Homebrew PCBs

(The first part is not my question -- just an account of my success  
with fabbing a PCB. Skip to the asterisks to see my real question.)

First off, thanks to everybody on this group and all the data thats  
been accumulated here. Last night I gave my first go and doing a  
toner transfer board and it went pretty well. My first try was with  
Office Depot photo paper, which didn't work at all. Then I ran out to  
Staples before they closed and got their glossy photo paper, it was a  
dollar under list price. The paper worked great and it took about 15  
minutes to go from plain board to transfered design. Then I mixed  
some Ferric Chloride from Datak powder and etched the board. I didn't  
heat the etchant but it was still pretty warm from mixing and took  
5-10 minutes to etch. For the first few minutes I just let it sit  
while I was busy doing something else, without much effect. Then I  
took a balled up paper towel and rubbed the board, not hard but  
pretty vigorously. This was a great way to do it, because it let me  
focus on the areas that needed it (around thermals the etchant was  
slower to work) without leaving the board in there so long that it  
undercut the traces. This morning I mixed up some Datak Tinnit and  
tinned the board. I don't have all the components yet but I did a  
solder a 20-DIP socket, v-reg, and a few capacitors to the board. It  
all went really well. I think my next one will be even better.

***

Anyway, this all has made me curious about the chemistry involved in  
etching and tinning. Namely, what exactly is Ferric Chloride, and how  
does it react with copper? I think its FeCl3, and it reacts with  
copper to make some sort of cupric chloride, but I'd really like to  
know the exact chemistry involved, if possible. Especially, what's  
left over after the board is etched, and what hazards do those  
chemicals represent?

Also, does anybody know how Tinnit works? It smells kind of bad,  
almost like sulfur...I just want to know what kind of chemicals I'm  
dealing with, how dangerous they are if they spill, evaporate, etc.  
Right now everything is stored in glass jars with plastic lids and  
clearly marked labels. In the case of the etchant, the jars are also  
labeled with "POISON" and a skull and cross bones and stored safely  
in the garage. No kids live here.

Finally, whats the best way to clean up after I'm done? The etchant  
and Tinnit are both acids, so it seems adding a base (like baking  
soda) would neutralize the acid, and then I could wash off in the  
utility sink in the garage. (Stains aren't a problem down there.) I  
haven't done that yet, because we do have copper pipes and I don't  
want to do any damage to the house. Notice I'm only talking about  
washing off in the sink, to dispose of the used chemicals (which I  
poured into separate jars in the hopes of reusing), I was planning on  
adding dry baking soda to both neutralize and solidify the etchant,  
then scooping it into a sealed plastic bag and putting it in the trash.

Thanks! Great group here!
Mark

Hi, thank you for posting this info... 
  do datak have a website where I can order? 

"Mark E. Haase" <mehaase@...> wrote:
  (The first part is not my question -- just an account of my success  
with fabbing a PCB. Skip to the asterisks to see my real question.)

First off, thanks to everybody on this group and all the data thats  
been accumulated here. Last night I gave my first go and doing a  
toner transfer board and it went pretty well. My first try was with  
Office Depot photo paper, which didn't work at all. Then I ran out to  
Staples before they closed and got their glossy photo paper, it was a  
dollar under list price. The paper worked great and it took about 15  
minutes to go from plain board to transfered design. Then I mixed  
some Ferric Chloride from Datak powder and etched the board. I didn't  
heat the etchant but it was still pretty warm from mixing and took  
5-10 minutes to etch. For the first few minutes I just let it sit  
while I was busy doing something else, without much effect. Then I  
took a balled up paper towel and rubbed the board, not hard but  
pretty vigorously. This was a great way to do it, because it let me  
focus on the areas that needed it (around thermals the etchant was  
slower to work) without leaving the board in there so long that it  
undercut the traces. This morning I mixed up some Datak Tinnit and  
tinned the board. I don't have all the components yet but I did a  
solder a 20-DIP socket, v-reg, and a few capacitors to the board. It  
all went really well. I think my next one will be even better.

