Homebrew_PCBs

Hi
Do any of you people here know of a quick and cheap way to tin copper PCB tracks before populating the board?
With all the modern chemicals around these days theirs bound to something out there
In the past have used the manufactured stuff which you just put in a bath for a while and job done but its to expensive.

Thanks in advance

Dave

On 15/08/13 18:00, David wrote:

>
> Hi
> Do any of you people here know of a quick and cheap way to tin copper
> PCB tracks before populating the board?
> With all the modern chemicals around these days theirs bound to
> something out there
> In the past have used the manufactured stuff which you just put in a
> bath for a while and job done but its to expensive.
>

There is basically that (tinnit, liquidtin), and a product called "Cool
Amp" http://www.cool-amp.com/cool_amp.html

I've never found any reasonable "home brew" recipe for such a product.




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

Hi
Thanks for the quick response
See what I mean by price, if you start using that then just as well buy ready made PCBs and forget DIY
Lets see if theirs any other ideas out there


________________________________
From: James <bitsyboffin@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, 15 August 2013, 7:04
Subject: Re: [Homebrew_PCBs] silver coating

On 15/08/13 18:00, David wrote:
>
> Hi
> Do any of you people here know of a quick and cheap way to tin copper
> PCB tracks before populating the board?
> With all the modern chemicals around these days theirs bound to
> something out there
> In the past have used the manufactured stuff which you just put in a
> bath for a while and job done but its to expensive.
>
There is basically that (tinnit, liquidtin), and a product called "Cool
Amp" http://www.cool-amp.com/cool_amp.html

I've never found any reasonable "home brew" recipe for such a product.

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




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

I've seen recipes for tinnit, they all contained thiourea.
Nasty stuff so I didn't follow up on it.

The other option is hot tinning, you can use either solder paste or some
kind of immersion or roll transfer process.

ST

On Thu, Aug 15, 2013 at 8:14 AM, David Pickering <satdaveuk@...>wrote:

> Hi
> Thanks for the quick response
> See what I mean by price, if you start using that then just as well buy
> ready made PCBs and forget DIY
> Lets see if theirs any other ideas out there
>
>
> ________________________________
> From: James <bitsyboffin@...>
> To: Homebrew_PCBs@yahoogroups.com
> Sent: Thursday, 15 August 2013, 7:04
> Subject: Re: [Homebrew_PCBs] silver coating
>
>
>
>
> On 15/08/13 18:00, David wrote:
> >
> > Hi
> > Do any of you people here know of a quick and cheap way to tin copper
> > PCB tracks before populating the board?
> > With all the modern chemicals around these days theirs bound to
> > something out there
> > In the past have used the manufactured stuff which you just put in a
> > bath for a while and job done but its to expensive.
> >
> There is basically that (tinnit, liquidtin), and a product called "Cool
> Amp" http://www.cool-amp.com/cool_amp.html
>
> I've never found any reasonable "home brew" recipe for such a product.
>
> [Non-text portions of this message have been removed]
>
>
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>


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

Tinnit is available on Amazon of all places. They seem to be selling a lot
of hobbyist electronics stuff recently. $6.90 + $5.15 shipping. That's
enough to plate 200 square inches, if I recall correctly.

I've used it a couple times, works OK if you follow the instructions
carefully. The copper really has to be completely clean.

The powder lasts forever if you don't mix it up. I mixed up half of each
package and used it. About 13 years later, the solution didn't work, but I
mixed up a new batch from the remaining powder, and it worked fine.

On Thu, Aug 15, 2013 at 12:34 AM, Stefan Trethan <stefan_trethan@...>wrote:

