Homebrew PCBs

Last night I added 1 litre of HCl (30.5%) to 2 litres of distilled
water to make 12 litres of 10% etchant (to start off with) in my
plastic Coleman cooler tank. To this I added 1.8 kg of clean copper
wire I had washed in dish detergent and hot water.

Twelve hours later, the copper covered with the acid solution looks
unchanged. About half the wire, which is pieces about 12" long bent
into different shapes, (so the copper is a large jumble), sticks out
of the solution. Most of this is covered by a pink coloured, hazy
looking film.

I don't know what to expect, but so far this is what I have noted.

Grant

If you have followed my last posts you may have read the H2O2 adding method is somewhat similar to what 
you want to do. It may be helpful in making the starting solution (i'm not sure if your method will 
work). I can't figure out why my etchant immediately starts working fast when new (only hcl h2o2 and 
h2o) and plain hcl does work so slow. In which manner works the h2o2 generating CuCl2 (or Cu2Cl) from 
plain Copper?


I really believe if you pour in some H2O2 you would get a useable solution immediately (Which can from 
then be regenerated by air oxygen), but i don't know if you get CuCl2 by using the buildup on the air 
exposed copper. I also don't understand why you should wait until "fumes" and air have done their work, 
won't it produce the same think if startig the bubbler but faster?

You see my understanding of chemistry is quite poor but i really want to figure out how this works and 
you can be sure i won't annoy you all.


kind regards

Stefan

*ggg* i find it funny you make 12(twelve) liters of fluid by mixing 1 and 2  ;-) ... 

please don't misunderstand me, i'm really curios about what will happen to your etchant...
please continue with the copper dissolving this way, it would be a really nice and cheap way.. 



13.04.2003 20:14:05, "grantfair2001" <grant.fair@...> wrote:

>Last night I added 1 litre of HCl (30.5%) to 2 litres of distilled
>water to make 12 litres of 10% etchant (to start off with) in my
>plastic Coleman cooler tank. To this I added 1.8 kg of clean copper
>wire I had washed in dish detergent and hot water.
>
>Twelve hours later, the copper covered with the acid solution looks
>unchanged. About half the wire, which is pieces about 12" long bent
>into different shapes, (so the copper is a large jumble), sticks out
>of the solution. Most of this is covered by a pink coloured, hazy
>looking film.
>
>I don't know what to expect, but so far this is what I have noted.
>
>Grant
>
>
>
>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/ 
>
>
>

Hi Stefan -

I really don't understand the chemistry; Adam is quite knowlegeable
about it. There is some information on the chemistry in this article:

http://www.dnai.com/~rexa/Projects/CuCl_ech.html 

You are right, I should have said I added one 4 litre jug of Hcl to
two 4 litre jugs of distilled water to get 12 litres of etchant.
(There is a limit to "the magic of chemistry" <g>)

Grant

yes, thanks, i read the page several times.

my problem isn't understanding the particular process, i have a severe lack of common chemistry 
knoweledge. i do understand the particular formulars but i don't know which factors have to apply to get 
such a reaction actually going on. (e.g. i dont understand what happens within my HCl H2O2 bath where 
initially there is zero CuCl2 but it too works immediately). I simply don't know why this happens....


sorry that i didn't figure that out more clearly..


regards

stefan

You should put full 1.8kg of the wire in. I takes about 24 hours 
for the acid to really start going dark and cuprous/cupric 
chloride mix to be produced. The copper in the air should 
eventually go bright blue Cu(OH)2 coating.
Has the HCl still changed from its normal pale yellow to a dark 
brown ?. If so then its working. This reaction is an accelerating 
one.
I'm sorry if I misguided you and you feel its not working as 
expected. I've made 2 batches so far, using this technique.
Eventually I would like to write a web page giving much more 
accurate information than I have done so in these posts, 
including pictures. I'm still experimenting myself at this stage.

Just add concentrated acid from now on, there should be enough 
water for the moment. Don't hesitate to ask any questions.

