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solder paste storage to -40 degree celsius

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#71583

solder paste storage to -40 degree celsius | 14 January, 2014

Hi

I have solder paste that suppose to be stored to 0 - 10 degree celsius. However due to broken fridge, we decided to stored on -40 degree celsius freezer. Does the solder paste still good to be use?

Please help.

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#71584

solder paste storage to -40 degree celsius | 14 January, 2014

I don't know. What does your paste supplier say? You can run tests * That you used to qualify this paste in the first place. * According to IPC J-STD-005A Requirements for Soldering Pastes * Using your toughest stencil to print this paste on a bare copper board, reflowing the board and then evaluating the quality of the solder blobs on the board.

Other thoughts are: * You might need to monitor the quality of solder connections of this paste more often than usual * It would be interesting to have you report your findings back to us here on SMTnet

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#71585

solder paste storage to -40 degree celsius | 14 January, 2014

This is according to Kester

What happens if the paste gets too cold? At temperatures below -15oC (5oF), one or more components of the solder paste may crystallize, producing a non-homogeneous appearance to the solder paste. Such non-homogeneity may be irreversible, meaning that the paste would be unusable.

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#71586

solder paste storage to -40 degree celsius | 14 January, 2014

#71587

solder paste storage to -40 degree celsius | 15 January, 2014

If the supplier has prescribed the storage temperature between 0 - 10 degree celsius, then it means that it work effectively if stored in that temperature range.

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#71588

solder paste storage to -40 degree celsius | 15 January, 2014

Just completed doing the evaluation. The reflow looks good. No unreflow observed. Meaning to say the solder pastecan be use right.

Thanks.

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