In a message dated 10/18/2004 6:17:55 PM Central Standard Time,
BWeiss@... writes:
What does one use to protect the copper when your finished with the board?
Tinning?
BW: Yes, the bare copper SHOULD be at least tinned, except for "throw-away,
one-each" hobby-PC work that doesn't have to last. A firm I THINK I read is
no longer with us, Kepro, sold a "Tinnit" solid which, when dissolved in hot
water, would "electrolessly" tin all the bare copper that came into contact
with it. I used this religiously for a time until TWO things: First, the
stuff just plain "went bad" (which I learned later it DOES), and then, I
couldn't get in touch with that firm any longer, and seems I READ (here?) that
Kepro was either out of business, or had at least ceased selling to "home shop
folks".
What I always do when doing an "important" board is solder nicely, then
using either Acetone or lacquer thinner and an old toothbrush (using the one you
actually still use is not tasty!) and "scrub off" all the solder-flux ("rosin
core") melted all over the board. Be very careful not to let that goop run
into IC sockets, etc.! Hold the board essentially vertically over a metal
pan large enough to catch drippings, and give you also a place to dip/re-wet
your brush. I do this "solvent brushing" ONLY on the "solder side"! If there
are nasty spots on the top (where you soldered a "through-hole"
resistor-lead, etc.) I use a tiny piece of paper napkin and swab-off that tiny spot of
nasty on top, here and there, being super careful not to use so much that it
runs all over, into sockets and non-hermetically-sealed components, etc.
Then I "mask off" all the IC-sockets, trim-pots, later-to-be-soldered pins,
etc., and then clear-spray the board, both sides, parts and all. Then
carefully remove all that masking tape, and use a fresh piece of it to "pull off"
any nasties that peeled off onto the board as you removed the masking. This
keeps the nasty atmosphere off the "shiny metal", but, as you had so carefully
masked the sockets, etc., you can still plug in IC's, certain of good
contact.
Takes some patience and experience. Did I say patience?
Lotsa luck! Jan Rowland
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