Adam


grantfair2001 wrote:

> Last night I added 1 litre of HCl (30.5%) to 2 litres of distilled
> water to make 12 litres of 10% etchant (to start off with) in my
> plastic Coleman cooler tank. To this I added 1.8 kg of clean copper
> wire I had washed in dish detergent and hot water.
> 
> Twelve hours later, the copper covered with the acid solution looks
> unchanged. About half the wire, which is pieces about 12" long bent
> into different shapes, (so the copper is a large jumble), sticks out
> of the solution. Most of this is covered by a pink coloured, hazy
> looking film.
> 
> I don't know what to expect, but so far this is what I have noted.
> 
> Grant
> 
> 
> 
> 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/ 
> 
>

Hi Adam- I was not feeling mislead, I just did not know what to expect.

The copper has only been in the acid for 18 hours. The acid still
looks  clear, as it did when I poured it into the water. The copper in
the air looks much as it did at the time of my last post. 

I hadn't measured the room temperature when I wrote the above, so I
went and did this. The etchant temperature is  about 65 deg. F. 

As I measured the temperature, before my very eyes on several spots on
the exposed copper wire a turquoise blue coating appeared. That was
quite amazing!  So I have every reason to believe that things will
unfold as they have for you.

The tank has been covered with its cover, which has a 9/16" hole in
it. Does this process need lots of air exposure at first? Or was it
just coincidence that when I took the lid off to take the temperature
the process evidenced itself?

I did put the entire 1.8 kg of copper in at the start.

Thanks for your continuing advice, information, and encouragement. I
will keep the list posted about the progress of the etchant.

Grant

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
<adam_seychell@y...> wrote:

> You should put full 1.8kg of the wire in. I takes about 24 hours 
> for the acid to really start going dark and cuprous/cupric 
> chloride mix to be produced. The copper in the air should 
> eventually go bright blue Cu(OH)2 coating.
> Has the HCl still changed from its normal pale yellow to a dark 
> brown ?. If so then its working. This reaction is an accelerating 
> one.
> I'm sorry if I misguided you and you feel its not working as 
> expected. I've made 2 batches so far, using this technique.
> Eventually I would like to write a web page giving much more 
> accurate information than I have done so in these posts, 
> including pictures. I'm still experimenting myself at this stage.
> 
> Just add concentrated acid from now on, there should be enough 
> water for the moment. Don't hesitate to ask any questions.
> 
> Adam

I took the easy way out and just bought CuCl2 powder. But if I were to
do it the way you're doing, I would imagine that bubbling air through
the solution would speed the reaction. It would add fresh oxygen 
and also agitate the solution - thus flushing the oxidized material
from the surface of the copper wire as it reacts.

An aquarium pump, some tubing, and some airstones can be purchased
from the local pet store for about $10 total.

~Rolan

--- In Homebrew_PCBs@yahoogroups.com, "grantfair2001"
<grant.fair@s...> wrote:

> Hi Adam- I was not feeling mislead, I just did not know what to expect.
> 
> The copper has only been in the acid for 18 hours. The acid still
> looks  clear, as it did when I poured it into the water. The copper in
> the air looks much as it did at the time of my last post. 
> 
> I hadn't measured the room temperature when I wrote the above, so I
> went and did this. The etchant temperature is  about 65 deg. F. 
> 
> As I measured the temperature, before my very eyes on several spots on
> the exposed copper wire a turquoise blue coating appeared. That was
> quite amazing!  So I have every reason to believe that things will

Opps, I forgot of mentioned that the reaction needs lots of 
atmospheric air !. keep the container open.
Copper doesn't react with HCl acid by its self. There is probably 
a complex oxidation process happening with the wetted copper, 
air, and HCl. I know that several copper compounds are made in a 
similar way. I once made copper acetate with vinegar and copper, 
but it took days just to get a tablespoon of the dried salt.

