Homebrew PCBs

Other than using eyelets has anyone made Plated Thru Hole at Home and 
can give some tips?

In a message dated 27-Feb-02 10:42:43 Central Standard Time, 
j_hallows@... writes:


> Other than using eyelets has anyone made Plated Thru Hole at Home and 
> can give some tips?


DITTO!  I have OFTEN needed "onesy-twosey" PCB's with PTH, and have had to 
use "jumper wires", eyelets, or have 'em made by the local PCB house for $450 
each!  Seems plating-through should be within the realm of us ol' 
home-brewers who can make a double-sided board, if we just knew the steps, 
and where to get the chemistry to plate the holes before etching.

You DO know, doncha, that the PTH is done FIRST, then "SOLDER-plating" of the 
desired pattern (including through the holes!), and etch LAST, with chemistry 
that will etch copper, but NOT "solder".

Someone TELL us how!  GOOD topic!


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

At 10:43 PM 2/28/02 -0500, JanRwl@... wrote:
>In a message dated 27-Feb-02 10:42:43 Central Standard Time,
>j_hallows@... writes:
>
>
> > Other than using eyelets has anyone made Plated Thru Hole at Home and
> > can give some tips?

I use 2 methods:

'Track Pins' made by Harwin (UK, I think).  We used to get them from 
Arrow/Bell but I don't know if they still have them.

These are a stick of tapered pins that you push into the hole, then snap 
off.  Nice tight fit into a #66 hole.  Quick, fast, reliable.  Only down 
side is that they are good for vias only - they fill the hole so you can't 
put a component lead through.


Multicore makes a system called Copperset 
<http://www.multicore.com/detail.asp?id=35&cat=Accessories>

This is a little stick of solid solder which has copper and tin 
electroplated over it.  It is then scored at intervals slightly more than 
the average PCB thickness.  You drill the via holes to the correct 
diameter, then insert the stick and snap off the vias one at at time.  You 
then use an impact punch to squash the via - doing so causes the solid 
solder rod to expand the copper / tin coating so as to grip the sides of 
the hole in the PCB.  Solder both sides of the via, then vacuum out the 
solder if you need to put a component lead in.

I have one and use if occasionally - it works well but is actually more 
work than the Harwin Track pins I mentioned earlier.

It works best if you use it before the board is populated - place the board 
on a smooth steel surface, insert the feed-through pins, then set them with 
the impact punch.

dwayne


Dwayne Reid   <dwayner@...>
Trinity Electronics Systems Ltd    Edmonton, AB, CANADA
(780) 489-3199 voice          (780) 487-6397 fax

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--- In Homebrew_PCBs@y..., JanRwl@A... wrote:
> each!  Seems plating-through should be within the realm of us ol' 
> home-brewers who can make a double-sided board, if we just knew the 
steps, 
> and where to get the chemistry to plate the holes before etching.
> 

Could not agree more. I know the thoery but the practice it's a whole 
different ball park.


> You DO know, doncha, that the PTH is done FIRST, then "SOLDER-
plating" of the 
> desired pattern (including through the holes!), and etch LAST, 
> with chemistry that will etch copper, but NOT "solder".
> 

Took me sometime to figure this one out. But it's not solder but 
tinned. And the process is called pattern plating.

As a homebrewer it is too expensive for me to send boards out to 
make. If I could only find out a simple way to make plated thru holes 
at home without killing myself. And eyelets and baluns are too time 
consuming.

--- In Homebrew_PCBs@y..., "j_hallows" <j_hallows@h...> wrote:
> --- In Homebrew_PCBs@y..., JanRwl@A... wrote:
> > each!  Seems plating-through should be within the realm of us ol' 
> > home-brewers who can make a double-sided board, if we just knew 
the 
> steps, 
> > and where to get the chemistry to plate the holes before etching.
> > 
> 
> Could not agree more. I know the thoery but the practice it's a 
whole 
> different ball park.
> 
> 
> > You DO know, doncha, that the PTH is done FIRST, then "SOLDER-
> plating" of the 
> > desired pattern (including through the holes!), and etch LAST, 
> > with chemistry that will etch copper, but NOT "solder".
> > 
> 
> Took me sometime to figure this one out. But it's not solder but 
> tinned. And the process is called pattern plating.
> 
> As a homebrewer it is too expensive for me to send boards out to 
> make. If I could only find out a simple way to make plated thru 
holes 
> at home without killing myself. And eyelets and baluns are too time 
> consuming.


