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From:
David Hillman <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, David Hillman <[log in to unmask]>
Date:
Fri, 13 Mar 2015 15:47:55 -0500
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And I will echo Mike's details! Rockwell Collins conducted a series of
tests demonstrating that 20 year old fluxed core wire was as good as the
day it was produced (published at the  SMTA ICSR Conference in 2010) - as
Mike discussed, sealing an organic material in a lead container is a great
idea. The primary issue is that the industry's ISO type protocols require
that a material have a "shelf life value" and most auditors will not accept
"indefinite"as a valid response. I do know that Alpha has detailed on some
of their cored wired technical datasheets that the shelf life is indefinite
with valid storage conditions but the warranty is only good for two years.
I think that is a perfect solution to the issue, just wish all of the wire
solder suppliers would do that so we could have an industry "standard
practice".

Heck, who knows, maybe this TechNet discussion will start a trend!

Dave Hillman
Rockwell Collins
[log in to unmask]

On Fri, Mar 13, 2015 at 2:41 PM, Mike Fenner <[log in to unmask]> wrote:

> Pragmatic answer.
> I don't know if the actual shelf life of electronic grade flux core solder
> wire has been established, or ever will be. Nor bar solder for that matter.
>
> If you wanted to preserve an organic compound packing it in a lead or lead
> alloy container would be a good way of doing it, and some activators are
> not
> a million miles from the type of things used as preservatives in foods. So
> that's the flux taken care of. So far as the metals are concerned the lead
> on our church roof has been there up to eight centuries in all weathers. It
> has oxidised a little and this would be the case for high lead alloys. The
> wire can be cleaned easily enough by drawing it through a wipe.
>
> For what it's worth I have accumulated a number of odd wire samples over
> the
> years , all perfectly OK. The oldest in my garage dates from the early 70s
> and has outlasted its spool which has corroded somewhat, but the wire still
> works well, bit smokier than modern types, but that's age of formulation
> not
> age.
>
> I don't doubt that the IPC has said what it's said because it was under
> pressure to say something as people these days want a spec to work to.
> Similarly manufacturers will give a shelf life - not as some dastardly plot
> to increase sales - but because again people are looking for a number. I
> recall telling someone the shelf life of bar solder was effectively
> forever,
> explained why and was pressed for a number as the system required one. So I
> said in practical terms it would outlast the records so that's
> indefinitely,
> put what you like. I was then asked to quantify forever/indefinite. So I
> said 50 years and was told that that number was too big and asked if I
> could
> agree 5 - which I did to end the call. A week later I was asked to support
> the 5 years statement with data by caller's colleague as he said it should
> be more. Easier just to write a number to start with.
>
> Regards
>
> Mike
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Ricardo Moncaglieri
> Sent: Friday, March 13, 2015 1:39 PM
> To: [log in to unmask]
> Subject: [TN] Solder Wire Due Date
>
> Colleagues,
>
> Question:
> Is there any specific concern about solder wire due date IPC quality
> level 1?
> As per J-STD-001 3.2.2 (including J-STD-006) it is not specified any
> requirement for Level 1 about solder purity which could be affected from
> due date (oxides growing etc).
> Which is the main concern related on solder due date to be taken into
> account?
>
> Have been reading some papers beside the specific IPC stds mentioned
> upper, and all comments states something like this (or approach similar
> concepts):
>
> "The presence of additional oxidation may be visible on the surface of
> the wire. You may find that the oxidized surfaces are only on the outer
> portion of the cored wire, meaning that you could unspool the wire until
> you get down to the less oxidized material.
>
>
> You can determine if the expired cored wire is still usable by simply
> trying it - and if you aren't getting the typical amount of soldering
> action (wetting speed, spread) that you normally expect, this means that
> the age of the cored wire could cause a performance issue.
> I have never heard of a reliability issue related to using cored wire
> past the expiration date of the cored wire. The caveat to that statement
> is that if the solder is excessively oxidized, the operator may feel
> forced to supplement the cored wire with more liquid flux than would be
> considered typical or acceptable."
> Keep awaiting for your comments.
> brgds,Ricardo
>
>
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