and copper oxide.

2CuCl(aq) + 2HCl(aq) + H20(aq) + ?e- -> 2CuCl2(aq) + CuO (aq) + 2H2(g)

So this could be a process off getting copper from there since copper
oxide and sulfuric acid give copper sulphate. Or a way to inicialize the
CuCl etchant from HCl and copper scrap with a psu (without any H2O2). 
Or just to spend the etchant without etching anything :>
And with high energy cost.
But NOT for making chlorine gas! 

Sorry for wasting your time. It seems the original thread author already
has a much efficient ideia for regeneration :)




PS
> There are platinum coated titanium anodes, the smaller ones are so
> > expensive.

I wanted to say here: 'the smaller ones are NOT so expensive.'