Re: Gold plating the entire PCB

On Mon, 31 Mar 2008 12:05:24 -0700, Hattori Hanzo
<OutintheSnow@xxxxxxxxxxxxxxxxx> wrote:

On Mon, 31 Mar 2008 18:02:40 GMT, qrk <SpamTrap@xxxxxxxx> wrote:

MooseFET wrote:

Lately, I've been looking again at gold plating the entire PCB. It
makes a nice chemically stable layer on top of the copper. With the
price of copper these days, changes are the copper on the PCB will
cost more than the small amount of gold involved.

If you don't care about long term reliability or your selling to
audiophools

That has nothing to do with it, dip***.

(everybody knows that gold is the best conductor!) gold
plate to your heart's content.

Strike two! SILVER is the best conductor. Gold and Platinum have the
best oxidation characteristics, hence their use on contacts.


Normally, if you want to gold plate your pcb, use "immersion gold"
plating.

I think you're an idiot. Every circumstance is different, so
"normally" doesn't ever apply.

This puts a very thin layer of gold over the pads. I'm told
that the solder joint is mechanically good since there is so little
gold that gets absorbed into the solder joint.

"You're told"? Whom is it handing you this horse***? There are REAL
numbers. We typically measure these things in micro-inches.

Thick layer of gold
will create an intermetallic layer with solder which can cause solder
joint failure due to embrittlement.

Wow. You actually remembered something correctly.

You also want to nickel plate
before gold plating. Gold over copper is an unhappy mixture.

You might have a little experience in this realm, but I still have my
doubts.

Theses days with BGAs and 0402 parts and smaller, immersion gold or
silver is recommended.

You just make *** up as you go all the time? EVERY PCB situation is
different.

HASL (tin plating) leaves too much material on
the pad which messes up the volume of solder on the pad.

HASL hasn't been used in years. Even solder plated PCB assemblies have
SMOBC treatment these days.

You forgot to take your meds. Dose up and re-read.
.

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