I don't know if this is obtainable for most people or not, but what I use is "liquid tin" from M.G. Chemicals (www.mgchemicals.com)
I don't know what it really is, but its awesome stuff. The 500 ml bottle I have has lasted longer than I can remember (many years) as I don't throw it away after using it. I have even done "spot rework" with a cotton swap of the stuff - just brush is on like paint and it instantly plates. The solderability is great, I do SMT stuff by hand all the time and have no problem making connections and good looking joints.
Peter
JanRwl@...05/20/2003 12:37 PM
To:
Homebrew_PCBs@yahoogroups.com@Internet
cc: (bcc: Peter Welty/Americas/NSC)
Subject: Re: [Homebrew_PCBs] Tin plating...
In a message dated 5/19/2003 3:29:52 PM Central Standard Time,
nuno-t@... writes:
> Iâ m also interested in such a formula. Iâ ve heard that silver nitrate is
> used to this purpose. Is this truth? Does anyone have more info?
>
TIN is in a completely different apartment on the Periodic Table. AgNO³ will
"plate" copper with NO DC applied. It does NOT improve solderability at all,
and will COST you more than the PCB itself, PER SIDE! I recall when I was in
high school, in '61, one fluid ounce of concentrated AgNO³ solution cost
about $6.00, so that may well be $30 today for ONE fluid ounce! Dunno...
Tin (Sn) is fussy, but Kepro, if my feeble old mind serves me, sells a
yellow/white crusty chemical which "electrolessly" plates tin onto copper,
and the only "energy" required is a bit of heat. This stuff can be used over
and over until depleted, but it DOES "go bad" with time, as I recall. It
also leaves a relatively THIN tin-plating on copper, but it DOES improve
solderability if done SKILLFULLY (i.e., "cleanly"). I no longer have Kepro's
address, but I IMAGINE they can be found on the Internet with an everyday
Google search.
Jan Rowland
[Non-text portions of this message have been removed]
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