***

Anyway, this all has made me curious about the chemistry involved in  
etching and tinning. Namely, what exactly is Ferric Chloride, and how  
does it react with copper? I think its FeCl3, and it reacts with  
copper to make some sort of cupric chloride, but I'd really like to  
know the exact chemistry involved, if possible. Especially, what's  
left over after the board is etched, and what hazards do those  
chemicals represent?

Also, does anybody know how Tinnit works? It smells kind of bad,  
almost like sulfur...I just want to know what kind of chemicals I'm  
dealing with, how dangerous they are if they spill, evaporate, etc.  
Right now everything is stored in glass jars with plastic lids and  
clearly marked labels. In the case of the etchant, the jars are also  
labeled with "POISON" and a skull and cross bones and stored safely  
in the garage. No kids live here.

Finally, whats the best way to clean up after I'm done? The etchant  
and Tinnit are both acids, so it seems adding a base (like baking  
soda) would neutralize the acid, and then I could wash off in the  
utility sink in the garage. (Stains aren't a problem down there.) I  
haven't done that yet, because we do have copper pipes and I don't  
want to do any damage to the house. Notice I'm only talking about  
washing off in the sink, to dispose of the used chemicals (which I  
poured into separate jars in the hopes of reusing), I was planning on  
adding dry baking soda to both neutralize and solidify the etchant,  
then scooping it into a sealed plastic bag and putting it in the trash.

Thanks! Great group here!
Mark


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

About the FeCl chemistry, try the links section.
I sure have seen pages describing the reaction, but i don't have any URLS.
If it isn't in the links try google. Shouldn't be too hard to find.


Tinnit _could_ be containing thiourea, which is a known carcinogenic  
substance. Don't mess about with it and you should be fine. I don't use it  
for that reason (i try to avoid anything over Xi rating). If anyone has a  
msds on tinit let me know.

cool-amp seems to be non-hazardous, but more expensive. I think i'd like  
to try that one day.

ST


On Fri, 02 Dec 2005 01:22:56 +0100, Mark E. Haase <mehaase@...>  
wrote:

>
>
> Also, does anybody know how Tinnit works? It smells kind of bad,
>
> almost like sulfur...I just want to know what kind of chemicals I'm
>
> dealing with, how dangerous they are if they spill, evaporate, etc.
>
> Right now everything is stored in glass jars with plastic lids and
>
> clearly marked labels. In the case of the etchant, the jars are also
>
> labeled with "POISON" and a skull and cross bones and stored safely
>
> in the garage. No kids live here.

Hi,

reading the cool-amp MSDS...

it consists of 40-50% table salt, 35-45% limestone, under 10% silver  
chloride, and the rest non-hazardous chemicals (secret).

It should not be impossible to make something similar.

I remember seeing on rough science (bbc) how they plated a mirror with  
silver using silver nitrate as one of the ingredients.

IMO that would be very interesting to look into further, silver chloride  
is much easier to get for me, and probably quite a bit cheaper.

ST

Did some reading, and found a german page that lists several plating and  
electroless plating recepies.
The relevant ones are:

Versilbern von Kupfer/Messing
(silver plating of copper/brass)
Zutaten:
(ingredients:)
10 g Silberchlorid
(10g silver chloride)
65 g Kaliumhydrogentartrat (=Weinstein)
(65g cream of tartar)
30 g Natriumchlorid (=Kochsalz)
(30g NaCl / table salt)
Wasser
(water)
Ansatz: Die Zutaten werden mit Wasser zu einem Brei anger\ufffdhrt.
(make-up: The ingredients are mixed to a paste.)
Hinweis: Die zu versilbernden Gegenst\ufffdnde werden damit abgerieben oder man  
l\ufffdsst den Brei darauf antrocknen. Mit Kreide wird nachgeputzt.
(Notice: Rub the items to be plated with it or let the paste dry on them.  
Polish with chalk.

second recepie:

Versilbern verschiedener Metalle
Zutaten:
(Silvering of various metals, ingredients:)
10 g Silbernitrat
(10g silver nitrate)
3,3 g Natriumchlorid
(3.3g NaCl/table salt)
10 g Kaliumhydrogentartrat (=Weinstein)
(10g cream of tartar)
20 g Schl\ufffdmmkreide
(20g 	precipitate chalk (calcium carbonate))
87 g Wasser
(87g water)
50 g Salmiakgeist
(50g 	spirits of ammonia / ammonia solution)

