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Solder Paste Storage and Control

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#57124

Solder Paste Storage and Control | 30 October, 2008

Guys,

So I recently started working for a small CM in Southern N.H. We currently use 2 Magic Chef Mini wine friges to store the solder paste (63/37, RoHS).

I've been monitoring the room temp (and humidity) and the frige temps all this week. The procedure I just wrote for paste storage and control follows the standard 40 degrees F +/- 5 degrees F manufacturer guidelines. The room temps currently average 72-74 degrees F. The frige temps average about 55 degrees F (+/- 4 degrees F). This is not good.

My question to you guys is what manufacturer/model frige(s) are you using to store your paste, and how were you able to verify that it could consistently maintain temps in line with the paste manufacturer's specs?

I want to resolve this and move on to paste selection and evaluation without having to recommend spending $1K+ on this.

Your feedback would be greatly appreciated.

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#57125

Solder Paste Storage and Control | 30 October, 2008

Your fridges can't be temperature adjusted? We've always just used "pre-owned" kitchen fridges and set them where we want them.

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#57126

Solder Paste Storage and Control | 30 October, 2008

Steve,

I forgot to put in the original post that the 2 friges are set on the maximum coldness settings.

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#57127

Solder Paste Storage and Control | 30 October, 2008

We use a normal off the shelf (Best Buy) mini fridge. As far as the temp readings, I got some USB dataloggers from Omega and stick them in there. Download the data to your PC every couple of weeks (Outlook reminder). I also use these for our Nitrogen cabinets...

Will spit you out a file like what is attached...

http://www.omega.com/pptst/OM-EL-USB-1.html

Attachments:

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RLM

#57128

Solder Paste Storage and Control | 30 October, 2008

Are these real refrigerators using a compressor and refrigerant, or are you using the thermoelectric cooling type. Thermoelectric's can only cool to about 30 F below ambient on there very best days. Any refrigerator that uses refrigerant should be able to get to 40F.

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#57129

Solder Paste Storage and Control | 30 October, 2008

RLM,

These refrigerators are not the thermoelectric type. Standard compressor/refrigerant.

What I'm seeing for most units of this type (in the little hard info available) is that most mini-friges will only cool down to about 20-25 degrees below ambient temps. A consistent 50 degrees would be close but no cigar. especially as I'm told the ambient temps reach >80 degrees F in the Summer.

Also, "It is not recommended to store foods which must be kept at below 40� F for safe storage". Obviously we're not storing food, but the point is still valid.

jdumont,

Thanks for the data. I have a couple of Extech digital thermometers I'm using in the friges now and an Extech datalogger tracking the temp and humidity in the room.

Maybe I'll stick the datalogger in one of the friges to verify the data.

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#57130

Solder Paste Storage and Control | 30 October, 2008

http://www.bestbuy.com/site/olspage.jsp?skuId=5435031&type=product&id=1149205187587

This is what we have and never had an issue. Its only set to about mid range on the dial and easily holds 40 F.

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