Solder Paste Fridge

MightyOhm’s laboratories have recently decided to start tackling more surface mount work. As part of this upgrade to SMD hot air reflow stations, they’re handling a lot of solder paste. Solder paste is happy at less than 50degF and above freezing, and [Jeff] didn’t want to chance that lead infiltrating his Manwich, so he built this solder paste fridge. The main unit is a standard 12V peltier based travel cooler. He attached a surplus PID controller with a K-type thermocouple to maintain the temperature while preventing the cooler from being always on. The only adjustment he really had to make was adding a bleed resistor to force the MOSFET to turn off. You can find more pictures of his project on Flickr.

4 thoughts on “Solder Paste Fridge

  1. Overkill for solder paste. I get my solder paste in small tubes from Zephyrtronics, and they have a formulation (they say) that works well at room temperature. I’ve stored the small tubes for months out in the open without problem. I leave the tip on, and the solder paste does dry up in the tip, but that acts as a seal. I just drop in a new tip further work. Also, their red tapered tips work best.

  2. reza – You are right, some paste is sold as not requiring refrigeration, but almost all solder paste will last longer if it is kept below 50F. The paste I bought requires refrigerated storage. If I was going to use it within a few weeks I wouldn’t worry about storage, but in this case I will probably be using the paste slowly over the course of a few months so I want it to last.

  3. Personally I think any risk of keeping a closed container of solder past in a refer that contains food would have to be minimal. Unless beer or other refreshments are kept cool also, that cooler takes up a lot of space, to keep what I assume to be a small amount of solder paste cool. I’d repackage it into a smaller cabinet. That would put less demand on the shop power supply as well.

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