Electronics Forum | Fri Apr 20 03:04:24 EDT 2018 | tsvetan
We usually replace stencil when we start to get problems with the solder paste printing i.e. uneven solder paste deposit etc. Until then it doesn't matter how many years ago it's manufactured, but how many prints it passes and if the operators didn't
Electronics Forum | Mon Jul 26 20:57:55 EDT 2010 | davef
It depends. Read "Evaluating Solder Paste - not an Option" by Phil Zarrow, ITM Consulting
Electronics Forum | Mon Dec 17 09:38:27 EST 2012 | cyber_wolf
Why scrap paste if there is no degradation of performance? Do your own study to determine this.
Electronics Forum | Mon Jul 26 20:31:59 EDT 2010 | engr
When hand placing SMT components what is the working time before the solder paste become unusable (dry)?
Electronics Forum | Thu Nov 03 09:20:29 EST 2005 | russ
Unforunately, the only one who can give you that answer is the manufacturer. They are the only ones who know what is in their paste and how it reacts to different situations and conditions.
Electronics Forum | Mon Dec 17 08:34:58 EST 2012 | emeto
I would scrap it. As you said part of it is going to be old paste. All manufacturers don't recommend mixing old with new paste because you change the rheology of the paste.
Electronics Forum | Thu Apr 12 20:27:10 EDT 2001 | davef
Tantalum caps degrade over time. You should not be seeing "chipped-off & cracks" regardless of the age. This should not be a shelf-life issue, unless you are storing them in an aquarium. Tell us the story. Solderability is a shelf-life issue and
Electronics Forum | Tue Jul 02 16:04:08 EDT 2002 | russ
We normally disregard what the "tech" sheets say. A lot of it has to do with your printer settings, prints per hour, placement time, stencil cleaning procedures etc... Just another wrench to throw in, We have noticed lot to lot paste differences al
Electronics Forum | Tue Jul 27 08:03:55 EDT 2010 | scottp
You have to figure this out for yourself for your paste. When I evaluate solder pastes I require good tack, no solder balls, and proper wetting after 4 hours at "reasonable" ambient conditions. I also print boards and put them in a temp/humidity ch
Electronics Forum | Fri Mar 21 11:10:24 EST 2003 | davef
There is no standard. If your boards solder well, they're good. Well soldered boards that have been stored a long time will have field life similar to well soldered boards that have not been stored a long time. The solderability of boards depends
