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 | 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 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 | 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 | 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 | Fri Apr 04 01:39:21 EDT 2008 | slthomas
All of what Dave says is spot on. I suspect that the most likely corresponding defects on your assemblies would be poor wetting and insufficient solder.
Electronics Forum | Fri Apr 04 14:54:19 EDT 2008 | alexs
Thanks for the reply. Just one more question. If there is less solvent but the residues are harder to clean. would there be more contaminant left on the boards? Has anyone did a cleanliness test?
Electronics Forum | Mon Apr 07 22:20:31 EDT 2008 | davef
Yes you can, although we don't think it's a good idea. Look here: http://www.smtnet.com/forums/Index.cfm?CFApp=1&Message_ID=48159
Electronics Forum | Wed Dec 09 09:47:32 EST 2009 | dyoungquist
I am curious as to why you need to mix.... We use a 500g cartridge with air gun. Our process is remove the cartridge from the fridge, allow it to warm up to room temperature before inserting into air gun, then apply bead of paste to the stencil. N
Electronics Forum | Sat Dec 18 15:23:05 EST 2004 | grayman
We used to add flux on a "expired" solder paste but we discontinued as there are many problems and customers complaints coming from our American customer. Like unwetted solder pads,dull and cold solder and many others. The profit is really ok but qua
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