Homebrew_PCBs

I don't know if you want this around if you have kids, but MG
Chemicals makes "Liquid Tin" -- which plates in 5 minutes. The
contents are nasty -- fluoroboric acid and stannous fluoroborate.
Allied Electronics sells it, but not that they will ship all
chemicals separately and you pay a UPS surcharge for Hazmat. It's
expensive at $27 for 17 ounces.

Why not silver plate your PCB. It's easy to do with "CoolAmp".
CoolAmp silver plating powder is applied to a clean PCB with a damp
cloth pad. Simply dip the damp cloth pad into the powder and run onto to
the PCB, in about 30 seconds you will have a silver plated circuit
board, wash with water. I save the cloth pad in a plastic bas and for
small circuits, I find it still "plates" days later by simply wetting it
and not having to apply more CoolAmp powder. Soldering qualities are
improved also.
The plating is pure silver, this product is normally used to silver
plate very large circuit breaker switch contacts to reduce the contact
resistance. I originally ordered a 4 ounces and paid $70 for it. that
was 3 years ago and it's about half way used. I do a lot of prototype
PCB's in a year. $70 sounds expensive but compared to "Tin-It" that I
was using, CoolAmp is CHEAP.
This link shows my CNC stepper motor driver PCB plated with CoolAmp. The
plating does not turn black like silver does. This board is one of the
first I did three years ago, and last I looked at it (it's enclosed) it
was bright and shiny.
http://hans-w.com/stepper_connections.jpg
There are other examples at my site http://hans-w.com

Link to CoolAmp Description in the Thomas Register, and contact infor
for the manufacturer:-
http://www.thomasregister.com/olc/cool-amp/coolamp.htm

For High Frequency applications I think CoolAmp will provide same
reduced surface resistance as normal silver plating does.

Hans W


caveteursus wrote:

> I don't know if you want this around if you have kids, but MG
> Chemicals makes "Liquid Tin" -- which plates in 5 minutes. The
> contents are nasty -- fluoroboric acid and stannous fluoroborate.
> Allied Electronics sells it, but not that they will ship all
> chemicals separately and you pay a UPS surcharge for Hazmat. It's
> expensive at $27 for 17 ounces.
>
>
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[Non-text portions of this message have been removed]

Anyone tried PCB Tin Plating with Tin Chloride, Thiourea and Sulfamic Acid? I just tried and I got only few tin spots .  Any suggestions pls.  

Thanks caveteursus and Hans for your kind suggestions.  But unfortunately neither "CoolAmp" nor "Liquid Tin" available in my country (Sri Lanka) :( Any other suggestions highly welcome.  Anyway thanks again for your feedback.    

I am in the process of trying to do it based on this man's work:

http://transistor-man.com/electroplating_busbar.html I had on hand a small roll of "lead free" solder and gave it a try.  The first test is very positive, but I had to increase the current density to 13.5 A/M2 instead of the 10 that he suggested. Also noted the current he used was not based on the 10A/M2 that he suggested so it looks like it will take a bit of testing to get it right.
I also looked up the recommened current density on Caswells site and they recommend 15.5 A/M2.

The power supply I was using was flaky so just got a new one in yesterday and plan more testing in the next few days.

Art
Country bubba


At 09:03 AM 9/18/2013, you wrote:

I have had some success with the tin plating product sold by Rapid Online but it requires the copper surface to be extremely clean or results are patchy. Once made up the solution last for about six months in a well sealed plastic container (supplied).
 
Regards
Bob
Bob F Burns G3OOU
C Eng, FIET, MSE
G-QRP 6907
Secretary of Crystal Palace Radio & Electronics Club: www.g3oou.co.uk
Technical web site: www.qsl.net/g3oou
@BobFBurns on Twitter: http://twitter.com/BobFBurns

Has anyone used plating pens? I've found discussions about using them for silver plating. Not sure if it's possible with tin.

Some links (you can tell I'm UK based):

http://www.intertronics.co.uk/products/chun.htm

http://www.goldn.co.uk/gold-silver-pen-plating-kit/

Using a silver plating pen doesn't look like a cheap option, but if it works well and is easy and clean then it might be worth it.

I have used the Sulfamic acid, Thiourea, and stannous chloride since 1973 to tin plate boards.

If you are having problems, make sure your chemicals he correct ones and fresh. You need Tin(II) chloride SNCl2 CAS 7772-99-8, Thiourea SC(NH2)2 CAS 62-56-6 and Sulfamic Acid H3NSO3 CAS 5329-14-6

Formula for various batch sizes:

100 mL 50 mL 25 mL
----------------------------------------------------
.5g Stannous Chloride 250mg 125 mg
2.0g Thiourea 1g 500 mg
3.0g Sulfamic Acid 1.5g 750 mg
100.0 mL Distilled water 50ml 25ml

Use a fresh batch each time the stuff doesn't last more than a day or so. Heat to 80 to 120 degrees and make sure you copper board is very clean and bright.
Read the MDS for the chemicals especially Thiourea it has health risks and is fairly nasty.
Craig