Homebrew PCBs

Hi guys I'm new using the homebrew mix of HCL 30% and H2O2 3%, and 
would like to know what is the best temperature for good etch time??? , 
right now when i do a fresh mix, the etch time is really fast around 5 
minutes , but if a week later i want to reuse that mix now clear green 
color my etch time goes up to more than 30 minutes!!!!!! 

Thanks

Bruno

----- Original Message ----- 

From: "Bruno St-Laurent" <bsl88k@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, January 03, 2006 2:48 PM
Subject: [Homebrew_PCBs] CUCL Temperature , etch time ?????


> Hi guys I'm new using the homebrew mix of HCL 30% and H2O2 3%, and
> would like to know what is the best temperature for good etch time??? ,
> right now when i do a fresh mix, the etch time is really fast around 5
> minutes , but if a week later i want to reuse that mix now clear green
> color my etch time goes up to more than 30 minutes!!!!!!

It should be blue for proper etching. You need to add some concentrated 
H2O2, to oxidise the green cuprous chloride to cupric chloride. Adding the 
3% H2O2 will make the solution too dilute. Or, just mix it fresh each time.

Leon 

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On Tue, 03 Jan 2006 15:48:13 +0100, Bruno St-Laurent <bsl88k@...>  
wrote:

> Hi guys I'm new using the homebrew mix of HCL 30% and H2O2 3%, and
>
> would like to know what is the best temperature for good etch time??? ,
>
> right now when i do a fresh mix, the etch time is really fast around 5
>
> minutes , but if a week later i want to reuse that mix now clear green
>
> color my etch time goes up to more than 30 minutes!!!!!!
>
>
> Thanks
>
>
> Bruno

It is problematic to heat this etchant because HCL will boil at like 50C  
or something, and already below this temperature the amount of produced  
fumes will increase greatly. So there probably isn't much to heat above  
room temperature before things get nasty.

Use a bubbler.

You do know that you need fresh H2O2 each time, as long as your Cu levels  
are still low?

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Tue, 03 Jan 2006 15:48:13 +0100, Bruno St-Laurent <bsl88k@n...>  
> wrote:
> 
> > Hi guys I'm new using the homebrew mix of HCL 30% and H2O2 3%, and
> >
> > would like to know what is the best temperature for good etch 
time??? ,
> >
> > right now when i do a fresh mix, the etch time is really fast 
around 5
> >
> > minutes , but if a week later i want to reuse that mix now clear 
green
> >
> > color my etch time goes up to more than 30 minutes!!!!!!
> >
> >
> > Thanks
> >
> >
> > Bruno
> 
> It is problematic to heat this etchant because HCL will boil at 
like 50C  
> or something, and already below this temperature the amount of 
produced  
> fumes will increase greatly. So there probably isn't much to heat 
above  
> room temperature before things get nasty.
> 
> Use a bubbler.
> 
> You do know that you need fresh H2O2 each time, as long as your Cu 
levels  
> are still low?
> 
> ST
>
I do use a bubbler !!!, ok, then i need to get concentrated H2O2!! is 
it easily available ???

On Tue, 03 Jan 2006 16:37:32 +0100, Bruno St-Laurent <bsl88k@...>  
wrote:

>
>
> I do use a bubbler !!!, ok, then i need to get concentrated H2O2!! is
>
> it easily available ???


Yes, and not very expensive either. You want some around 30%.
I was afraid the london bombings might cause more restrictions on H2O2,  
but so far i have not heard of any such thing.

ST

On Tue, 03 Jan 2006 16:24:52 +0100, Leon Heller  
<leon.heller@...> wrote:

> It should be blue for proper etching. You need to add some concentrated
>
> H2O2, to oxidise the green cuprous chloride to cupric chloride. Adding  
> the
>
> 3% H2O2 will make the solution too dilute. Or, just mix it fresh each  
> time.
>
>
> Leon


NO, not BLUE! It should be green. If it is blue you have no HCl and it  
can't etch.

ST

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, January 03, 2006 4:17 PM
Subject: Re: [Homebrew_PCBs] CUCL Temperature , etch time ?????


> On Tue, 03 Jan 2006 16:24:52 +0100, Leon Heller  
> <leon.heller@...> wrote:
> 
>> It should be blue for proper etching. You need to add some concentrated
>>
>> H2O2, to oxidise the green cuprous chloride to cupric chloride. Adding  
>> the
>>
>> 3% H2O2 will make the solution too dilute. Or, just mix it fresh each  
>> time.
>>
>>
>> Leon
> 
> 
> NO, not BLUE! It should be green. If it is blue you have no HCl and it  
> can't etch.