Hi there, 

I just discovered this yahoo groups forum on making PCBs at 
home. Its good to see people out there making boards 
themselves. When I saw the post on trying to do PTH at home I 
though this could be something I might able to answer.

Making plated boards involved many more processes than a 
simple 'print and etch' method. I'm sure you know that first the 
holes must be made conductive in order to electroplate with 
copper. This is one of the major challenges, and the industry may 
use one of several techniques. I will not go into the details 
because much of this information in already explained on the 
web. An excellent information source is;

http://www.epa.gov/dfe/pubs/pwb/tech_rep/usecluster/pr_toc.htm

PTHs are possible to do at home but you should be aware that it 
involves many chemical stages. Although these chemicals are not 
necessary highly toxic they can be a difficult process to control 
and get working properly. So unless you find chemistry fun and 
don't mind getting your hands wet then I its a complete waste of 
time and money trying to implement a PTH workshop at home. I 
have setup the necessary plating and etching tanks to make a tin 
finish pattern plated board and had taken me almost two years. 
The holes are made conductive using a processes similar to 
MacDermid's BLACKHOLE processes where by a conductive carbon 
black layer deposited inside the holes prior to electroplating. If 
you have any questions then feel free to ask.

Adam

> PTHs are possible to do at home but you should be aware that it 
> involves many chemical stages. Although these chemicals are not 
> necessary highly toxic they can be a difficult process to control 
> and get working properly. So unless you find chemistry fun and 
> don't mind getting your hands wet then I its a complete waste of 
> time and money trying to implement a PTH workshop at home. I 
> have setup the necessary plating and etching tanks to make a tin 
> finish pattern plated board and had taken me almost two years. 
> The holes are made conductive using a processes similar to 
> MacDermid's BLACKHOLE processes where by a conductive carbon 
> black layer deposited inside the holes prior to electroplating. If 
> you have any questions then feel free to ask.
> 

Hey Adam maybe you should write a produre of your method of making 
PTH. I would love to know the costs involved and chemistry. I am not 
familar with the BLACKHOLE method. The hardest part is making the 
holes conductive. I know the squeezee method were you squeeze 
conductive ink into the holes. But the ink is very expensive. Also 
the Gallum method but Gallum is hard to find. Is the BLACKHOLE the 
same.

Thanks.

--
John Hallows

The BLACKHOLE processes is fast, cheaper and safer to run than conventional
electroless copper. This is expected since its aim is to replace the
electroless copper line in the PCB fabrication plant. The low toxicity is the
reason I choose to develop a carbon black processes myself at home. However
the chemistry of BLACKHOLE is a trade secret and your not going to replicate
the same results at home. BLACKHOLE SP is the latest process from MacDermid
and performs many times better than the process explained below. Of course
the hobbyist doesn't need the reliability of a multimillion dollar plant
producing a hundreds of panels a day. Its taken me about 6 months of fiddling
around with carbon black dispersions, conditioning solutions and circuit
board material to get a working process suitable for home use. Basically my
process can be written down as follows;

1) drill PCB
2) clean copper surface with week solution of detergent/NaOH and 600 emery
paper.
3) rinse well with tap water
4) immerse in a "hole wall conditioner" 1 min
5) rinse well with with tap water
6) immerse in "carbon dispersion" 1 min
7) sponge off excess dispersion with sponge, so all holes are fully empty.
8) hot air dry
9) repeat steps 4 to 8
10) immerse in "activator" for 1 minute
11) rinse well with with tap water
12) microetch in a conventional non-chloride etching solution
13) spray rinse with with tap water to remove all traces of carbon on copper
surface.
14) air dry  (optional)


Bath compositions/conditions;

hole wall conditioner:
    5 to 10 g/l gelatine
    0.04 to 0.06 g/l CuSO4.5H20 (as a biocide)
    temperature between 26\ufffdC and 32\ufffdC
    agitation: unnecessary


carbon dispersion:
    2 to 4% (w/w) of non-ionic surfactant based
           conductive carbon black dispersion paste*
    6 to 10 g/l  acetic acid
    room temperature
    agitation: unnecessary


activator:
        1 g/l of dye D&C Green No.5 ,  C.I 61570.
        room temperature
        agitation: not known

non-chloride etchant:
        100 to 200 g/l ammonium persulfate
     or
        1% hydrogen peroxide
        10% sulfuric acid.
        both baths may be used at room temperature.