I actually had the container outside completely exposed (covered 
with a shade cloth to stop leaves blowing in), so I suppose 
that's why it seemed to work faster that what you are 
experiencing. You could of very well seen the formation of blue 
cupric hydroxide before your eyes. The oxygen starved environment 
was preventing it from happening before you removed the lid.


grantfair2001 wrote:

> Hi Adam- I was not feeling mislead, I just did not know what to expect.
> 
> The copper has only been in the acid for 18 hours. The acid still
> looks  clear, as it did when I poured it into the water. The copper in
> the air looks much as it did at the time of my last post. 
> 
> I hadn't measured the room temperature when I wrote the above, so I
> went and did this. The etchant temperature is  about 65 deg. F. 
> 
> As I measured the temperature, before my very eyes on several spots on
> the exposed copper wire a turquoise blue coating appeared. That was
> quite amazing!  So I have every reason to believe that things will
> unfold as they have for you.
> 
> The tank has been covered with its cover, which has a 9/16" hole in
> it. Does this process need lots of air exposure at first? Or was it
> just coincidence that when I took the lid off to take the temperature
> the process evidenced itself?
> 
> I did put the entire 1.8 kg of copper in at the start.
> 
> Thanks for your continuing advice, information, and encouragement. I
> will keep the list posted about the progress of the etchant.
> 
> Grant
> 
> --- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
> <adam_seychell@y...> wrote:
> 
>>You should put full 1.8kg of the wire in. I takes about 24 hours 
>>for the acid to really start going dark and cuprous/cupric 
>>chloride mix to be produced. The copper in the air should 
>>eventually go bright blue Cu(OH)2 coating.
>>Has the HCl still changed from its normal pale yellow to a dark 
>>brown ?. If so then its working. This reaction is an accelerating 
>>one.
>>I'm sorry if I misguided you and you feel its not working as 
>>expected. I've made 2 batches so far, using this technique.
>>Eventually I would like to write a web page giving much more 
>>accurate information than I have done so in these posts, 
>>including pictures. I'm still experimenting myself at this stage.
>>
>>Just add concentrated acid from now on, there should be enough 
>>water for the moment. Don't hesitate to ask any questions.
>>
>>Adam
> 
> 
> 
> 
> 
> 
> 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/ 
> 
>

Thanks for the quick response. 

The temperature here is just starting to warm up a bit; it was below
freezing last week. Spring has not quite arrived yet. So it will be
easier to take the lid off and keep the tank in the basement. There
are some iron/steel tools and nuts/bolts stored within 6 or 7 feet but
I assume short term exposure will not wreak havoc with them. I can
temporarily move them into another room if that is advisable. (List
members please advise!)

I had just moved the tank before I got your email and when I took the
lid off I thought maybe the blue bits had faded. So now it will be off
with the lid. Thanks again.

Grant

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
<adam_seychell@y...> wrote:

> Opps, I forgot of mentioned that the reaction needs lots of 
> atmospheric air !. keep the container open.
> Copper doesn't react with HCl acid by its self. There is probably 
> a complex oxidation process happening with the wetted copper, 
> air, and HCl. I know that several copper compounds are made in a 
> similar way. I once made copper acetate with vinegar and copper, 
> but it took days just to get a tablespoon of the dried salt.
> 
> I actually had the container outside completely exposed (covered 
> with a shade cloth to stop leaves blowing in), so I suppose 
> that's why it seemed to work faster that what you are 
> experiencing. You could of very well seen the formation of blue 
> cupric hydroxide before your eyes. The oxygen starved environment 
> was preventing it from happening before you removed the lid.

Luther - thanks for the hydrogen peroxide idea (and thanks to Rolan
for this also). I may try it tomorrow since I don't see much change
after 24 hours with the lid off the etch tank, except a few more blue
spots; maybe ten 1/4" long bits on the many copper wire above acid
level. I know someone who is a hairdresser and I think they have
access to inexpensive hydrogen peroxide so I'll see what concentration
it is and if its cheaper than drug store grade.

Grant

--- In Homebrew_PCBs@yahoogroups.com, luther m stroud <dukes500@j...>
wrote:

> I made my cucl like you with copper and hcl . adding some drug store
> hydrogen peroxide 3% on the bottle will help get it strarted .  the data
> on some graphs i was looking at said etch is best at 35c about 2,5 molar
> cucl  and  a saturated with sodium cloride also in that same bath of
> etchant. allows you to use less hcl.    wonder if you can heat the air
> you bubble to warm the solution  rather that cool it .  good luck with
> your etcher project.