You are right, of course. I just checked some of mine and it is green.

Leon

H2O2 is available at beauty supply stores in concentrations up to 
40%. (It's hair bleach.) It's sold in 1 quart bottles for US$5 or 
so. I get mine at Sally Beauty Supply. Some beauty supply shops only 
sell to licensed hair stylists but some, like Sally, do sell to the 
general public. 

Buying in small quantities shouldn't raise any red flags. I don't 
think I'd want to try buying a 55 gallon drum of it, though. :=)


Regards, Bob


--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
On Tue, 03 Jan 2006 16:37:32 +0100, Bruno St-Laurent <bsl88k@n...>  
> wrote:
> 
> >
> >
> > I do use a bubbler !!!, ok, then i need to get concentrated 
H2O2!! is
> >
> > it easily available ???
> 
> 
> Yes, and not very expensive either. You want some around 30%.
> I was afraid the london bombings might cause more restrictions on 
H2O2,  

> but so far i have not heard of any such thing.
> 
> ST
>

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Tue, 03 Jan 2006 16:37:32 +0100, Bruno St-Laurent <bsl88k@n...>  
> wrote:
> 
> >
> >
> > I do use a bubbler !!!, ok, then i need to get concentrated 
H2O2!! is
> >
> > it easily available ???
> 
> 
> Yes, and not very expensive either. You want some around 30%.
> I was afraid the london bombings might cause more restrictions on 
H2O2,  
> but so far i have not heard of any such thing.
> 
> ST
>
Stefan how much H2O2 do i add ????

Bruno

----- Original Message ----- 

From: "Bob_xyz" <bob_barr@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Tuesday, January 03, 2006 4:37 PM
Subject: [Homebrew_PCBs] Re: CUCL Temperature , etch time ?????


> H2O2 is available at beauty supply stores in concentrations up to
> 40%. (It's hair bleach.) It's sold in 1 quart bottles for US$5 or
> so. I get mine at Sally Beauty Supply. Some beauty supply shops only
> sell to licensed hair stylists but some, like Sally, do sell to the
> general public.
>
> Buying in small quantities shouldn't raise any red flags. I don't
> think I'd want to try buying a 55 gallon drum of it, though. :=)

Mixed with acetone at freezing point it makes triacetone triperoxide. It's 
popular with suicide bombers.

Leon

On Tue, 03 Jan 2006 17:40:03 +0100, Bruno St-Laurent <bsl88k@...>  
wrote:

>
>
> Stefan how much H2O2 do i add ????
>
>
> Bruno


Of the 30% stuff just a little bit. A spoon full or two (DO NOT USE  
METAL), 5ml or less i'd say. Basically the smallest amount i can pour with  
my H2O2 bottle. This regenerate enough etchant for one, maybe two or three  
boards, depending on size of course.

ST

If it fizzes, you added too much. It won't actually do any harm if you 
do put too much in. I normally fill the cap of the bottle up and tip 
that in. It seems to be about right for my tank.

Les

Stefan Trethan wrote:

>
>Of the 30% stuff just a little bit. A spoon full or two (DO NOT USE  
>METAL), 5ml or less i'd say. Basically the smallest amount i can pour with  
>my H2O2 bottle. This regenerate enough etchant for one, maybe two or three  
>boards, depending on size of course.
>
>ST
>
>
>Be s
>

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Tue, 03 Jan 2006 17:40:03 +0100, Bruno St-Laurent <bsl88k@n...>  
> wrote:
> 
> >
> >
> > Stefan how much H2O2 do i add ????
> >
> >
> > Bruno
> 
> 
> Of the 30% stuff just a little bit. A spoon full or two (DO NOT 
USE  
> METAL), 5ml or less i'd say. Basically the smallest amount i can 
pour with  
> my H2O2 bottle. This regenerate enough etchant for one, maybe two 
or three  
> boards, depending on size of course.
> 
> ST
>
Wow really small quantity !!! last question, Can it be regenarate for 
ever , or should be dispose after some H2O2 addition ???