* The carbon black dispersion paste is FLEXOBRITE BLACK 258/86 manufactured
by Degussa Coatings & Colorants.

You will have to phone around and get a 500g sample for aqueous based
non-ionic surfactant conductive carbon black dispersion. Many of the colorant
manufactures will have these. 500g will last you forever. There is still a
whole range of information I left out, either because I haven't worked it out
yet or I missed it. The D&C Green No5 is available from food, drug & cosmetic
dye suppliers, either as a sample or in small volume (1 kg). Good luck

Adam





j_hallows wrote:

> > PTHs are possible to do at home but you should be aware that it
> > involves many chemical stages. Although these chemicals are not
> > necessary highly toxic they can be a difficult process to control
> > and get working properly. So unless you find chemistry fun and
> > don't mind getting your hands wet then I its a complete waste of
> > time and money trying to implement a PTH workshop at home. I
> > have setup the necessary plating and etching tanks to make a tin
> > finish pattern plated board and had taken me almost two years.
> > The holes are made conductive using a processes similar to
> > MacDermid's BLACKHOLE processes where by a conductive carbon
> > black layer deposited inside the holes prior to electroplating. If
> > you have any questions then feel free to ask.
> >
>
> Hey Adam maybe you should write a produre of your method of making
> PTH. I would love to know the costs involved and chemistry. I am not
> familar with the BLACKHOLE method. The hardest part is making the
> holes conductive. I know the squeezee method were you squeeze
> conductive ink into the holes. But the ink is very expensive. Also
> the Gallum method but Gallum is hard to find. Is the BLACKHOLE the
> same.
>
> Thanks.
>
> --
> John Hallows
>
>
> 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/

Why not use Circuit Works conductive epoxy?

No doubt it has a use for repairing things that need to be conductive.
I can't see squeezing epoxy into 500-1500 0.032" holes.
Another thing it would not allow through hole connections where
components like sockets need to be soldered in place. The chance of a
short due to smearing the epoxy during application makes me think it's
never going to be practical as a through hole connection.
hansw


caveteursus wrote:

>  Why not use Circuit Works conductive epoxy?
>
>
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>
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[Non-text portions of this message have been removed]

This sounds good. I assume that this is just for hole activation and 
standard electroplating is done next to build up the holes. What is 
the success rate at home? And estimated costs? I don't want to dive 
into something that would be so hard to replicate. Thanks for the 
Info Adam. 


--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
> The BLACKHOLE processes is fast, cheaper and safer to run than 
conventional
> electroless copper. This is expected since its aim is to replace the
> electroless copper line in the PCB fabrication plant. The low 
toxicity is the
> reason I choose to develop a carbon black processes myself at home. 
However
> the chemistry of BLACKHOLE is a trade secret and your not going to 
replicate
> the same results at home. BLACKHOLE SP is the latest process from 
MacDermid
> and performs many times better than the process explained below. Of 
course
> the hobbyist doesn't need the reliability of a multimillion dollar 
plant
> producing a hundreds of panels a day. Its taken me about 6 months 
of fiddling
> around with carbon black dispersions, conditioning solutions and 
circuit
> board material to get a working process suitable for home use. 
Basically my
> process can be written down as follows;
> 
> 1) drill PCB
> 2) clean copper surface with week solution of detergent/NaOH and 
600 emery
> paper.
> 3) rinse well with tap water
> 4) immerse in a "hole wall conditioner" 1 min
> 5) rinse well with with tap water
> 6) immerse in "carbon dispersion" 1 min
> 7) sponge off excess dispersion with sponge, so all holes are fully 
empty.
> 8) hot air dry
> 9) repeat steps 4 to 8
> 10) immerse in "activator" for 1 minute
> 11) rinse well with with tap water
> 12) microetch in a conventional non-chloride etching solution
> 13) spray rinse with with tap water to remove all traces of carbon 
on copper
> surface.
> 14) air dry  (optional)
> 
> 
> Bath compositions/conditions;
> 
> hole wall conditioner:
>     5 to 10 g/l gelatine
>     0.04 to 0.06 g/l CuSO4.5H20 (as a biocide)
>     temperature between 26°C and 32°C
>     agitation: unnecessary
> 
> 
> carbon dispersion:
>     2 to 4% (w/w) of non-ionic surfactant based
>            conductive carbon black dispersion paste*
>     6 to 10 g/l  acetic acid
>     room temperature
>     agitation: unnecessary
> 
> 
> activator:
>         1 g/l of dye D&C Green No.5 ,  C.I 61570.
>         room temperature
>         agitation: not known
> 
> non-chloride etchant:
>         100 to 200 g/l ammonium persulfate
>      or
>         1% hydrogen peroxide
>         10% sulfuric acid.
>         both baths may be used at room temperature.
> 
> 
> * The carbon black dispersion paste is FLEXOBRITE BLACK 258/86 
manufactured
> by Degussa Coatings & Colorants.
> 
> You will have to phone around and get a 500g sample for aqueous 
based
> non-ionic surfactant conductive carbon black dispersion. Many of 
the colorant
> manufactures will have these. 500g will last you forever. There is 
still a
> whole range of information I left out, either because I haven't 
worked it out
> yet or I missed it. The D&C Green No5 is available from food, drug 
& cosmetic
> dye suppliers, either as a sample or in small volume (1 kg). Good 
luck
> 
> Adam