> I've seen recipes for tinnit, they all contained thiourea.
> Nasty stuff so I didn't follow up on it.
>
> The other option is hot tinning, you can use either solder paste or some
> kind of immersion or roll transfer process.
>
> ST
>
>
> On Thu, Aug 15, 2013 at 8:14 AM, David Pickering <satdaveuk@...
> >wrote:
>
> > Hi
> > Thanks for the quick response
> > See what I mean by price, if you start using that then just as well buy
> > ready made PCBs and forget DIY
> > Lets see if theirs any other ideas out there
> >
> >
> > ________________________________
> > From: James <bitsyboffin@...>
> > To: Homebrew_PCBs@yahoogroups.com
> > Sent: Thursday, 15 August 2013, 7:04
> > Subject: Re: [Homebrew_PCBs] silver coating
> >
> >
> >
> >
> > On 15/08/13 18:00, David wrote:
> > >
> > > Hi
> > > Do any of you people here know of a quick and cheap way to tin copper
> > > PCB tracks before populating the board?
> > > With all the modern chemicals around these days theirs bound to
> > > something out there
> > > In the past have used the manufactured stuff which you just put in a
> > > bath for a while and job done but its to expensive.
> > >
> > There is basically that (tinnit, liquidtin), and a product called "Cool
> > Amp" http://www.cool-amp.com/cool_amp.html
> >
> > I've never found any reasonable "home brew" recipe for such a product.
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> >
> > [Non-text portions of this message have been removed]
> >
> >
> >
> > ------------------------------------
> >
> > Be sure to visit the group home and check for new Links, Files, and
> Photos:
> > http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
> >
> >
> >
> >
>
>
> [Non-text portions of this message have been removed]
>
>
>
> ------------------------------------
>
> Be sure to visit the group home and check for new Links, Files, and Photos:
> http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links
>
>
>
>


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

Amazon and Mouser also have MG chemicals 421 Liquid Tin.

It solders fine for me. It is hazardous.

http://www.amazon.com/MG-Chemicals-421-Liquid-Bottle/dp/B008UH3V1K/ref=sr_1_2?ie=UTF8&qid=1376549579&sr=8-2&keywords=tinnit

http://www.mouser.com/Search/ProductDetail.aspx?R=421-125MLvirtualkey59020000virtualkey590-421-125ML

http://www.mouser.com/ds/2/265/421-16426.pdf

http://www.mgchemicals.com/downloads/msds/english/421-liquid.pdf

--Rick

On 8/15/2013 1:00 AM, David wrote:
>
> Hi
> Do any of you people here know of a quick and cheap way to tin copper
> PCB tracks before populating the board?
> With all the modern chemicals around these days theirs bound to
> something out there
> In the past have used the manufactured stuff which you just put in a
> bath for a while and job done but its to expensive.
>
> Thanks in advance
>
> Dave
>
>



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

I have had this bookmarked for years now, but have never got around to
trying it:-
http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=pt-BR&tl=en&u=http://www.py2bbs.qsl.br/banho_estanho.php&usg=ALkJrhj7fJXRaLTdNTmhinb2qUHkMr7fqg

It describes tin plating before etching and seems quite simple.

The site is in portugese, but google translate seems to do a fair job.
Anyone want to give it a go?

On Thu, Aug 15, 2013 at 8:00 AM, David <satdaveuk@...> wrote:

> **
>
>
> Hi
> Do any of you people here know of a quick and cheap way to tin copper PCB
> tracks before populating the board?
> With all the modern chemicals around these days theirs bound to something
> out there
> In the past have used the manufactured stuff which you just put in a bath
> for a while and job done but its to expensive.
>
> Thanks in advance
>
> Dave
>
>
>


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

Dave,

This works for me:

http://www.youtube.com/watch?v=NS62rik7eWA

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of David
Sent: Wednesday, August 14, 2013 11:01 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] silver coating

Hi
Do any of you people here know of a quick and cheap way to tin copper PCB
tracks before populating the board?
With all the modern chemicals around these days theirs bound to something
out there In the past have used the manufactured stuff which you just put in
a bath for a while and job done but its to expensive.

Thanks in advance

Dave



------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links

In article <kuhqq2+ce16@...>,
David <satdaveuk@...> wrote:

> Hi Do any of you people here know of a quick and cheap way to tin copper
> PCB tracks before populating the board? With all the modern chemicals
> around these days theirs bound to something out there In the past have
> used the manufactured stuff which you just put in a bath for a while and
> job done but its to expensive.

I suspect it will always remain expensive because of the price of Tin.