I made my cucl like you with copper and hcl . adding some drug store
hydrogen peroxide 3% on the bottle will help get it strarted .  the data
on some graphs i was looking at said etch is best at 35c about 2,5 molar
cucl  and  a saturated with sodium cloride also in that same bath of
etchant. allows you to use less hcl.    wonder if you can heat the air
you bubble to warm the solution  rather that cool it .  good luck with
your etcher project.

Hi Grant.
How is the copper reaction going ? What color is the acid 
solution now ? Can you smell HCl when you put your noise in the 
container ?

I'm testing the procedure once again on small scale to get a 
better idea. I've got 12.3 grams of 0.7mm copper sheet about half 
immersed in 40 ml of 10% HCl, in a beaker. I'll let you know how 
it goes. Temperature here is 8\ufffdC (night) ~ 17\ufffdC (day).

For holding a PCB vertical I use a piece of 20 mm PVC electrical 
conduit. I cut a slit length ways into one end of the pipe using 
a wood hand saw. I heat the end up so its just a tad soft and 
push a piece of PCB material edge on into the slit. Then I 
immediately cool under water and it leaves an gap equal to the 
PCB width. It seems to make a tight fit with the PCB when cold. 
I'm getting a digital camera soon so I'll be able to take some 
pictures. Especially of the copper reactions in HCl.

The Rex web page mentions about horizontal etching being much 
better in terms of uniformity. I have never tried this method but 
I know from experience that vertical bubble etching does not 
produce good uniformity. The only disadvantage I can see in 
horizontal float etching is it being limited to single sided 
action which doubles your etch time. However, horizontal float 
etching may produce more aggressive agitation at the copper 
surface . I would imagine bubble distribution is critical.

Adam



grantfair2001 wrote:

> Luther - thanks for the hydrogen peroxide idea (and thanks to Rolan
> for this also). I may try it tomorrow since I don't see much change
> after 24 hours with the lid off the etch tank, except a few more blue
> spots; maybe ten 1/4" long bits on the many copper wire above acid
> level. I know someone who is a hairdresser and I think they have
> access to inexpensive hydrogen peroxide so I'll see what concentration
> it is and if its cheaper than drug store grade.
> 
> Grant
> 
> --- In Homebrew_PCBs@yahoogroups.com, luther m stroud <dukes500@j...>
> wrote:
> 
>>I made my cucl like you with copper and hcl . adding some drug store
>>hydrogen peroxide 3% on the bottle will help get it strarted .  the data
>>on some graphs i was looking at said etch is best at 35c about 2,5 molar
>>cucl  and  a saturated with sodium cloride also in that same bath of
>>etchant. allows you to use less hcl.    wonder if you can heat the air
>>you bubble to warm the solution  rather that cool it .  good luck with
>>your etcher project.
> 
> 
> 
> 
> 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/ 
> 
>

Hi Adam-

I took the lid off the tank as planned 2 nights ago. By noon today I
saw little change. The etchant was clear, the copper wire in the
etchant was shiny and looked just as it did before it went in, and the
wire above the etchant surface is a bit more covered with a cloudy
film a bit darker shade of copper than the shiny wire. There was a bit
more blue stuff on the copper, but this might cover 5% at most.

So, today at noon I added about 1/2 litre HCl to the tank. I did pour
it over the wire which was exposed. Much the of the blue color turned
dark brown. The etchant took on a very light shade of green. It was so
light that I wasn't sure whether I was imagining that.

Tonight I got a half litre of 3% hydrogen peroxide. Almost immediately
upon pouring it in, the green color became much more distinct, a
substantially darker shade which was a clear but unmistakable green. 

I then added some more 30.5% HCL. By now I have added roughly 2 litres
more acid to the original tankful of 10% HCl. The etchant darkened
some more still; it is still that clear green color. For the first
time I saw that the copper wire in the etchant was changing color. Most
of the wire under the etchant became a dark grey or brown color with a
dull texture; some was a lighter grey.

When I poured the last glugs of HCL I did not need to put my nose in
the conbtainer- it was briefly fuming around the area I had poured the
acid in, all in one spot. This stopped in under a minute.