--- In Homebrew_PCBs@y..., "caveteursus" <j.walton@a...> wrote:
> Why not use Circuit Works conductive epoxy?

I think this product is just for reworking/repairing traces. Also 
imagine if I had a board with 10000 holes. Do you think I want to 
spend me time coating each hole.

--
John Hallows

The cost is not the problem since the carbon dispersion should be available
free from one of the large colorant producers. The dye is similarly
available. I got 20 kg of dispersion paste for $130 AU. This is enough to
make about 1000 liters of solution. I've used about 100 grams so far. The
cost will be in building or setting up your chemical tanks. Plating copper is
easy but trying to plate uniform smooth copper on to your PCB takes a lot
more effort. I would say the carbon black process is simple relative to
copper plating. In other words, if you can get successful copper plating then
I'm sure the carbon black process will be easy for you. The success rate for
plating holes is just about perfect, but it has taken me a long time to get
at this stage. The guide I described is a good start. The only concern I have
is that a different carbon black dispersion concentrate may give different
results.


Adam

j_hallows wrote:

> This sounds good. I assume that this is just for hole activation and
> standard electroplating is done next to build up the holes. What is
> the success rate at home? And estimated costs? I don't want to dive
> into something that would be so hard to replicate. Thanks for the
> Info Adam.
>
> --- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
> > The BLACKHOLE processes is fast, cheaper and safer to run than
> conventional
> > electroless copper. This is expected since its aim is to replace the
> > electroless copper line in the PCB fabrication plant. The low
> toxicity is the
> > reason I choose to develop a carbon black processes myself at home.
> However
> > the chemistry of BLACKHOLE is a trade secret and your not going to
> replicate
> > the same results at home. BLACKHOLE SP is the latest process from
> MacDermid
> > and performs many times better than the process explained below. Of
> course
> > the hobbyist doesn't need the reliability of a multimillion dollar
> plant
> > producing a hundreds of panels a day. Its taken me about 6 months
> of fiddling
> > around with carbon black dispersions, conditioning solutions and
> circuit
> > board material to get a working process suitable for home use.
> Basically my
> > process can be written down as follows;
> >
> > 1) drill PCB
> > 2) clean copper surface with week solution of detergent/NaOH and
> 600 emery
> > paper.
> > 3) rinse well with tap water
> > 4) immerse in a "hole wall conditioner" 1 min
> > 5) rinse well with with tap water
> > 6) immerse in "carbon dispersion" 1 min
> > 7) sponge off excess dispersion with sponge, so all holes are fully
> empty.
> > 8) hot air dry
> > 9) repeat steps 4 to 8
> > 10) immerse in "activator" for 1 minute
> > 11) rinse well with with tap water
> > 12) microetch in a conventional non-chloride etching solution
> > 13) spray rinse with with tap water to remove all traces of carbon
> on copper
> > surface.
> > 14) air dry  (optional)
> >
> >
> > Bath compositions/conditions;
> >
> > hole wall conditioner:
> >     5 to 10 g/l gelatine
> >     0.04 to 0.06 g/l CuSO4.5H20 (as a biocide)
> >     temperature between 26\ufffdC and 32\ufffdC
> >     agitation: unnecessary
> >
> >
> > carbon dispersion:
> >     2 to 4% (w/w) of non-ionic surfactant based
> >            conductive carbon black dispersion paste*
> >     6 to 10 g/l  acetic acid
> >     room temperature
> >     agitation: unnecessary
> >
> >
> > activator:
> >         1 g/l of dye D&C Green No.5 ,  C.I 61570.
> >         room temperature
> >         agitation: not known
> >
> > non-chloride etchant:
> >         100 to 200 g/l ammonium persulfate
> >      or
> >         1% hydrogen peroxide
> >         10% sulfuric acid.
> >         both baths may be used at room temperature.
> >
> >
> > * The carbon black dispersion paste is FLEXOBRITE BLACK 258/86
> manufactured
> > by Degussa Coatings & Colorants.
> >
> > You will have to phone around and get a 500g sample for aqueous
> based
> > non-ionic surfactant conductive carbon black dispersion. Many of
> the colorant
> > manufactures will have these. 500g will last you forever. There is
> still a
> > whole range of information I left out, either because I haven't
> worked it out
> > yet or I missed it. The D&C Green No5 is available from food, drug
> & cosmetic
> > dye suppliers, either as a sample or in small volume (1 kg). Good
> luck
> >
> > Adam
>
>
> 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/