--
*Plain Text* email -- it's an accessibility issue
() no proprietary attachments; no html mail
/\ ascii ribbon campaign - <www.asciiribbon.org>

http://www.youtube.com/watch?v=w-YL6VmXvW8

On 15/08/13 19:27, Eddie Stassen wrote:
> I have had this bookmarked for years now, but have never got around to
> trying it:-
> http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=pt-BR&tl=en&u=http://www.py2bbs.qsl.br/banho_estanho.php&usg=ALkJrhj7fJXRaLTdNTmhinb2qUHkMr7fqg
>
> It describes tin plating before etching and seems quite simple.
>



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

On Thu, 15 Aug 2013 07:14:57 +0100 (BST), you wrote:

>Hi
>Thanks for the quick response
>See what I mean by price, if you start using that then just as well buy ready made PCBs and forget DIY
>Lets see if theirs any other ideas out there

The liquid tin that I use (MG chemicals) will last about a year's
production of boards, so the cost per board is not horrible. The same
size board (professionally done) is at least 22.00 USD, I'm going to
guess that the tinning adds between 50 cents and a dollar to the board
cost, and I suspect that this is a high cost based on a one year use.

The other way (which I have not heard of being done at home), is HASL,
Hot Air Solder Leveling. I can see several ways of doing it, but I
would worry about the stress on the epoxy bond due to all the heat.
The chemical tin plating is not a hot process.

Harvey

>
>
>________________________________
> From: James <bitsyboffin@...>
>To: Homebrew_PCBs@yahoogroups.com
>Sent: Thursday, 15 August 2013, 7:04
>Subject: Re: [Homebrew_PCBs] silver coating
>
>
>
>
>On 15/08/13 18:00, David wrote:
>>
>> Hi
>> Do any of you people here know of a quick and cheap way to tin copper
>> PCB tracks before populating the board?
>> With all the modern chemicals around these days theirs bound to
>> something out there
>> In the past have used the manufactured stuff which you just put in a
>> bath for a while and job done but its to expensive.
>>
>There is basically that (tinnit, liquidtin), and a product called "Cool
>Amp" http://www.cool-amp.com/cool_amp.html
>
>I've never found any reasonable "home brew" recipe for such a product.
>
>[Non-text portions of this message have been removed]
>
>
>
>
>[Non-text portions of this message have been removed]

For small boards I have used a solder and iron to
coat all the traces, then heated the entire board
to melt the solder then quickly used a cloth to wipe the
excess solder off the board.

The "pros" might dip or wave-solder the board
and then use a blast from a "hot air knife" to clean off
the excess....but that's speculation on my part.

I'd like to know how Far Circuits process their boards.

Charlie

On Thu, 15 Aug 2013 07:14:57 +0100 (BST) David Pickering
<satdaveuk@...> writes:

Hi
Thanks for the quick response
See what I mean by price, if you start using that then just as well buy
ready made PCBs and forget DIY
Lets see if theirs any other ideas out there

________________________________
From: James <bitsyboffin@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, 15 August 2013, 7:04
Subject: Re: [Homebrew_PCBs] silver coating

On 15/08/13 18:00, David wrote:
>
> Hi
> Do any of you people here know of a quick and cheap way to tin copper
> PCB tracks before populating the board?
> With all the modern chemicals around these days theirs bound to
> something out there
> In the past have used the manufactured stuff which you just put in a
> bath for a while and job done but its to expensive.
>
There is basically that (tinnit, liquidtin), and a product called "Cool
Amp" http://www.cool-amp.com/cool_amp.html

I've never found any reasonable "home brew" recipe for such a product.

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

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




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

Make your own tin electroless tin plating solution, see:
<http://www.voodooengineering.com/index.php/tinning/87-diy-tin-plating-solutiion>
All chemicals available on ebay

Malcolm

I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.
Ha-ktovet al ha-kir

--------------------------------------------

On Thu, 8/15/13, Harvey White <madyn@...> wrote:

Subject: Re: [Homebrew_PCBs] silver coating
To: Homebrew_PCBs@yahoogroups.com
Date: Thursday, August 15, 2013, 3:18 PM


























On Thu, 15 Aug 2013 07:14:57 +0100 (BST), you
wrote:



>Hi

>Thanks for the quick response

>See what I mean by price, if you start using that then
just as well buy ready made PCBs and forget DIY

>Lets see if theirs any other ideas out there



The liquid tin that I use (MG chemicals) will last about a
year's

production of boards, so the cost per board is not horrible.
The same

size board (professionally done) is at least 22.00 USD,
I'm going to

guess that the tinning adds between 50 cents and a dollar to
the board

cost, and I suspect that this is a high cost based on a one
year use.