Ansatz: Das Silbernitrat wird in etwas Wasser gel\ufffdst. Getrennt davon wird  
das Kochsalz in etwas Wasser gel\ufffdst. Man vereinigt beide L\ufffdsungen und  
vermischt damit die restlichen Zutaten in einem M\ufffdrser.
(make-up: The silver-nitrate is solved in some water. Separate of it the  
table salt is solved in some water. Unite both and mix with the remaining  
ingredients in a mortar.)
Hinweis: Die Mischung darf keinem hellen Licht ausgesetzt werden.
(Notice: This mixture mustn't be exposed to bright light.)
Zum Versilbern wird der metallene Gegenstand mit Salmiakgeist gereinigt  
und mit einem wollenen Lappen, der mit der Mischung getr\ufffdnkt ist, gut  
gerieben, bis sich eine Silberschicht niedergeschlagen hat.
(To silver plate the item is cleaned with ammonia solution, and rubbed  
with a woolen rag saturated with the plating mixture until a silver layer  
is deposited.)
Eiserne Gegenst\ufffdnde m\ufffdssen vor dem Versilbern erst kurz in eine  
Kupfersulfatl\ufffdsung getaucht werden.
(Items made of iron must be dipped in a copper suplhate solution before  
silver plating.)

German instructions for those (and more) can be found at  
<http://\ufffdtzradierung.de/radierung/radihtm65.html>, translation courtesy of  
myself, no liability if i made a mistake ;-)


Notice the _impressive_ similarity with cool-amp, the silver compound,  
table salt, calcium carbonate, that's more or less it. Also, these are  
quite likely ancient recepies so there should be no legal issues like  
there would be when trying to copy cool-amp specifically.

I'm quite eager to try those, i'll be at my chemicals shop next week for  
sure! The first one seems easier to me.

While i'm OK satisfied with the solderpaste results i'd be more than happy  
to find a cold method for silver plating.
I'll let you know about what i find.

ST

>While i'm OK satisfied with the solderpaste results i'd be more than 
>happy to find a cold method for silver plating.

For what it's worth....I have a half bottle of Coolamp here, it was 
my "tinning" method of choice for a while. 4 to 5 year old tracks 
tinned with it now have a yellowish tint....Wouldn't waste my time on 
that again.

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

Datak says about Tinnit:

"4. After plating, the cirucit board will have chemical residues that will 
in time dull or corrode the plating. To neutralize and remove these 
residues, immerse and scrub the object in a mild solution of household 
ammonia, followed by running water rinse. Dry and polish with a paper 
towel."

FWIW.


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

From: "derekhawkins" <derekhawkins@...>
>
> For what it's worth....I have a half bottle of Coolamp here, it was
> my "tinning" method of choice for a while. 4 to 5 year old tracks
> tinned with it now have a yellowish tint....Wouldn't waste my time on
> that again.

If I were you I would not use ammonia. Mike

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>
> Datak says about Tinnit:
> 
> "4. After plating, the cirucit board will have chemical residues
that will 

> in time dull or corrode the plating. To neutralize and remove these 
> residues, immerse and scrub the object in a mild solution of household 
> ammonia, followed by running water rinse. Dry and polish with a paper 
> towel."
> 
> FWIW.
> 
> 
> ----- Original Message ----- 
> From: "derekhawkins" <derekhawkins@y...>
> >
> > For what it's worth....I have a half bottle of Coolamp here, it was
> > my "tinning" method of choice for a while. 4 to 5 year old tracks
> > tinned with it now have a yellowish tint....Wouldn't waste my time on
> > that again.
>

On Fri, 02 Dec 2005 16:21:27 +0100, derekhawkins <derekhawkins@...>  
wrote:

>
> For what it's worth....I have a half bottle of Coolamp here, it was
>
> my "tinning" method of choice for a while. 4 to 5 year old tracks
>
> tinned with it now have a yellowish tint....Wouldn't waste my time on
>
> that again


Ok, thanks.