Thanks 

Bruno

> Wow really small quantity !!! last question, Can it be regenarate for
> ever , or should be dispose after some H2O2 addition ???
>
> Thanks
>
> Bruno

You can use it indefinitely. Of course HCl is also used up, so you need to  
add that too after a while. You can either go by feel and add when it  
doesn't help to add H2O2, or you see any blue sludge on the PCB, or you  
can look in the links section on how to measure the molarity of HCl in the  
etchant. Look for the method with the two eyedroppers it is the only one  
sufficiently simple IMO. You might also want to get a hydrometer. It is  
used to measure density (amount of copper per volume). You can get one  
cheap and easy in the car tools store, it is used to measure battery  
fluid. Should cost well under 10$. Go for the type with the swimming  
hydrometer in a large glass pipette, not the small plastic rotating  
pointer one. But that's really only if you are curious about the etchant,  
it is not a requirement to make it work.

Now if we only keep to add stuff to the etchant it will of course grow in  
volume. This is very slow and is good because it dilutes the copper in  
more etchant, otherwise you will reach a point where the specific gravity  
gets too high. Should you get too much etchant at one point you'll have to  
dispose of some, but unless you make really many boards regularly the  
growth is barely noticeable.


You will find if you keep using your etchant it will gradually turn from  
HCl+H2O2 etching to CuCl etching, that means instead of "instantly" using  
and needing H2O2 to etch the H2O2 can be used to regenerate existing CuCl  
in the etchant. What that means for you is that once there is enough CuCl  
you do not necessarily need to add H2O2 each time. You only add it when  
the etchant turns from a bright green to a darker, brownish  color. If  
there is enough bright green regenerated etchant for the board there you  
do not need to add any H2O2, even if you last etched months ago. OTOH it  
will not help to add too much H2O2 - once all the etchant is bright green  
it does no good and will just decompose to useless oxygen that has nothing  
to regenerate and is released into the air.


*********

> If it fizzes, you added too much. It won't actually do any harm if youdo  
> put too much in. I normally fill the cap of the bottle up and tipthat  
> in. It seems to be about right for my tank.
> Les

if it fizzes it creates loads of nasty fumes that are corrosive. It's  
definitely too much if it does that.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> 
> > Wow really small quantity !!! last question, Can it be regenarate 
for
> > ever , or should be dispose after some H2O2 addition ???
> >
> > Thanks
> >
> > Bruno
> 
> You can use it indefinitely. Of course HCl is also used up, so you 
need to  
> add that too after a while. You can either go by feel and add when 
it  
> doesn't help to add H2O2, or you see any blue sludge on the PCB, or 
you  
> can look in the links section on how to measure the molarity of HCl 
in the  
> etchant. Look for the method with the two eyedroppers it is the 
only one  
> sufficiently simple IMO. You might also want to get a hydrometer. 
It is  
> used to measure density (amount of copper per volume). You can get 
one  
> cheap and easy in the car tools store, it is used to measure 
battery  
> fluid. Should cost well under 10$. Go for the type with the 
swimming  
> hydrometer in a large glass pipette, not the small plastic 
rotating  
> pointer one. But that's really only if you are curious about the 
etchant,  
> it is not a requirement to make it work.
> 
> Now if we only keep to add stuff to the etchant it will of course 
grow in  
> volume. This is very slow and is good because it dilutes the copper 
in  
> more etchant, otherwise you will reach a point where the specific 
gravity  
> gets too high. Should you get too much etchant at one point you'll 
have to  
> dispose of some, but unless you make really many boards regularly 
the  
> growth is barely noticeable.
> 
> 
> You will find if you keep using your etchant it will gradually turn 
from  
> HCl+H2O2 etching to CuCl etching, that means instead of "instantly" 
using  
> and needing H2O2 to etch the H2O2 can be used to regenerate 
existing CuCl  
> in the etchant. What that means for you is that once there is 
enough CuCl  
> you do not necessarily need to add H2O2 each time. You only add it 
when  
> the etchant turns from a bright green to a darker, brownish  color. 
If  
> there is enough bright green regenerated etchant for the board 
there you  
> do not need to add any H2O2, even if you last etched months ago. 
OTOH it  
> will not help to add too much H2O2 - once all the etchant is bright 
green  
> it does no good and will just decompose to useless oxygen that has 
nothing  
> to regenerate and is released into the air.
> 
> 
> *********
> 
> > If it fizzes, you added too much. It won't actually do any harm 
if youdo  
> > put too much in. I normally fill the cap of the bottle up and 
tipthat  
> > in. It seems to be about right for my tank.
> > Les
> 
> if it fizzes it creates loads of nasty fumes that are corrosive. 
It's  
> definitely too much if it does that.
> 
> ST
>
Thanks a lot for all these info !!!!, right now mine is bright clear 
green but etch really slowly, so i'll get H2O2 30% !!!!

