Homebrew PCBs

Hi, all
 
What is the best way to clean a PCB (remove solder flux) ?
 
I heard of 2 methods:
 
1-isopropyl alcohol bath with a temp. of 40 degrees Celsius.
 
2-Ultrasonic tank with appropriate cleaning product.
 
I had found some cheap ultrasonic tanks on ebay. Do I need to buy one or is
the first method good enough?
 
Thanks in advance
 
Joaquim
 
 
 
 
 
 


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

On Mon, 10 May 2004 17:49:46 +0100, Joaquim Boavida 
<jboavida@...> wrote:

>
> Hi, all
>
> What is the best way to clean a PCB (remove solder flux) ?
>
> I heard of 2 methods:
>
> 1-isopropyl alcohol bath with a temp. of 40 degrees Celsius.
>
> 2-Ultrasonic tank with appropriate cleaning product.
>
> I had found some cheap ultrasonic tanks on ebay. Do I need to buy one or 
> is
> the first method good enough?
>
> Thanks in advance
>
> Joaquim
>

I wonder if the first method produces a lot of noxious fumes?

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Monday, May 10, 2004 6:02 PM
Subject: Re: [Homebrew_PCBs] Question About PCB cleaning


> On Mon, 10 May 2004 17:49:46 +0100, Joaquim Boavida
> <jboavida@...> wrote:
>
> >
> > Hi, all
> >
> > What is the best way to clean a PCB (remove solder flux) ?
> >
> > I heard of 2 methods:
> >
> > 1-isopropyl alcohol bath with a temp. of 40 degrees Celsius.
> >
> > 2-Ultrasonic tank with appropriate cleaning product.
> >
> > I had found some cheap ultrasonic tanks on ebay. Do I need to buy one or
> > is
> > the first method good enough?
> >
> > Thanks in advance
> >
> > Joaquim
> >
>
> I wonder if the first method produces a lot of noxious fumes?

Cold IPA works OK for me, with a stiff brush.

Leon

Joaquim:

Use lacquer thinner. (I THINK that is amyl acetate?).  Dissolves the "rosin 
flux" as readily as water washes off sugar!

HOWEVER, it will damage molded plastic stuff made of such as styrene or 
acrylic.  Won't bother Delrin or PVC or Teflon or Bakelite (phenolics).


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

On Tue, 11 May 2004 01:46:29 EDT, <JanRwl@...> wrote:

> Joaquim:
>
> Use lacquer thinner. (I THINK that is amyl acetate?).  Dissolves the 
> "rosin
> flux" as readily as water washes off sugar!

How bad is rosin flux (colophony) really?
I have seen some pretty old boards, coated in colophony, and could not
see any problems.

Of course if you have high impedance circuits it might very well be a 
problem.
Not sure about HF properties either.
But i can assure you it does not do any harm to most circuits and i have 
yet
to see it corrode anything (quite the opposite).

Now, why should i wash it off?
I'd rather coat the whole pcb in colophony resin to protect it from 
corrosion.

ST

In a message dated 5/11/2004 1:12:59 AM Central Standard Time, 
stefan_trethan@... writes:
Now, why should i wash it off?
It's simply NASTY-looking!


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

--- In Homebrew_PCBs@yahoogroups.com, "Leon Heller" 
<leon_heller@h...> wrote:

...
> 
> Cold IPA works OK for me, with a stiff brush.
> 
> Leon

I much prefer a Lager but then you really shouldn't drink when 
cleaning flux off your boards...  



:)

On Tue, 11 May 2004 02:14:18 EDT, <JanRwl@...> wrote:

> In a message dated 5/11/2004 1:12:59 AM Central Standard Time,
> stefan_trethan@... writes:
> Now, why should i wash it off?

> It's simply NASTY-looking!


Only if you are NASTY-soldering!.

If you are able to do clean soldering and don't smear the iron around
on the board it can be as clean looking as it gets.

Some kinds of colophony tend to go browner at soldering than others.

ST

--- In Homebrew_PCBs@yahoogroups.com, "Joaquim Boavida" 
<jboavida@m...> wrote:
>  
> Hi, all
>  
> What is the best way to clean a PCB (remove solder flux) ?
>  
> I heard of 2 methods:
>  
> 1-isopropyl alcohol bath with a temp. of 40 degrees Celsius.



I use 90%, not the 70% stuff.

old toothbrush

room temperature.

do it soon after soldering, not the next day.  it removes easier when 
fresh.

Also, if you feel like, you can clean while you are in the middle of 
a board to inspect it.