If I had a design with hundreds of boards, or multilayer boards, or 
even tens of through-holes on 4 or 5 boards, I think that I could 
find better uses of my time than etching them "homebrew" style.  
Homebrew is great for PROTO's and One-off's, where you would like 
something in a couple of hours, but the personal economics quickly 
get swamped.

In a message dated 04-Mar-02 08:15:05 Central Standard Time, 
j.walton@... writes:


> Homebrew is great for PROTO's and One-off's, where you would like 
> something in a couple of hours, but the personal economics quickly 
> get swamped.  


Exactly!  The only things that would make PTH at home "worth it" would be any 
one or combination of the following:

1.  The personal "need" to prove "I can DO that!";
2.   A lack of a professional PC-house within 50 miles, that will do  PTH for 
you, essentially "while you wait";
3.  A need to make PTH boards for a top-secret national-defence project that 
must be completed TONIGHT;



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

At 12:05 PM 4/03/2002 EST, you wrote:
>In a message dated 04-Mar-02 08:15:05 Central Standard Time, 
>j.walton@... writes:
>
>
>> Homebrew is great for PROTO's and One-off's, where you would like 
>> something in a couple of hours, but the personal economics quickly 
>> get swamped.  
>
>
>Exactly!  The only things that would make PTH at home "worth it" would be
any 
>one or combination of the following:
>
>1.  The personal "need" to prove "I can DO that!";
>2.   A lack of a professional PC-house within 50 miles, that will do  PTH
for 
>you, essentially "while you wait";
>3.  A need to make PTH boards for a top-secret national-defence project that 
>must be completed TONIGHT;
>
>

Yes, it simply not worth doing PTH for a hobby. That's why I am selling the
boards I make.
Admittedly up until now they have all been single sided requests.

--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
> The cost is not the problem since the carbon dispersion should be 
available
> free from one of the large colorant producers. The dye is similarly
> available. I got 20 kg of dispersion paste for $130 AU. This is 
enough to
> make about 1000 liters of solution. I've used about 100 grams so 
far. The
> cost will be in building or setting up your chemical tanks. Plating 
copper is
> easy but trying to plate uniform smooth copper on to your PCB takes 
a lot
> more effort. I would say the carbon black process is simple 
relative to
> copper plating. In other words, if you can get successful copper 
plating then
> I'm sure the carbon black process will be easy for you. The success 
rate for
> plating holes is just about perfect, but it has taken me a long 
time to get
> at this stage. The guide I described is a good start. The only 
concern I have
> is that a different carbon black dispersion concentrate may give 
different
> results.
> 
> 
> Adam
> 

I had a nice long reply to the group, (covering two posts). But it
seems yahoo decided to screw up my message. But the gist was
the cost of producing prototypes at home or sending away. I am not
too concern at plating since I am thinking of buying a prototype
plating machine. I more worried about making the holes conductive.
Your prodeduce looks appealing.

