In a message dated 2/15/2001 8:46:23 PM Central Standard Time,
[log in to unmask] writes:

<< Solder paste reuse: does anybody has this practice? Obviously, my solder
 paste supplier does not recommend it.

 Nicolas Ortiz
 Process Engineering Group Leader
 Conexant Systems >>

Hi Nicolas,

Your supplier is not recommending it to in order to sell you more paste, it
is a valid recommendation.

I'm not quite sure about what you mean by "reuse", but if you mean taking
paste off a stencil, putting it back in a jar after a run, and then keep
using it, that's a bad idea.

The paste will absorb moisture, the volatiles in the paste will evaporate,
basically changing everything about the formulation of the paste = not
performing like it's been advertised to do...I don't know of any manufacturer
of solder pastes that would recommend to reuse solder paste after it's been
dispensed on a stencil...

I do however, understand your concern about the expense when throwing away
solder paste...it's not cheap, anywhere from $50.00-75.00 for a 700-gram jar.
But you can recover some of the costs through recycling...Alpha/Fry Metals
will recycle solder paste and give you back the money that the tin/lead
market prices are at the time you turn it in...

Bottom-line, don't "reuse" your solder paste...it'll bite you...

-Steve Gregory-

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