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SMT electronics assembly manufacturing forum.

Solder Paste Expiry



Solder Paste Expiry | 5 November, 2004


I would like to know the maximum no. of hours that an opened solder paste and then closed for sometime but never returned to the fridge?


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Solder Paste Expiry | 6 November, 2004

Depends mainly on your paste. Evaporation of alcohol/flux is your main concern. But most name brands last with no problem. What's "some time"? If it's hours, no problem - if it's days possible problems with evaporation -if it's weeks, just buy some new paste. Remember, refrigerating paste is only done to reduce seperation of metal and chemistry. Your paste is not like meat and "spoil" or "turn rotten" if not frigged.

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Solder Paste Expiry | 8 November, 2004

In addition to type of paste, it is also dependant on the enviroment conditions. When you say open jar are you implying that the jar is left open all day and then at the end of shift it is closed back up? Jars should only bve open for about 30 secs at a time so you can stir and apply to stencil, other than that it should be kept closed. We have used paste for days under these circumstances.


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