Dave















>  
> 2-Ultrasonic tank with appropriate cleaning product.
>  
> I had found some cheap ultrasonic tanks on ebay. Do I need to buy 
one or is

> the first method good enough?
>  
> Thanks in advance
>  
> Joaquim
>  
>  
>  
>  
>  
>  
> 
> 
> [Non-text portions of this message have been removed]

In a message dated 5/11/2004 6:50:51 AM Central Standard Time, 
stefan_trethan@... writes:
If you are able to do clean soldering and don't smear the iron around on the 
board it can be as clean looking as it gets.
ST:   Sorry, but I disagree!  I can solder much more neatly and 
professionally by hand than 99% of those "out there" who know which end of a soldering iron 
goes in the hand, and which on the work, and that "melted yellow/brown goo" 
just is NOT as nice as a "washed off" board!  

True, for most things not expected to operate for more than a decade without 
being re-done, modified, repaired, salvaged, or trashed, for one or two, that 
goop makes little difference.  BUT if you make ten to 1000 small boards 
(hand-soldered, NOT "wave soldered") professionally (that means "for money"!), the 
washing-off, then spraying with thin clear spray is standard industry practice! 
 It is NOT difficult for a "home worker" to do, either!  Perhaps needs a bit 
of PRIDE...


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

st is NOT as nice as a "washed off" board!
>
> True, for most things not expected to operate for more than a decade 
> without
> being re-done, modified, repaired, salvaged, or trashed, for one or two, 
> that
> goop makes little difference.  BUT if you make ten to 1000 small boards
> (hand-soldered, NOT "wave soldered") professionally (that means "for 
> money"!), the
> washing-off, then spraying with thin clear spray is standard industry 
> practice!

That's the point, it is not better at all, it might just look a bit better.
As you say, if the one that is going to pay for it likes it more washed 
off then
he should get it.

There is solder which leaves flux which is CLEAR. certainly less yellow
than the board you are working on.

>  It is NOT difficult for a "home worker" to do, either!  Perhaps needs a 
> bit
> of PRIDE...
>

well, you can certainly overdo it with that last one you know...

ST

> >  It is NOT difficult for a "home worker" to do, either!  Perhaps 
needs a 
> > bit
> > of PRIDE...
> >
> 
> well, you can certainly overdo it with that last one you know...
> 
> ST

You mean that when I polish and wax the copper before priming with 
clear pre-resist and then a post primer and then resist, then bake 
the coating on prior to confromal coating that I'm doing a little too 
much ?

I always thought that the time it took to polish the solder joints 
was kinda long, espically the parts under the SMT chips.

Seems the only thing that takes longer is when I have to re-work 
resistors so the %rating is always on the right hand side.  SMT are a 
little easier as getting the text lined up does not take as long.

Dave

On Tuesday 11 May 2004 04:26 pm, Dave Mucha wrote:
> > >  It is NOT difficult for a "home worker" to do, either!  Perhaps
> > > needs a bit of PRIDE...

> > well, you can certainly overdo it with that last one you know...
> >
> > ST

> You mean that when I polish and wax the copper before priming with
> clear pre-resist and then a post primer and then resist, then bake
> the coating on prior to confromal coating that I'm doing a little too
> much ?
>
> I always thought that the time it took to polish the solder joints
> was kinda long, espically the parts under the SMT chips.

Hey,  you left out the post-soldering machining of those joints...		:-)

> Seems the only thing that takes longer is when I have to re-work
> resistors so the %rating is always on the right hand side.  SMT are a
> little easier as getting the text lined up does not take as long.

It'd help if they used the same size markings,  too.

Strange question, i know..

any ideas how to chemically blacken the copper on a pcb (copper only, not 
epoxy).

For optical purposes, not electric. should be even colored.

must leave, thanks

ST

On Wed, 12 May 2004 11:04:54 +0200, Stefan Trethan <stefan_trethan@...> 
wrote:

> Strange question, i know..
>
> any ideas how to chemically blacken the copper on a pcb (copper only, not
> epoxy).
>

found something:

<http://www.cpachem.com/en/madchem/06.htm>

Have no sodium thiosulfate at hand, but did read somewhere else
it might work with sulphur, have enough sulphur so i will try....

suggestions welcome.

(It could be used for heatsinks etc...)

ST

--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
<stefan_trethan@g...> wrote:
> Strange question, i know..
> 
> any ideas how to chemically blacken the copper on a pcb (copper
only, not 
> epoxy).
> 
> For optical purposes, not electric. should be even colored.

I found something at an art store a few years ago called "Liver of
Sulphur" which I used to blacken copper for antiquing purposes.

No idea what was in it, or where I have the bottle now to check. Google.

