On Fri, 7 Aug 2009 08:49:15 +0100, you wrote:

>>Does the "expiry date" on the tube make that much of a
>>difference in hobbyist use? I mean, in production I sure
>>as hell wouldn't be using 9-month-expired paste, but is
>>there a point at which solder paste becomes good for
>>nothing more than dustbin filler?

It varies with brand and storage condtions, but in general the dates will be very conservative.
Solvent evaporation and moisture ingress are the main issues, so sealed tubes kept cool can be
expected to last a few years.  It's pretty obvious when it's gone too dry as it becomes impossible
to get out of the tube. 

>Discussion on this list, in the past, has suggested the two 'big' problems 
>are the solvent evaporating, and the balls of solder settling so the paste 
>is no longer a constant consistency. The first problem is 'fixed' by adding 
>some suitable solvent, and for the second, various people have reported 
>success using an ultrasonic cleaner as a vibrator to stir the paste up in 
>the tube.
>
>>Also, those syringes (in the ebay ad) seem to be missing their plungers...
>
>Probably meant for automatic pneumatic dispensers then, which will have the 
>plunger on the hydraulic piston. 

Yes - but not a problem to use a plunger from another syringe, or any suitably shaped stick to push
with. If anything these syringes are better as the end is capped, so any evaoration by seepage past
the plunger is contained.

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