Too cool and too dry. Maybe OK likes long shelf times. It's always a
mystery.
MoonMan
----- Original Message -----
From: Stephen R. Gregory <[log in to unmask]>
To: <[log in to unmask]>
Sent: Friday, October 08, 1999 6:03 AM
Subject: Re: [TN] Shelf Life
> In a message dated 10/07/1999 7:46:54 PM Central Daylight Time,
> [log in to unmask] writes:
>
> << TechNet,
>
> I need to tap a little expertise from the assemblers out there....
>
> I have a PWA kit to be built that has been sitting around for about 12-14
> months.
> No environmental storage of any kind, just in tubes and boxes in the
> stockroom.
> What dilemma's am I likely to encounter with these components, if any??
I
> suspect
> the boards will need to be baked, but normal duration or more based on
length
> of time on the shelf?? Any worry about warp and coplanarity?
> Any issues with components that have not been stored
> with any dissicant or anti moisture protection? Any worry about lead
> oxidation
> that requires cleaning/tinning for solderability/wetting concerns?
>
> Just wondering what kind of interesting things to expect or try and
avoid,
> if any.
>
> Any suggestions or comments greatly appreciated.
>
> Tks......DT >>
>
> Hi Darrel!
>
> I don't know if this will help you or not, but about 3-weeks ago, I got
the
> pleasure of wave soldering some boards (about 2-dozen) that had been
> partially assembled and had been sitting in tilt-racks for close to
> 10-months! There was SMT on top, some PTH, and also had components epoxied
on
> the bottomside (passives and actives) as well!
>
> Don't ask me why they sat around that long...something about the project
> being put on hold or something, I don't know. All I know is they brought
the
> boards to me and asked me to wave them. They asked before I waved, how did
I
> think they were going to do...I said probably like a pile o' poop, but I
> didn't have anything to lose so I'd give er' a go. I baked them and then
> waved them...used a OA flux. I musta' had the soldering gods looking over
me,
> they actually looked good! One of the supervisors came to look at the
boards
> while I was waving them to get ready for all the touch-up they were going
to
> do, but was amazed that they soldered as well as they did (I was pretty
> shocked myself, but I didn't show it...kinda' smug actually)
>
> Don't know if you'll be as lucky as I was...
>
> -Steve Gregory-
>
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