Steve

> I found something at an art store a few years ago called "Liver of
> Sulphur" which I used to blacken copper for antiquing purposes.
>
> No idea what was in it, or where I have the bottle now to check. Google.
>
> Steve
>
>

Read about that too, same lack of idea what it is here.

ST

In article <opr7wfrpnoooawdc@...>,
   Stefan Trethan <stefan_trethan@...> wrote:
> > I found something at an art store a few years ago called "Liver of
> > Sulphur" which I used to blacken copper for antiquing purposes.

Pottasium Sulphide

Stuart.

On Wed, 12 May 2004 22:37:23 +0100, lists 
<stuart.winsor.lists@...> wrote:

> In article <opr7wfrpnoooawdc@...>,
>    Stefan Trethan <stefan_trethan@...> wrote:
>> > I found something at an art store a few years ago called "Liver of
>> > Sulphur" which I used to blacken copper for antiquing purposes.
>
> Pottasium Sulphide
>
> Stuart.
>

thanks, don't have this one either..

guess i must buy something..

ST

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

From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, May 12, 2004 10:04 AM
Subject: [Homebrew_PCBs] Blackening copper


> Strange question, i know..
>
> any ideas how to chemically blacken the copper on a pcb (copper only, not
> epoxy).
>
> For optical purposes, not electric. should be even colored.

http://www.brushplate.com/brush%20plating%20chemicals.htm

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

Leon Heller, G1HSM
http://www.geocities.com/leon_heller

----- Original Message ----- 
From: "Stefan Trethan" <stefan_trethan@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, May 12, 2004 6:06 PM
Subject: Re: [Homebrew_PCBs] Blackening copper


> On Wed, 12 May 2004 11:04:54 +0200, Stefan Trethan <stefan_trethan@...>
> wrote:
>
> > Strange question, i know..
> >
> > any ideas how to chemically blacken the copper on a pcb (copper only,
not
> > epoxy).
> >
>
> found something:
>
> <http://www.cpachem.com/en/madchem/06.htm>
>
> Have no sodium thiosulfate at hand, but did read somewhere else
> it might work with sulphur, have enough sulphur so i will try....

Sodium thiosulphate (hyposulphate) is the old 'hypo' that used to be used as
a photographic developer.

Leon

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

From: "Steve" <alienrelics@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Wednesday, May 12, 2004 7:12 PM
Subject: [Homebrew_PCBs] Re: Blackening copper


> --- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> <stefan_trethan@g...> wrote:
> > Strange question, i know..
> >
> > any ideas how to chemically blacken the copper on a pcb (copper
> only, not
> > epoxy).
> >
> > For optical purposes, not electric. should be even colored.
>
> I found something at an art store a few years ago called "Liver of
> Sulphur" which I used to blacken copper for antiquing purposes.
>
> No idea what was in it, or where I have the bottle now to check. Google.

As someone else said, it's potassium sulphide. IIRC it's made by heating
potassium metal and sulphur. This could be dangerous, BTW.

Leon
--
Leon Heller, G1HSM
http://www.geocities.com/leon_heller

Leon Heller wrote:
> ----- Original Message ----- 
> From: "Steve" <alienrelics@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Wednesday, May 12, 2004 7:12 PM
> Subject: [Homebrew_PCBs] Re: Blackening copper
> 
>>--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
>><stefan_trethan@g...> wrote:
>>
>>>Strange question, i know..
>>>
>>>any ideas how to chemically blacken the copper on a pcb (copper
>>
>>only, not
>>
>>>epoxy).
>>>
>>>For optical purposes, not electric. should be even colored.
>>
>>I found something at an art store a few years ago called "Liver of
>>Sulphur" which I used to blacken copper for antiquing purposes.
>>
>>No idea what was in it, or where I have the bottle now to check. Google.
> 
> As someone else said, it's potassium sulphide. IIRC it's made by heating
> potassium metal and sulphur. This could be dangerous, BTW.

Maybe reacting potassium hydroxide with sulphuric acid could give
something.