The other way (which I have not heard of being done at
home), is HASL,

Hot Air Solder Leveling. I can see several ways of doing
it, but I

would worry about the stress on the epoxy bond due to all
the heat.

The chemical tin plating is not a hot process.



Harvey



>

>

>________________________________

> From: James <bitsyboffin@...>

>To: Homebrew_PCBs@yahoogroups.com


>Sent: Thursday, 15 August 2013, 7:04

>Subject: Re: [Homebrew_PCBs] silver coating

>

>

>

>

>On 15/08/13 18:00, David wrote:

>>

>> Hi

>> Do any of you people here know of a quick and cheap
way to tin copper

>> PCB tracks before populating the board?

>> With all the modern chemicals around these days
theirs bound to

>> something out there

>> In the past have used the manufactured stuff which
you just put in a

>> bath for a while and job done but its to
expensive.

>>

>There is basically that (tinnit, liquidtin), and a
product called "Cool

>Amp" http://www.cool-amp.com/cool_amp.html

>

>I've never found any reasonable "home
brew" recipe for such a product.

>

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

>

>

>

>

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

Malcolm Parker-Lisberg wrote:

>
>
> Make your own tin electroless tin plating solution, see:
> <http://www.voodooengineering.com/index.php/tinning/87-diy-tin-plating-solutiion>
> All chemicals available on ebay
>

That page lists the components as

* 0.5g Stannous Chloride
* 2.0g Thiourea
* 3.0g Sulfamic Acid
* 100.0 mL Distilled water

and further down that the proportions don't seem to be very critical.
Aside the fact that Thiourea seems like quite a nasty thing, the
Wikipedia does have this...

~~~
Silver polishing

According to the label on the consumer product, the liquid silver
cleaning product TarnX contains thiourea, a detergent, and sulfamic acid.
~~~

Come to think of it, I vaguely remember that this might have been looked
into by somebody previously.

Silver coating? Have you checked the cloud? ;)

Kerry


David wrote:

> Hi
> Do any of you people here know of a quick and cheap way to tin copper PCB tracks before populating the board?
> With all the modern chemicals around these days theirs bound to something out there
> In the past have used the manufactured stuff which you just put in a bath for a while and job done but its to expensive.
>
> Thanks in advance
>
> Dave
>

I think you meant silver lining?

On Aug 15, 2013, at 11:55 AM, Kerry Wentworth <kwentworth@...> wrote:

> Silver coating? Have you checked the cloud? ;)
> .
>
>
>



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

Hi James
Thanks
Shall try that , got the acid in stock , any ideas on where to get some cheap tin from?
Now thinking what can I scrap that contains Tin

Regards



________________________________
From: James <bitsyboffin@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, 15 August 2013, 13:43
Subject: Re: [Homebrew_PCBs] silver coating




http://www.youtube.com/watch?v=w-YL6VmXvW8

On 15/08/13 19:27, Eddie Stassen wrote:
> I have had this bookmarked for years now, but have never got around to
> trying it:-
> http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=pt-BR&tl=en&u=http://www.py2bbs.qsl.br/banho_estanho.php&usg=ALkJrhj7fJXRaLTdNTmhinb2qUHkMr7fqg
>
> It describes tin plating before etching and seems quite simple.
>

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




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

Hi Rick
That's what I been doing in the past , Only difference is I wrap the solder braid round the tip which gives you one hand free.
Was hoping to get away from that because apart from the fumes and chance of s/c to the track, the heat is a bit aggressive for the laminate.
Regards


________________________________
From: Rick Sparber <rgsparber@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Thursday, 15 August 2013, 12:59
Subject: RE: [Homebrew_PCBs] silver coating




Dave,

This works for me:

http://www.youtube.com/watch?v=NS62rik7eWA

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com]
On Behalf Of David
Sent: Wednesday, August 14, 2013 11:01 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: [Homebrew_PCBs] silver coating

Hi
Do any of you people here know of a quick and cheap way to tin copper PCB
tracks before populating the board?
With all the modern chemicals around these days theirs bound to something
out there In the past have used the manufactured stuff which you just put in
a bath for a while and job done but its to expensive.

