Alain,
Yes I agree, I've worked with cyanide for years, with Gold, Silver, and
Copper.
I did get 'zapped' as I eluded to in the earlier message, we were reclaiming
gold from damaged contacts, everything was going along fine until the fume
hood vent fan stopped working. Just so happens it stopped two or so minutes
before I was walking by the reclaim room, walked right into a cloud of those
vapors...never did smell that distinct odor though, next thing I remember
was waking up with a man in a mask (doctor of the ER type) staring me in the
face telling me things would be fine...
Typically that distinct odor is present during the plating of cyanide
bearing metals. Can't recall ever smelling it during reclaim, of course we
were usually protected with respirators of some sort...
Franklin
----- Original Message -----
From: Alain Savard <[log in to unmask]>
To: <[log in to unmask]>
Sent: Thursday, March 16, 2000 4:56 AM
Subject: Re: [TN] Gold Removal
> Well, if I may address Ron's concern (who first posted on Gold).
>
> If I remember correctly it was originally stated that the boards had 20-30
> u" (0.51 to 0.76 um) of gold plated on Ni. That sounds still solderable
for
> common application. If you are in a rush, and are applying at least 4 mil
of
> solderpaste, you could most likely use these as is. I would very STRONGLY
> suggest that you send a corrective action to your bare board supplier for
> any future shipment. Keep good documentation of all corrective actions
> posted with a vendor.
> If you cannot use these for reason unknown to us... Good luck, I strongly
> suggest that you avoid using the stripping or any other method, this would
> most likely make the boards unreliable.
>
> Franklin, if you ever use cyanide there is a weak warning bitter almond
> smell before you get poisoned to the point of unconsciousness, be careful
> you rapidly get used to the smell and will not notice rising gas
> concentration. Also speaking from experience, I got out early after
closing
> the sash on the fume hood while holding my breath, got the worst headache
of
> my life, but all in all, Ok. Cyanide should only be used with proper
vapour
> extraction at the source.
>
>
>
> Alain Savard, B.Sc.
> Chemical Process Analyst
> CAE Electronics Ltd.
> e-mail: [log in to unmask]
>
>
> -----Original Message-----
> From: Franklin Asbell [mailto:[log in to unmask]]
> Sent: March 15, 2000 8:01 PM
> To: [log in to unmask]
> Subject: [TN] Gold Removal
>
>
> Cyanide in and of itself won't remove gold, it's a lot more detailed than
> that, and then controlling how much is removed is almost impossible.
>
> Speaking from experience, you won't even smell almonds, you might see a
> humid cloud drifting slowly away from the tank, and the next thing you'll
> see is the ER doctor telling you things will be just fine.
>
> 30 microinches of Gold won't affect solderability any different then 10
> microinches. What it might affect depending on your application is the
> electrical properties.
>
> If 30 microinches is simply intolerable then buff the gold tabs or pads
down
> to what you believe to be a tolerable level, unless you have access to an
> XRF or similar device though, you won't know how far you've gone.
>
> Sure, reject it all back to the fabricator, have them restart the job, put
> everything on a back burner, or better yet, find another supplier,
resubmit
> gerber, have them do it, of course you'll want to survey them first, gotta
> remember to schedule that before we give them the order.
>
> ~...hmmmm, wondering if I'm being too facetious, nah, not with this group,
> they can appreciate the humor in this....grinning~
>
> Franklin
>
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