I had a source (Cole Parmer- LabCo) for a hydrometer with .002
divisions, from Sp Gr 2.00 to 4.25 for C$16.00. However, they charge
an extra $25 for orders under $100, so I have been looking elsewhere,
hoping that I would find a better deal, but no luck to date. In
addition I learned that chemicals are not carried By COle Parmer here,
although they do in the U.S. So I haven't checked the copper
concentration in the etchant. 

Anyone in Canada want to go in together on a Cole Parmer order so we
can spend $100 on eqipment and save that 25$ add on?

I assume the process is working o.k. What do ya think? Can I add more
hydrogen peroxide (if I can get it cheaply - at $3 for 450 mL the
drugstore stuff is too expensive) and/or acid?

Grant

--- In Homebrew_PCBs@yahoogroups.com, Adam Seychell
<adam_seychell@y...> wrote:

> Hi Grant.
> How is the copper reaction going ? What color is the acid 
> solution now ? Can you smell HCl when you put your noise in the 
> container ?
> 
> I'm testing the procedure once again on small scale to get a 
> better idea. I've got 12.3 grams of 0.7mm copper sheet about half 
> immersed in 40 ml of 10% HCl, in a beaker. I'll let you know how 
> it goes. Temperature here is 8°C (night) ~ 17°C (day).
> 
> For holding a PCB vertical I use a piece of 20 mm PVC electrical 
> conduit. I cut a slit length ways into one end of the pipe using 
> a wood hand saw. I heat the end up so its just a tad soft and 
> push a piece of PCB material edge on into the slit. Then I 
> immediately cool under water and it leaves an gap equal to the 
> PCB width. It seems to make a tight fit with the PCB when cold. 
> I'm getting a digital camera soon so I'll be able to take some 
> pictures. Especially of the copper reactions in HCl.
> 
> The Rex web page mentions about horizontal etching being much 
> better in terms of uniformity. I have never tried this method but 
> I know from experience that vertical bubble etching does not 
> produce good uniformity. The only disadvantage I can see in 
> horizontal float etching is it being limited to single sided 
> action which doubles your etch time. However, horizontal float 
> etching may produce more aggressive agitation at the copper 
> surface . I would imagine bubble distribution is critical.
> 
> Adam

grantfair2001 wrote:
> Hi Adam-
> 
> I took the lid off the tank as planned 2 nights ago. By noon today I
> saw little change. The etchant was clear, the copper wire in the
> etchant was shiny and looked just as it did before it went in, and the
> wire above the etchant surface is a bit more covered with a cloudy
> film a bit darker shade of copper than the shiny wire. There was a bit
> more blue stuff on the copper, but this might cover 5% at most.

Thanks for letting us know what's happening. I don't remember it 
being that slow, I think the solution goes dark in 1st 2 days. 
But I'm testing the process more thoroughly to find out more. I'm 
not sure why it seems to not be working for you. Maybe I should 
of been 110% sure of my self before giving out instructions. 
There's no need to buy a hydrometer or any more expensive 
glassware just yet. I haven't worked out the optimum density 
range yet. I would hate for to buy anything becasue of my 
recommendation and find out later that it was not needed or the 
worng item.

The H2O2 will get things moving along. try bubbling air through 
the soltuion for a few hours and see what color change to the 
solution. If you see white film form on the copper that can 
easily wash off then thats copper(I) chloride. The blue stuff is 
copper (II) hydroxide and will dissolve in the excess HCl 
instandly to form copper(II) chloride.

seems to work fine already?

i guess if you let open the lid from now on and start bubbling when gets brown all may get fine without 
H2O2. but it may also be a good idea to measure the acid level (not ending up with 80% acid which you have 
to dilute, and not haveing to little acid in it)..

The H2O2 maybe is cheaper if you buy 30% stuff..
I will immediately ask a friend who has conections to some haircutting people...
The H2O2 was used to brighten hair, don't know if also used now.
I will ash for the price and concentration, maybe if it is ok you may also get it at your site...


I was told H2O2 is a bit volatile so keeping bigger amounts in bottles is not very good.. don't know if 
true...


regards

st