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Re: OT: Good lord some of this stuff is old.

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  • urrossum@att.net
    ... I m not Lee, but I ve tinkered a bit also... I m not sure that gold plating is easily practical, but tin plating might be. There are a variety of
    Message 1 of 16 , Jun 30, 2012
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      > Lee, I'm *not* real smart about this... but is there any way to gold
      > plate the leads *after* they are already attached to the chip??? It

      I'm not Lee, but I've tinkered a bit also... I'm not sure that gold plating is easily practical, but tin plating might be.

      There are a variety of electroless tin plating solutions available to tin home-made circuit boards after the etching step. I've used a couple, and they do work quite well. I don't know that they'd work on other base materials than copper, but I suspect that they would.

      A couple of the brand names I've used are "Tinnit", by Datak, and "Liquid Tin", by MG chemicals. Both of these work similarly: you mix the chemical, which comes in powder form, with water (preferably deionized), then you dunk the board (or in this case, the IC pins) into the solution. The tin plates out quite rapidly - within a couple of minutes - and then you remove the board and flush it with plain water. It's a very easy process, and seemed to produce reliably good results (which is more than I can say for the etching process I was attempting at the time).

      The solution only has a shelf life of a couple of months, although the powder's shelf life is indefinite. The product is cheap enough, too: about $8.00 for enough to plate 600 square inches of PC board (how many IC pins is that?).
      ~~
      Mark Moulding
    • Lee Hart
      ... Gold is hard to electroplate. Nasty, expensive, toxic chemicals. There are electroless plating methods where you basically just dunk the object in it; but
      Message 2 of 16 , Jul 1, 2012
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        Charles Richmond wrote:
        > Lee, I'm *not* real smart about this... but is there any way to gold
        > plate the leads *after* they are already attached to the chip??? It
        > would seem that the leads could be suspended in the plating bath
        > *without* submerging the chip itself... and a tiny electrode wire
        > could be soldered to the top of each lead to allow for the flow of
        > current *down* the lead into the bath. To prevent "sneak circuits",
        > it might be better to plate one lead at a time. :-)

        Gold is hard to electroplate. Nasty, expensive, toxic chemicals. There
        are electroless plating methods where you basically just dunk the object
        in it; but these only produce a gold flash; very thin and porous.

        I have a solder pot. What I've done on parts that aren't too badly
        corroded is to put flux on them, and dunk them in the solder pot.
        --
        An engineer can do for a nickel what any damn fool can do for a dollar.
        -- Henry Ford
        --
        Lee A. Hart, 814 8th Ave N, Sartell MN 56377, leeahart at earthlink.net
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