Thanks in advance

Dave

------------------------------------

Be sure to visit the group home and check for new Links, Files, and Photos:
http://groups.yahoo.com/group/Homebrew_PCBsYahoo! Groups Links




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

The new lead free plumbers solder to spec. 99C contains 99.7% tin, the rest is copper.
I use it to make small quantities of bronze.

Malcolm

I don't suffer from insanity I enjoy it!
Mene, mene, tekel, upharsin
The writing is on the wall.
Ha-ktovet al ha-kir

--------------------------------------------

On Mon, 8/19/13, David Pickering <satdaveuk@...> wrote:

Subject: Re: [Homebrew_PCBs] silver coating
To: "Homebrew_PCBs@yahoogroups.com" <Homebrew_PCBs@yahoogroups.com>
Date: Monday, August 19, 2013, 6:13 AM


























Hi James

Thanks

Shall try that , got the acid in stock , any ideas on where
to get some cheap tin from?

Now thinking what can I scrap that contains Tin



Regards



________________________________

From: James <bitsyboffin@...>

To: Homebrew_PCBs@yahoogroups.com


Sent: Thursday, 15 August 2013, 13:43

Subject: Re: [Homebrew_PCBs] silver coating







http://www.youtube.com/watch?v=w-YL6VmXvW8



On 15/08/13 19:27, Eddie Stassen wrote:

> I have had this bookmarked for years now, but have
never got around to

> trying it:-

> http://translate.googleusercontent.com/translate_c?depth=1&hl=en&rurl=translate.google.com&sl=pt-BR&tl=en&u=http://www.py2bbs.qsl.br/banho_estanho.php&usg=ALkJrhj7fJXRaLTdNTmhinb2qUHkMr7fqg

>

> It describes tin plating before etching and seems quite
simple.

>



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



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

If tining before etching works well, I wonder why you don't see pre-tinned copper clad boards? I suppose it limits you choice of etchant.

Dave,

I agree. If I moved too slow, I would delaminate the tracks. Lately, my boards have been commercially made so I have been spoiled.

Rick

-----Original Message-----
From: Homebrew_PCBs@yahoogroups.com [mailto:Homebrew_PCBs@yahoogroups.com] On Behalf Of David Pickering
Sent: Sunday, August 18, 2013 10:25 PM
To: Homebrew_PCBs@yahoogroups.com
Subject: Re: [Homebrew_PCBs] silver coating

Hi Rick
That's what I been doing in the past , Only difference is I wrap the solder braid round the tip which gives you one hand free.
Was hoping to get away from that because apart from the fumes and chance of s/c to the track, the heat is a bit aggressive for the laminate.
Regards

A bit of anecdotal info on liquid tin plating. Some decades ago at a
company I was with we were doing PCBs that we tin coated with a
commercial electroless solution. The coating seemed fine and we
thought, "Great!" We would screen print a large lot of boards, etch
them, tin plate, and put on the shelf for later part stuffing by hand,
then solder by hand dipping the bds in a solder pot.

Now the down side. Within a relatively short time, the tin coating
seemed to get dull, and the solderbility with rosin based fluxes dropped
drastically (even worse than the bare copper) leading to faulty
soldering. You can observe the same phenomenon if you've ever found
some old resistors and try to solder the leads. It can be a bad
experience.

I attributed the problem to oxidation of the thin tin coating (or
tin/lead coating of the resistor leads) from the electroless tinning
process . Those oxides just don't solder well.

The solution we began using:
There are liquid organic acid fluxes designed for PCB soldering. We
switched to those. But several important steps must be strictly followed.
1) Press the soldering side of the board with components onto a sponge
soaked with the acid flux.
2) Immediately dip solder the board.
3) Then immediately drop the hot, just soldered board into a tub of
water. (Do not wait or store the boards, the consequences can be severe.)
4) Blow off the water and rinse again and blow off again. (Removing
excess water is important if using tap water as we were.)
5) Oven dry.

