'Tinning' Project PCB's

Discussion in 'General Electronics Chat' started by Maketronic, Dec 4, 2011.

  1. Maketronic

    Thread Starter Active Member

    Mar 21, 2009
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    Hi All

    I just made an exciting discovery for 'tinning' my home made pcb's.
    Many people say that it is too much hassle to tin your pcb's at home, indeed the tinning solution can be quite expensive and is very toxic.
    There is a commercially available silver plating called which silver plates your pcb's which got me thinking.
    I looked into making my own solution with Silver Nitrate (very expensive), making my own solution (very expensive and very dangerous).

    A number of people sell solutions on eBay for Silver Plating or re-plating your silver goods, a number of which are electro less (ie. just apply, wait, then polish off)

    I bought such a solution called Instant Silver Amazing Silver Plating Formula for $18 usd including shipping.

    When it arrived I tested it immediately, I whipped up a test PCB by the toner transfer and Hydrochloric/ Peroxide method then applied it as per the instructions.
    I sprayed the solution on, waited a minute or so then polished it off.

    The solution seems to work reasonably well and was no problem to solder.

    I have attached a photo of the test PCB. The porous looking solid area it a problem with my toner transfer method, my laser printer does not seem to like printing solid blocks of black.

    The solution came in a 45ml spray bottle, I believe there will be much more efficient and less wasteful ways to apply but these are early days.

    I would be interested to any body elses experiences or feedback.

    Regards

    Bruce
     
  2. thatoneguy

    AAC Fanatic!

    Feb 19, 2009
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    Your QFP has shorted pins, is that from the etching or the plating?
     
  3. Maketronic

    Thread Starter Active Member

    Mar 21, 2009
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    hi, a bad etch, not a bad plate.
     
  4. Maketronic

    Thread Starter Active Member

    Mar 21, 2009
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    See this attached jpeg here.

    Sorry first photo was a rush job and poor example, see this instead
     
  5. Wendy

    Moderator

    Mar 24, 2008
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    Do you conformal coat after the fact?
     
  6. Maketronic

    Thread Starter Active Member

    Mar 21, 2009
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    In the past I have just used the bare copper boards, but yes it is my intention to use a lacquer coating on the board afterwards.
     
  7. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    I used silver plate solutions with mixed results. Some did not solder flow well after.

    All the techs we had used this same trick:

    To tin a PCB, use a scotchbrite pad to buff it absolutely shiny and then BEFORE YOU DO ANYTHING ELSE, spritz the copper with a touch of conformal coating. Let dry, then use a solder iron to tin the board. Do NOT remove conformal coating before tinning, it will burn away as you go.

    If you don't coat it, the copper actually oxidizes from the iron's heat as you are tinning and stops accepting solder well. The coating keeps it tinning perfectly. It will also protect it indefinitely if you want to store the board before tinning.
     
  8. bountyhunter

    Well-Known Member

    Sep 7, 2009
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    A clear urethane spray is probably better if not using dedicated conformal coating spray.
     
  9. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    Maketronic- do you have a link for the silver spray?

    And more details would be nice, if you don't mind answering some questions. :)

    1. Is it a silver coloured coating (like a paint) or a liquid that causes the silver to be plated on?
    2. Is it actual silver (if the ingredients are listed)?
    3. How much gets used up to do a board? Cost per board?
    4. Does it impede soldering or aid soldering compare to bare copper?
    5. Does it smell or emit nasty fumes when coating, or soldering?
    6. Is it structurally sound on the tracks (won't easily rub off)?
    7. Does it tarnish or corrode over time (try putting saltwater or vinegar on it)?
     
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