Electronics Forum | Thu Apr 03 22:56:48 EDT 2008 | davef
Potential impacts of using expired solder paste are [University of Bolton]: * Changed paste rheology. Result: poor print quality * Loss of solvents. Result: reduced flux activity * Changed flux formulation. Result: More difficult to clean flux residu
Electronics Forum | Fri Apr 04 14:49:51 EDT 2008 | tombstone
Flux seperation is a common problem observed due to expiration of paste. The symptom is a yellow layer of flux when you open the jar. Excess flux separation will cause priting problems such as smearing and slumping.
Electronics Forum | Thu Apr 03 17:25:49 EDT 2008 | alexs
Hi All, I have some question about expired solder paste. What would be some of the effects regarding assembly quality. Is there any changes in flux composition toward the end of shelf life? Thanks in advance for any replies.
Electronics Forum | Mon Apr 07 19:12:13 EDT 2008 | kircchoffs
can we use the expired solder paste and put in a solder pot of wave machine?
Electronics Forum | Fri Apr 04 08:49:45 EDT 2008 | ck_the_flip
Define "expired" though... 1 week? 6 weeks? 1 month? 6 months? Unrefrigerated life is generally 30 days. If paste has been stored refrigerated at manufacturer recommended temperatures, what would you guys do, like say, if you owned your own shop
Electronics Forum | Tue Jan 08 17:29:20 EST 2002 | davef
Your research is on track. NC flux needs to reach activation temperature. Also, do not depend on the corrosion characteristics associated with the flux classification (ie, L1, L0, M1, M0, etc.), until the flux is activated by exposure to soldering
Electronics Forum | Mon Jan 07 21:07:00 EST 2002 | davef
Using a flux pen sounds like a good idea. Comments are: * I assume you�re talking aqueous flux. If not, some NC flux pens leave white residues. Nearly all of 15 samples suffered to varying degrees with white residues. * Use the same flux that you
Electronics Forum | Tue Jan 08 11:28:30 EST 2002 | mregalia
We use NC flux exclusively for SMT and wave soldering. And it is a fairly old formula from Multicore, though we are currently qualifying a new formula. The automated soldering does not appear to be a problem. It is only the hand soldering that causes
Electronics Forum | Mon Jan 07 13:06:16 EST 2002 | mregalia
My company has been doing its hand soldering using drip bottles for application of no-clean flux. This has created quite a few problems, especially on our microwave boards. I want to convert us over to flux pens. Does anyone have any suggestions or c
Electronics Forum | Tue Sep 21 13:10:10 EDT 1999 | Dave F
| Dear All, | | In order to understand the soldering technologies in SMT, I'd like to understand why some cards are soldered and then cleaned, or only soldered whitout water cleaning nor "ultra sound" wavelength. | | I mean that I wonder why we use
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