At this point I can immediately hear purists screaming, "Acid flux???"
Just let me say a few things. We were doing RC filters that required
extremely good surface resistance of the PCB before we coated the board
with solvent thinned epoxy to obtain and maintain the high resistance.
The process above gave us better results: bright, solid, well filleted
solder connections and incredibly consistent, very good surface
resistance of the PCB assemblies.

(Just a side tip, the best thing I ever found for moisture resistance
at that time on those PCBs was a solvent based silcone wax. However
the down side of that was that it was always a bit tacky and these
boards could end up in dusty environments, so we decided not to use it
in production. This whole area of moisture vs. resistance has come back
multiple times in my design career and could be thread in another
discussion list.)

Regards,
Charles R. Patton

Thanks charles
After reading your findings I may well not bother with it, just keep to the copper surface.
Normally when building equipment like metal detectors which are out in all sorts of environments I spray the finished populated board copper clad surface with electrical pvc spray.
Will just spray all boards lightly when the projects are finished to keep the shine there.
If you need to do any soldering at a later date it doesn't present much of a problem.
Thanks again



________________________________
From: Charles R Patton <charles.r.patton@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Monday, 19 August 2013, 18:23
Subject: Re: [Homebrew_PCBs] silver coating




A bit of anecdotal info on liquid tin plating. Some decades ago at a
company I was with we were doing PCBs that we tin coated with a
commercial electroless solution. The coating seemed fine and we
thought, "Great!" We would screen print a large lot of boards, etch
them, tin plate, and put on the shelf for later part stuffing by hand,
then solder by hand dipping the bds in a solder pot.

Now the down side. Within a relatively short time, the tin coating
seemed to get dull, and the solderbility with rosin based fluxes dropped
drastically (even worse than the bare copper) leading to faulty
soldering. You can observe the same phenomenon if you've ever found
some old resistors and try to solder the leads. It can be a bad
experience.

I attributed the problem to oxidation of the thin tin coating (or
tin/lead coating of the resistor leads) from the electroless tinning
process . Those oxides just don't solder well.

The solution we began using:
There are liquid organic acid fluxes designed for PCB soldering. We
switched to those. But several important steps must be strictly followed.
1) Press the soldering side of the board with components onto a sponge
soaked with the acid flux.
2) Immediately dip solder the board.
3) Then immediately drop the hot, just soldered board into a tub of
water. (Do not wait or store the boards, the consequences can be severe.)
4) Blow off the water and rinse again and blow off again. (Removing
excess water is important if using tap water as we were.)
5) Oven dry.

At this point I can immediately hear purists screaming, "Acid flux???"
Just let me say a few things. We were doing RC filters that required
extremely good surface resistance of the PCB before we coated the board
with solvent thinned epoxy to obtain and maintain the high resistance.
The process above gave us better results: bright, solid, well filleted
solder connections and incredibly consistent, very good surface
resistance of the PCB assemblies.

(Just a side tip, the best thing I ever found for moisture resistance
at that time on those PCBs was a solvent based silcone wax. However
the down side of that was that it was always a bit tacky and these
boards could end up in dusty environments, so we decided not to use it
in production. This whole area of moisture vs. resistance has come back
multiple times in my design career and could be thread in another
discussion list.)

Regards,
Charles R. Patton



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

Yes my very thoughts , I still use the old method with granules so its no go for me, hardly worth the hassle, shall give the whole Idea a miss.
When projects finished give PCB a nice clean then spray with PVC to keep the copper shining , also a good insulator, so does two jobs.


________________________________
From: fred27murphy <fred27murphy@...>
To: Homebrew_PCBs@yahoogroups.com
Sent: Monday, 19 August 2013, 12:52
Subject: [Homebrew_PCBs] Re: silver coating




If tining before etching works well, I wonder why you don't see pre-tinned copper clad boards? I suppose it limits you choice of etchant.