Lates.

--- In Homebrew_PCBs@y..., "caveteursus" <j.walton@a...> wrote:
> If I had a design with hundreds of boards, or multilayer boards, or 
> even tens of through-holes on 4 or 5 boards, I think that I could 
> find better uses of my time than etching them "homebrew" style.  
> Homebrew is great for PROTO's and One-off's, where you would like 
> something in a couple of hours, but the personal economics quickly 
> get swamped.

I have to admit I tradionally prototype using wirewrap method. I find
this faster with debugging. But since everyone is moving to highspeed
devices with more compact densities, (like PGA), I have no choice but
figure a way to easily make multilayer, (or doubly sided) boards at
home. The cost of sending away for boards to be made is a little
costly for me.

You are right about the economics part.

I was considering saving all my pennies and buying a commerical
prototype PCB plating machine. They are around the $1000.00 mark,
(the cost of sending out 20 boards to be made). I can always make my
money back by making prototypes for others at half the cost but this
isn't the main reason. But the main problem is making the holes
conductive in the first place which Adam address. This method seems
the easiest but major draw back is the experimenting with chemicals
to get the right ratio.

This is my first plan. My second plan would be to register in a local
community college PCB manufacturing course and use thier equipment.
$200.00 for the course and 50 prototypes made. ;) Cheaper I think.

I'm afraid it doesn't work like that. Buying a secondhand plating machine
ain't going to make you PCBs. There is long list of processing tanks
required along with an good understanding of the process. If ALL you are
trying to do is save money then your idea of making PTH at home is not
logical. Bath compositions are given to you by the vendors of the plating
additives and chemicals. You can also find much information in books. There
is no need for you to re-invent the wheel.

>I was considering saving all my pennies and buying a commerical
>prototype PCB plating machine. They are around the $1000.00 mark,
>(the cost of sending out 20 boards to be made). I can always make my
>money back by making prototypes for others at half the cost but this
>isn't the main reason. But the main problem is making the holes
>conductive in the first place which Adam address. This method seems
>the easiest but major draw back is the experimenting with chemicals
>to get the right ratio.
>
>This is my first plan. My second plan would be to register in a local
>community college PCB manufacturing course and use thier equipment.
>$200.00 for the course and 50 prototypes made. ;) Cheaper I think.
>
>
>
>
>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/ 
>
>

I've been interested  the subject of plated through holes for a long
time, however the cost of making 2 sided PCB's is so low it is not worth
the effort to start the mess with chemicals and plating tanks, not least
getting rid of old chemicals can become a problem.

Example: Two boards of Two Sided board with through plated holes, LPI
mask and silk screen, any size upto 64 square inches. $33.00 (thirty
three US dollars) per board total cost $66.00 no tooling charges, there
are a few limitation on drill sizes the smallest is 20 mil. Plus
freight... Five days turnaround.
Hans Wedemeyer

j_hallows wrote:

>
> I had a nice long reply to the group, (covering two posts). But it
> seems yahoo decided to screw up my message. But the gist was
> the cost of producing prototypes at home or sending away. I am not
> too concern at plating since I am thinking of buying a prototype
> plating machine. I more worried about making the holes conductive.
> Your prodeduce looks appealing.
>
> Lates.
>
>
>
>
>
>                    Yahoo! Groups Sponsor
                        ADVERTISEMENT


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At 04:11 AM 6/03/2002 -0000, you wrote:
>--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
>> The cost is not the problem since the carbon dispersion should be 
>available
>> free from one of the large colorant producers. The dye is similarly
>> available. I got 20 kg of dispersion paste for $130 AU. This is 
>enough to
>> make about 1000 liters of solution. I've used about 100 grams so 
>far. The
>> cost will be in building or setting up your chemical tanks. Plating 
>copper is
>> easy but trying to plate uniform smooth copper on to your PCB takes 
>a lot
>> more effort. I would say the carbon black process is simple 
>relative to
>> copper plating. In other words, if you can get successful copper 
>plating then
>> I'm sure the carbon black process will be easy for you. The success 
>rate for
>> plating holes is just about perfect, but it has taken me a long 
>time to get
>> at this stage. The guide I described is a good start. The only 
>concern I have
>> is that a different carbon black dispersion concentrate may give 
>different
>> results.
>> 
>> 
>> Adam
>> 
>
>I had a nice long reply to the group, (covering two posts). But it
>seems yahoo decided to screw up my message. But the gist was
>the cost of producing prototypes at home or sending away. I am not
>too concern at plating since I am thinking of buying a prototype
>plating machine. I more worried about making the holes conductive.
>Your prodeduce looks appealing.
>
>Lates.
>
>

