Hi Mike and folks! There is plenty of data showing that cardboard,
rubberbands and tape can cause solderability issues due to sulfur or
chlorine contamination. There is a really good photo of such an example in
the IPC-4553 Immersion Silver plating specification (Figure 3-7). However,
the key point is one that Mike, Bob, and Jack detailed - certain finishes
are more prone to this type of degradation (aka silver or copper) and the
initial quality of the surface finish is an important variable on much of
"contamination" exposure can be tolerated. Both Mike's NOS and Bob's
reeled components demonstrate that avoiding cardboard is a good practice
but not a necessary practice if other parameters are working for you.
Dave
Mike Fenner <[log in to unmask]>
Sent by: TechNet <[log in to unmask]>
06/06/2012 10:47 AM
Please respond to
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Subject
Re: [TN] Electronic assemblies packaging
Dampness will improve the static dissipation properties of the card, for
other properties I offer a personal observation rather than rigorous data:
I own an old car (~50 years) and am always on the look out for what is
known
as N.O.S. parts. Especially electrical parts like switches, dials/gauges
etc. For non classic car fans, "NOS" means new old stock. In other words
the
parts are also 50 or more years old, but have not been used so are in
original packing - cardboard. [This is not for sentimentality but because
the original old stock is better made than modern reproductions and does
things like work and fit.] Terminations on this old stuff are nearly
always
perfectly clean and shiny, although the boxes are usually a little sad.
Soldered joints are bright, but what would constitute tracking (very thing
copper pieces in some gauges) is usually dull.
50 years is about 40 more than the planned storage time and predates
nearly
all auto electronics, so can't comment on that. [Although I do have a
rather
modern late 1960s early 70s radio complete with push button tuning -
string
operated of course!]
Regards
Mike
Bonding Services & Products
M: +44 [0] 7810 526 317
T: +44 [0] 1865 522 663
E: [log in to unmask]
-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Jack Olson
Sent: Wednesday, June 06, 2012 3:23 PM
To: [log in to unmask]
Subject: Re: [TN] Electronic assemblies packaging
Maybe I missed something, but that article didn't seem too enlightening.
Isn't it common knowledge that bare copper will tarnish?
and that silver coatings need to be protected with "silver saver" paper or
some type of good packaging until used?
(a "no brainer" study, if you ask me...)
It might not be wise to store "piles of reels" in cardboard boxes for
nearly
a decade,
but the component termination plating on those probably aren't copper or
silver.
I thought the original question was about shipping final product, not
about
wettability.
What is the danger of shipping AFTER SOLDERING in cardboard?
Maybe not the cardboard,
probably the moisture.
Jack
.
On Tue, 5 Jun 2012 20:33:27 -0400, Robert Kondner
<[log in to unmask]> wrote:
>Hi,
>
> Having used card board shelving supplies for years I was curious. I
heard
>about solderability issues but never noticed issues. So I was wondering
if
>this was hogwash or not.
>
> So I did a little web look up and found this note:
>
>www.kondner.com/files/cardboard_soldering.pdf
>
>Now I have parts in plastic bags and the cardboard containers do have
small
>holes, that might help vent. Our temperature is lower probably around 20
-
>23C. But the result in the paper were a BIG surprise. Likes like it is a
>real issue and NOT hogwash.
>
> I have a pile of 1206 reels that have been sitting in a card board box
>without plastic bags for maybe 10 years. I will need to take a look.
>
>Bob K.
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