I've mailed my chemicals shop 'bout the prices for silver chloride and  
silver nitrate and they put quite the dampener on the idea anyway. While  
it is probably very sparingly used it is still not cheap. Also, the layer  
is probably very, very thin. I guess it would be more economical if one  
would use "junk" silver and convert it into silver chloride with  
electrodes or to silver nitrate with acid. I guess plumbing solder is  
really the most economical way.

ST

On Fri, 02 Dec 2005 17:40:04 +0100, mikezcnc <eemikez@...> wrote:

> If I were you I would not use ammonia. Mike


Why?

ST

Why is that, Mike?

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

From: "mikezcnc" <eemikez@...>


> If I were you I would not use ammonia. Mike
> 
> --- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>>
>> Datak says about Tinnit:
>> 
>> "4. After plating, the cirucit board will have chemical residues
> that will

> Datak says about Tinnit:

I know. Have several unopened packs. Tinnit is probably the most 
cumbersome and expensive option in the long run. Another mixed bag 
of "chocolates". First time use of a fresh solution always produces the 
best results, it's all downhill after that.

--- In Homebrew_PCBs@yahoogroups.com, "Mike Young" <mikewhy@s...> wrote:
>

>While it is probably very sparingly used it is still not cheap.

Think I paid around $60.00 for a 4 oz jar of Coolamp several years ago. 
It's very expensive. But yes, it seems to last forever since very 
little is needed. Besides discolorations and unpredictable behavior in 
the case of Tinnit, another problem with this method of tinning is that 
you have no control over the thickness of the layer beyond the limit. 
There is no way you can beef up high current tracks for example. 
Neither can you hide pits and small holes.

Also, the solder paste method makes hand soldering SMD devices much 
easier. Just reflowing the solder on one pad usually fixes the device 
freeing up one hand to hold the solder and finish properly.


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

so if you use solderpaste reflow you don't tin the rest of the traces? won't 
they succumb to oxidation?

tnx
jim

----- Original Message ----- 
From: "derekhawkins" <derekhawkins@...>


Also, the solder paste method makes hand soldering SMD devices much
easier. Just reflowing the solder on one pad usually fixes the device
freeing up one hand to hold the solder and finish properly.

These silver formulae remind us of how early photographers had to make
the light sensitive emulsion, in a dark room, for their film or glass
plates.  

--- In Homebrew_PCBs@yahoogroups.com, "Stefan Trethan"
<stefan_trethan@g...> wrote:
>
> Did some reading, and found a german page that lists several plating
and  

> electroless plating recepies.
> The relevant ones are:
>

Run a roll of black and white film through some fixer solution (hypo).
 It will disolve the silver-based film emulsion.  If you know a
photographer who uses black and white film ask for a bottle of
exhausted fixer solution. You might even get some from a commerical,
custom film processor.  
> 
> I've mailed my chemicals shop 'bout the prices for silver chloride and  
> silver nitrate and they put quite the dampener on the idea anyway.
While  
> it is probably very sparingly used it is still not cheap. Also, the
layer  
> is probably very, very thin. I guess it would be more economical if
one  

> would use "junk" silver and convert it into silver chloride with  
> electrodes or to silver nitrate with acid. I guess plumbing solder is  
> really the most economical way.
> 
> ST
>

A color separation company or an offset printing company doing their own 
film or flat will also have the same kind of used fixer solution.

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

From: "bob_ledoux" <bobledoux@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, December 03, 2005 10:22 PM
Subject: [Homebrew_PCBs] Making Your Own Silver


> Run a roll of black and white film through some fixer solution (hypo).
> It will disolve the silver-based film emulsion.  If you know a
> photographer who uses black and white film ask for a bottle of
> exhausted fixer solution. You might even get some from a commerical,
> custom film processor.
>>
>> I've mailed my chemicals shop 'bout the prices for silver chloride and
>> silver nitrate and they put quite the dampener on the idea anyway.
> While
>> it is probably very sparingly used it is still not cheap. Also, the
> layer
>> is probably very, very thin. I guess it would be more economical if
> one
>> would use "junk" silver and convert it into silver chloride with
>> electrodes or to silver nitrate with acid. I guess plumbing solder is
>> really the most economical way.
>>
>> ST
>>
>
>
>
>
>
>
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/
> Yahoo! Groups Links
>
>
>
>
>
>