Thanks

Bruno

On Tue, 03 Jan 2006 20:06:54 +0100, Bruno St-Laurent <bsl88k@...>  
wrote:

>
>
> Thanks a lot for all these info !!!!, right now mine is bright clear
>
> green but etch really slowly, so i'll get H2O2 30% !!!!
>
>
> Thanks
>
>
> Bruno
>


As long as there is not enough cucl in the tank even when bright green it  
will not etch well. But it will etch, very slowly, until it gets darker,  
which might be before the board is finished ;-).

ST

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan" 
<stefan_trethan@g...> wrote:
>
> On Tue, 03 Jan 2006 20:06:54 +0100, Bruno St-Laurent <bsl88k@n...>  
> wrote:
> 
> >
> >
> > Thanks a lot for all these info !!!!, right now mine is bright 
clear
> >
> > green but etch really slowly, so i'll get H2O2 30% !!!!
> >
> >
> > Thanks
> >
> >
> > Bruno
> >
> 
> 
> As long as there is not enough cucl in the tank even when bright 
green it  
> will not etch well. But it will etch, very slowly, until it gets 
darker,  
> which might be before the board is finished ;-).
> 
> ST
>

Stefan about the H2O2 30% , you really mean 30% not volume 30 ????

cause today i found H2O2 volume 30, it's only 9%!!!!!

Bruno

On Thu, 05 Jan 2006 23:33:14 +0100, Bruno St-Laurent <bsl88k@...>  
wrote:

>
>
> Stefan about the H2O2 30% , you really mean 30% not volume 30 ????
>
>
> cause today i found H2O2 volume 30, it's only 9%!!!!!
>
>
> Bruno
>


i dunno for sure, but i think it is 30% by volume not weight.

ST

----- Original Message ----- 

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Friday, January 06, 2006 12:40 AM
Subject: Re: [Homebrew_PCBs] Re: CUCL Temperature , etch time ?????


> On Thu, 05 Jan 2006 23:33:14 +0100, Bruno St-Laurent <bsl88k@...>
> wrote:
>
>>
>>
>> Stefan about the H2O2 30% , you really mean 30% not volume 30 ????
>>
>>
>> cause today i found H2O2 volume 30, it's only 9%!!!!!
>>
>>
>> Bruno
>>
>
>
> i dunno for sure, but i think it is 30% by volume not weight.

I think 30 vols means that it produces 30 x its volume as oxygen gas.

Leon

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" <leon.heller@b...> 
wrote:
>
<snip>
> 
> I think 30 vols means that it produces 30 x its volume as oxygen gas.
> 

Exactly. I just found that out today. Volume 20 is 6% H2O2, volume 30 
is 9%, and volume 40 is 12%. 

It's a bit better than the drugstore 3% strength but not by all that 
much.


Regards, Bob

--- In Homebrew_PCBs@yahoogroups.com, "Bob_xyz" <bob_barr@h...> wrote:
>
> --- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" 
<leon.heller@b...> 
> wrote:
> >
> <snip>
> > 
> > I think 30 vols means that it produces 30 x its volume as oxygen 
gas.
> > 
> 
> Exactly. I just found that out today. Volume 20 is 6% H2O2, volume 
30 
> is 9%, and volume 40 is 12%. 
> 
> It's a bit better than the drugstore 3% strength but not by all 
that 
> much.
> 
> 
> Regards, Bob
>
Ok guys , I finally found %35 H2O2 , and finding it was a lot easier 
that i tough , so guys if you need it , go to an Hydroponic Supply 
store , it's being use in fertilizer receipies !!!! in my area there 
a store like that in every city so i got 1000 ml bottle for $14.00 
canadian !!!!

Bruno

--- In Homebrew_PCBs@yahoogroups.com, "Bruno St-Laurent" <bsl88k@n...> 
wrote:
<snip>
> >
> Ok guys , I finally found %35 H2O2 , and finding it was a lot easier 
> that i tough , so guys if you need it , go to an Hydroponic Supply 
> store , it's being use in fertilizer receipies !!!! in my area there 
> a store like that in every city so i got 1000 ml bottle for $14.00 
> canadian !!!!
> 
> Bruno
>

Excellent. That sounds much better than the hair bleach with its 
significantly lower percentage. Now I've just got to find a hydroponic 
supply store.


Regards, Bob