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

From: "Russell Shaw" <rjshaw@...>
To: <Homebrew_PCBs@yahoogroups.com>
Sent: Saturday, May 15, 2004 8:10 AM
Subject: Re: [Homebrew_PCBs] Re: Blackening copper


> Leon Heller wrote:
> > ----- Original Message ----- 
> > From: "Steve" <alienrelics@...>
> > To: <Homebrew_PCBs@yahoogroups.com>
> > Sent: Wednesday, May 12, 2004 7:12 PM
> > Subject: [Homebrew_PCBs] Re: Blackening copper
> >
> >>--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
> >><stefan_trethan@g...> wrote:
> >>
> >>>Strange question, i know..
> >>>
> >>>any ideas how to chemically blacken the copper on a pcb (copper
> >>
> >>only, not
> >>
> >>>epoxy).
> >>>
> >>>For optical purposes, not electric. should be even colored.
> >>
> >>I found something at an art store a few years ago called "Liver of
> >>Sulphur" which I used to blacken copper for antiquing purposes.
> >>
> >>No idea what was in it, or where I have the bottle now to check. Google.
> >
> > As someone else said, it's potassium sulphide. IIRC it's made by heating
> > potassium metal and sulphur. This could be dangerous, BTW.
>
> Maybe reacting potassium hydroxide with sulphuric acid could give
> something.

That will give potassium sulphate, not the sulphide.

Leon

Leon Heller wrote:
> ----- Original Message ----- 
> From: "Russell Shaw" <rjshaw@...>
> To: <Homebrew_PCBs@yahoogroups.com>
> Sent: Saturday, May 15, 2004 8:10 AM
> Subject: Re: [Homebrew_PCBs] Re: Blackening copper
> 
>>Leon Heller wrote:
>>
>>>----- Original Message ----- 
>>>From: "Steve" <alienrelics@...>
>>>To: <Homebrew_PCBs@yahoogroups.com>
>>>Sent: Wednesday, May 12, 2004 7:12 PM
>>>Subject: [Homebrew_PCBs] Re: Blackening copper
>>>
>>>>--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
>>>><stefan_trethan@g...> wrote:
>>>>
>>>>>Strange question, i know..
>>>>>any ideas how to chemically blacken the copper on a pcb (copper
>>>>only, not epoxy).
>>>>>
>>>>>For optical purposes, not electric. should be even colored.
>>>>
>>>>I found something at an art store a few years ago called "Liver of
>>>>Sulphur" which I used to blacken copper for antiquing purposes.
>>>>
>>>>No idea what was in it, or where I have the bottle now to check. Google.
>>>
>>>As someone else said, it's potassium sulphide. IIRC it's made by heating
>>>potassium metal and sulphur. This could be dangerous, BTW.
>>
>>Maybe reacting potassium hydroxide with sulphuric acid could give
>>something.
> 
> That will give potassium sulphate, not the sulphide.

Thought so. But isn't there a heating/reducing step to turn it
into sulphide?

A reminder from the moderator to please trim the replies.

Thanks,
Steve

Russell Shaw wrote:

> Leon Heller wrote:
> 
>>----- Original Message ----- 
>>From: "Russell Shaw" <rjshaw@...>
>>To: <Homebrew_PCBs@yahoogroups.com>
>>Sent: Saturday, May 15, 2004 8:10 AM
>>Subject: Re: [Homebrew_PCBs] Re: Blackening copper
>>
>>
>>>Leon Heller wrote:
>>>
>>>
>>>>----- Original Message ----- 
>>>>From: "Steve" <alienrelics@...>
>>>>To: <Homebrew_PCBs@yahoogroups.com>
>>>>Sent: Wednesday, May 12, 2004 7:12 PM
>>>>Subject: [Homebrew_PCBs] Re: Blackening copper
>>>>
>>>>
>>>>>--- In Homebrew_PCBs@yahoogroups.com, Stefan Trethan
>>>>><stefan_trethan@g...> wrote:
>>>>>
>>>>>
>>>>>>Strange question, i know..
>>>>>>any ideas how to chemically blacken the copper on a pcb (copper
>>>>>
>>>>>only, not epoxy).
>>>>>
>>>>>>For optical purposes, not electric. should be even colored.
>>>>>
>>>>>I found something at an art store a few years ago called "Liver of
>>>>>Sulphur" which I used to blacken copper for antiquing purposes.
>>>>>
>>>>>No idea what was in it, or where I have the bottle now to check. Google.
>>>>
>>>>As someone else said, it's potassium sulphide. IIRC it's made by heating
>>>>potassium metal and sulphur. This could be dangerous, BTW.
>>>
>>>Maybe reacting potassium hydroxide with sulphuric acid could give
>>>something.
>>
>>That will give potassium sulphate, not the sulphide.
> 
> 
> Thought so. But isn't there a heating/reducing step to turn it
> into sulphide?

I know when you *really* heat salts you will get most stable 
form, which would be potassium oxide.

We seem to be getting an awful lot of 3 page quotes 5 messages deep
with one line of "Thanks, I appreciate it" lately

Please trim. And consider sending thanks off list.

I'm not trying to be a control freak. One big plus of the list is the
archive, but the more quoted unrelated text, the harder it is for
newbies to search the archives.

Steve, the moderator