First you should worry about how your going to etch. If you decide on
pattern plate then you have choice of tin or tin/lead metal resist. If you
choose tin then you must use alkaline ammonia etch. If you choose tin/lead
then can use sulfuric/peroxide, ammonium persulfate etch, or ammonia etch.
However, I would be wary on having toxic lead plating solutions laying
around. For the ammonia etch it can be chloride or sulfate based. If
chloride based then you have major waste problems because the copper cannot
be recovered easily (at least what I know) and you will need to treat then
dump your solution ($$$). If you use sulfate based alkaline ammonia then
the etchant can be electrolytically regenerated although the etching rate
is much slower than chloride. 

PCB fabrication may look simple on a flow chart but when it comes to
actually making it work its a whole different story.

Adam

--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
> I'm afraid it doesn't work like that. Buying a secondhand plating 
machine
> ain't going to make you PCBs. 

I didn't mean second hand. I have been looking at the Prototype 
plating machines. Like QuickPLATE. But they all seem to use the 
process of squeezing conductive ink into the hole manually. The INK 
in itself is expensive.

BTW: In your process the board is completely coated then plated 
correct? So the board must have a thinner layer of copper to work 
with in the first place or the thickness would be uneven correct?

Lates.

--
John Hallows

> First you should worry about how your going to etch. 

You read my mine this was my next question.


> If you decide on
> pattern plate then you have choice of tin or tin/lead metal resist. 
If you
> choose tin then you must use alkaline ammonia etch. If you choose 
tin/lead
> then can use sulfuric/peroxide, ammonium persulfate etch, or 
ammonia etch.

Is this the same stuff called Liquid Tin by MG Chemicals and a 
similar prodouct by Datak? Or would these get disolved by the etching 
solution?

> However, I would be wary on having toxic lead plating solutions 
laying
> around. For the ammonia etch it can be chloride or sulfate based. If
> chloride based then you have major waste problems because the 
copper cannot
> be recovered easily (at least what I know) and you will need to 
treat then
> dump your solution ($$$).

This is like ferric chloride?

 If you use sulfate based alkaline ammonia then
> the etchant can be electrolytically regenerated although the 
etching rate
> is much slower than chloride. 
> 
> PCB fabrication may look simple on a flow chart but when it comes to
> actually making it work its a whole different story.
> 

Please excuse my ignorance. I have a lot zeal and a lot to learn.

At 06:32 AM 7/03/2002 -0000, you wrote:
>--- In Homebrew_PCBs@y..., Adam Seychell <adam_seychell@y...> wrote:
>> I'm afraid it doesn't work like that. Buying a secondhand plating 
>machine
>> ain't going to make you PCBs. 
>
>I didn't mean second hand. I have been looking at the Prototype 
>plating machines. Like QuickPLATE. But they all seem to use the 
>process of squeezing conductive ink into the hole manually. The INK 
>in itself is expensive.
>
>BTW: In your process the board is completely coated then plated 
>correct? So the board must have a thinner layer of copper to work 
>with in the first place or the thickness would be uneven correct?
>
>Lates.
>
>--
>John Hallows
>

By starting off with blank copper cladded board you mean ? then yes. 
The process is called "pattern plate" which I think is the most common
method of making through hole boards, both double sided and multilayer. The
other widely used method is "panel plate". This requires better setup with
photoresist and it must "tent" the hole walls to stop etchant from removing
copper inside the holes.
The carbon black though hole method is not suitable for making large
surfaces conductive. The holes are of relatively short dimension so the
contacts made to the carbon (i.e. at the hole ends where it meets up with
copper foil) can propagate copper through the hole wall during the first 1
to 2 minutes of the copper electroplating process.