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

Dave,
I agree with your conclusion. Spray coating the copper just after the
resist has been removed is a good look and what I did with acrylic spray
at times in the past. The epoxy we used made rework almost impossible.
I haven't done much in the area of things that need re-work once built,
but generally I understand that acrylic or urethane spray coats are also
good and allow reasonable reworking. I do know that there was (still
is?) a patented PCB production process where after the resist was
removed, silk screening added, the board was coated with a "protective"
coating. The coating was thin, and basically a flux, but it also acted
as an oxygen barrier so the copper remained solderable for some period
of time. Personally I always felt this could be duplicated by using an
alcohol/rosin solution. (A cheap source of rosin is dance supplies.
Dancers put rosin on their ballet shoes.) Paint/dip your newly cleaned
board with the solution and you will have pre-fluxed it and protected
the copper surfaces from oxidation. Rosin by itself is dry and
non-sticky (be sure the alcohol is pure and not drug-store rubbing
alcohol which often has some mineral oil as a percentage of the
solution). A disclaimer here -- I've never done this myself as my
personal PCB needs have changed drastically from the days described
above. I make a one off prototype using toner transfer that I
immediately assemble by hand or I send off the files and have a board
house make a bunch.
Regards,
Charles R. Patton

things, On 8/20/2013 9:39 PM, David Pickering wrote:

>
> Thanks charles
> After reading your findings I may well not bother with it, just keep
> to the copper surface.
> Normally when building equipment like metal detectors which are out in
> all sorts of environments I spray the finished populated board copper
> clad surface with electrical pvc spray.
> Will just spray all boards lightly when the projects are finished to
> keep the shine there.
> If you need to do any soldering at a later date it doesn't present
> much of a problem.
> Thanks again
>
>
> ________________________________
> From: Charles R Patton <charles.r.patton@...
> <mailto:charles.r.patton%40IEEE.ORG>>
> To: Homebrew_PCBs@yahoogroups.com
> <mailto:Homebrew_PCBs%40yahoogroups.com>
> Sent: Monday, 19 August 2013, 18:23
> Subject: Re: [Homebrew_PCBs] silver coating
>
>
>
> A bit of anecdotal info on liquid tin plating. Some decades ago at a
> company I was with we were doing PCBs that we tin coated with a
> commercial electroless solution. The coating seemed fine and we
> thought, "Great!" We would screen print a large lot of boards, etch
> them, tin plate, and put on the shelf for later part stuffing by hand,
> then solder by hand dipping the bds in a solder pot.
>
> Now the down side. Within a relatively short time, the tin coating
> seemed to get dull, and the solderbility with rosin based fluxes dropped
> drastically (even worse than the bare copper) leading to faulty
> soldering. You can observe the same phenomenon if you've ever found
> some old resistors and try to solder the leads. It can be a bad
> experience.
>
> I attributed the problem to oxidation of the thin tin coating (or
> tin/lead coating of the resistor leads) from the electroless tinning
> process . Those oxides just don't solder well.
>
> The solution we began using:
> There are liquid organic acid fluxes designed for PCB soldering. We
> switched to those. But several important steps must be strictly followed.
> 1) Press the soldering side of the board with components onto a sponge
> soaked with the acid flux.
> 2) Immediately dip solder the board.
> 3) Then immediately drop the hot, just soldered board into a tub of
> water. (Do not wait or store the boards, the consequences can be severe.)
> 4) Blow off the water and rinse again and blow off again. (Removing
> excess water is important if using tap water as we were.)
> 5) Oven dry.
>
> At this point I can immediately hear purists screaming, "Acid flux???"
> Just let me say a few things. We were doing RC filters that required
> extremely good surface resistance of the PCB before we coated the board
> with solvent thinned epoxy to obtain and maintain the high resistance.
> The process above gave us better results: bright, solid, well filleted
> solder connections and incredibly consistent, very good surface
> resistance of the PCB assemblies.
>
> (Just a side tip, the best thing I ever found for moisture resistance
> at that time on those PCBs was a solvent based silcone wax. However
> the down side of that was that it was always a bit tacky and these
> boards could end up in dusty environments, so we decided not to use it
> in production. This whole area of moisture vs. resistance has come back
> multiple times in my design career and could be thread in another
> discussion list.)
>
> Regards,
> Charles R. Patton
>
> [Non-text portions of this message have been removed]
>
>

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

I have used the rosin laquer many times with good results.
It just takes slightly longer than regular paint to dry.

You can either mix your own colophony resin in denatured alcohol to paint
it on, or buy a spray can:
<http://www.banzaimusic.com/Solder-Lacquer-SK10-400ml.html>

I'm not usually one for spray cans, but this was very cheap for a big can
and will last forever.

I've also used it as a flux on old breadboard that was hard to solder with
good results.

You can use it as a general purpose flux to drip on stuff or dip wires in.

ST


On Wed, Aug 21, 2013 at 7:55 PM, Charles R Patton <charles.r.patton@...

> wrote:

> Dave,
> I agree with your conclusion. Spray coating the copper just after the
> resist has been removed is a good look and what I did with acrylic spray
> at times in the past. The epoxy we used made rework almost impossible.
> I haven't done much in the area of things that need re-work once built,
> but generally I understand that acrylic or urethane spray coats are also
> good and allow reasonable reworking. I do know that there was (still
> is?) a patented PCB production process where after the resist was
> removed, silk screening added, the board was coated with a "protective"
> coating. The coating was thin, and basically a flux, but it also acted
> as an oxygen barrier so the copper remained solderable for some period
> of time. Personally I always felt this could be duplicated by using an
> alcohol/rosin solution. (A cheap source of rosin is dance supplies.
> Dancers put rosin on their ballet shoes.) Paint/dip your newly cleaned
> board with the solution and you will have pre-fluxed it and protected
> the copper surfaces from oxidation. Rosin by itself is dry and
> non-sticky (be sure the alcohol is pure and not drug-store rubbing
> alcohol which often has some mineral oil as a percentage of the
> solution). A disclaimer here -- I've never done this myself as my
> personal PCB needs have changed drastically from the days described
> above. I make a one off prototype using toner transfer that I
> immediately assemble by hand or I send off the files and have a board
> house make a bunch.
> Regards,
> Charles R. Patton
>

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

I've used cool-amp a number of times in the past, and a little goes a
very long way - I found it very cost effective.
However, being silver, it tarnishes - relatively quickly. Once tarnished
it's quite painful to solder, so I found I had to use the cool amp, then
put on a coat of circuit lacquer immediately to keep it clean.

My other fav approach that's much cheaper; I got one of those camp
cooktops that takes the disposable gas cylinders, bought a $2 frypan
from a discount store and a few sticks of plumbers solder, the good old
60/40.
Stick the solder in the pan and get cooking (In a very very well
ventilated area such as outside in my back yard.
I made a scraper from a thin piece of circuit board about half as wide
as the frypan and put a handle on it at 90 degrees.

Made up my own flux in a spray bottle from citrc acid granules from the
supermarket and water, can use it with impunity. Just spray away on the
freshly etched board, nice and safe for you to get on hands etc without
worry.

Once the solder's hot and in a nice big pancake in the frypan, a quick
spray of the flux on the solder to get it's surface tension up, then use
the scraper to wipe off the muck floating on top (lead oxides?). Holding
the circuit board with a suitable implement just sit it on the solder.
It'll hiss and bubble around for a couple of seconds, then lift off well
before it starts to burn and delaminate.

I have a windscreen squeegee on hand to give a few quick wipes on the
board to take off excess solder, and it's all done with a very neat flat
solder plated surface.
If it's not quite coated completely, another hit of flux and a dip, with
another wipe. Can do this as many times as needed so long as the board
doesn't get overheated. With a little practice this is very quick,
usually needing only one go on each side of the board.

The solder definitely fumes, so keep your head back and preferably use
protection. I used to do this when I was younger and poorer and didn't
use any protection at all, other than holding my breath when I was close
to the pan (I can hold my breath comfortably for quite some time, so
wasn't worried about passing out and falling into the solder!)

I haven't tried this technique with lead free solder, although there's
no reason it wouldn't work other than probably needing a better flux
that's less cooling.

Cheers,
Andrew

On 15/08/13 4:04 PM, James wrote:
>
> On 15/08/13 18:00, David wrote:
> >
> > Hi
> > Do any of you people here know of a quick and cheap way to tin copper
> > PCB tracks before populating the board?
> > With all the modern chemicals around these days theirs bound to
> > something out there
> > In the past have used the manufactured stuff which you just put in a
> > bath for a while and job done but its to expensive.
> >
> There is basically that (tinnit, liquidtin), and a product called "Cool
> Amp" http://www.cool-amp.com/cool_amp.html
>
> I've never found any reasonable "home brew" recipe for such a product.
>
> [Non-text portions of this message have been removed]
>
>



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