Here is a good link describing the steps on manufacturing a multilayer
board (pattern plating).

http://www.pha.jhu.edu/~akeeney/PWB/


some more PCB info can be had at;

http://www.epa.gov/dfe/pubs/pwb/tech_rep/usecluster/pr_toc.htm

Ok, copper etchants come in many different flavors. The ammonia alkaline are
type the most commonly used for tin or tin/lead metal resists (i.e. pattern
plating). The tin forms near perfect resistance (3 um thickness) to the
ammonia type etchants, especially the sulfate based. I recommend visiting
your local university library and getting hold of a book called "Coombs'
Printed Circuits Handbook". It has many of the basics of PCB fabrication that
can start you off.

Here is the alkaline ammonia sulfate etchant I use. It is suitable for room
temp operation; Note: the high alkalinity makes it not suitable for use with
photoresists.

CuSO4.5H20   -              150 to 190 g/l  (optimum 175 g/l)
25%(wt) aqua ammonia - 70% (vol.)
98% sulfuric acid  -         3.0% to 4.0% (vol.)

pH should be between 10 and 11, adjust with aqua ammonia additions.
Tank must be sealed virtually air tight when not in use. Otherwise NH3 will
evaporate over time and pH drops significantly. regeneration is done with
stainless steel anodes in stagnate solution at current density between 3 and
5 A/dm2. Etch times at 25\ufffdC using air bubble agitation is 20 to 25 minutes
for 35 um copper foil. Only one place in the world I know of markets this
type of etchant, and that is the German company Elo-Chem. You won't see it
documented in many places.

http://www.elo-chem.de/html/english.html

No one uses electroless tin unless they have to. The tin is plated on all the
tracks directly after copper plating. Electrolytic tin plating works much
faster, cheaper, safer, more reliable, lower maintenance and more predictable
than electroless tin. The bath I use is the acid stannous sulfate type (looks
like banana flavored milk drink). See your friendly plating supplier for
necessary brighteners and chemicals.




j_hallows wrote:

> > First you should worry about how your going to etch.
>
> You read my mine this was my next question.
>
> > If you decide on
> > pattern plate then you have choice of tin or tin/lead metal resist.
> If you
> > choose tin then you must use alkaline ammonia etch. If you choose
> tin/lead
> > then can use sulfuric/peroxide, ammonium persulfate etch, or
> ammonia etch.
>
> Is this the same stuff called Liquid Tin by MG Chemicals and a
> similar prodouct by Datak? Or would these get disolved by the etching
> solution?
>
> > However, I would be wary on having toxic lead plating solutions
> laying
> > around. For the ammonia etch it can be chloride or sulfate based. If
> > chloride based then you have major waste problems because the
> copper cannot
> > be recovered easily (at least what I know) and you will need to
> treat then
> > dump your solution ($$$).
>
> This is like ferric chloride?
>
>  If you use sulfate based alkaline ammonia then
> > the etchant can be electrolytically regenerated although the
> etching rate
> > is much slower than chloride.
> >
> > PCB fabrication may look simple on a flow chart but when it comes to
> > actually making it work its a whole different story.
> >
>
> Please excuse my ignorance. I have a lot zeal and a lot to learn.
>
>
> 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/

Yep, already had those in the Bookmarks section. I might have
gotten them from Adam originally.

Steve Greenfield

--- Adam Seychell <adam_seychell@...> wrote:

> Here is a good link describing the steps on manufacturing a
> multilayer
> board (pattern plating).
> 
> http://www.pha.jhu.edu/~akeeney/PWB/
> 
> some more PCB info can be had at;
> 
> http://www.epa.gov/dfe/pubs/pwb/tech_rep/usecluster/pr_toc.htm


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>Example: Two boards of Two Sided board with through plated holes, LPI
>mask and silk screen, any size upto 64 square inches. $33.00 (thirty
>three US dollars) per board total cost $66.00 no tooling charges, there
>are a few limitation on drill sizes the smallest is 20 mil. Plus
>freight... Five days turnaround.
>Hans Wedemeyer

	It seems incredible, but in Brazil, boards are A LOT CHEAPER than USA. The same board you are talking about, costs around $20 for 10 boards ($20 all the 10 boards, not $20 each). Incredible. But true. 


---8<---Corte aqui---8<----

Alexandre Souza
taito@...
http://planeta.terra.com.br/lazer/pinball/

---8<---Corte aqui---8<----