What can we add to the solder paste? - Electronic Circuits Projects Diagrams Free

Richard Principal · 24th May 2007, 09:10 AM

A week or more ago a PCB went though the solder machine, and for some strange reason the solder paste did not melt, now the paste has dried out, (we only just found out today) all the through-hole parts have been added (not me, say no more)

I noticed that when I tried to solder it with hot air that did not work, but if I use a tip of the soldering iron that works OK But it is a lot slower than hot air,

My question: can any chemical be added to the lead free paste so to sort of rejuvenate the paste?

justDIY · 24th May 2007, 12:30 PM

you could try globbing generous amounts of flux on, then putting it in an oven to pre-heat for a few min (go as high as your lowest rated part will allow) before starting in with the hot-air, but it sounds like the PCB is hosed.

did you use lead free paste, but had the machine set for standard solder (wrong temperature profile), or was the solder paste expired?

Richard Principal · 24th May 2007, 04:59 PM

no the real problem was the chain was dry and it jammed in the morning about 20 minutes after the oven was turning on, after the conveyor was manual turned off and back on the conveyor went fast when it was turned back on, so the board did not get the heat for the right time. the boards were checked but one must of got missed. flux was added, but that did not help. looks like a busy day with the soldering iron.

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24th May 2007, 09:10 AM	#1
Richard Principal	What can we add to the solder paste? A week or more ago a PCB went though the solder machine, and for some strange reason the solder paste did not melt, now the paste has dried out, (we only just found out today) all the through-hole parts have been added (not me, say no more) I noticed that when I tried to solder it with hot air that did not work, but if I use a tip of the soldering iron that works OK But it is a lot slower than hot air, My question: can any chemical be added to the lead free paste so to sort of rejuvenate the paste?

24th May 2007, 12:30 PM	#2
justDIY	you could try globbing generous amounts of flux on, then putting it in an oven to pre-heat for a few min (go as high as your lowest rated part will allow) before starting in with the hot-air, but it sounds like the PCB is hosed. did you use lead free paste, but had the machine set for standard solder (wrong temperature profile), or was the solder paste expired? __________________ If you don't have a planet, what good are gold bars? want to contact me directly? gmail gordonthree check out my project website: http://projects.dimension-x.net Favorite numbers: 09 F9 11 02 9D 74 E3 5B D8 41 56 C5 63 56 88 C0

24th May 2007, 04:59 PM	#3
Richard Principal	no the real problem was the chain was dry and it jammed in the morning about 20 minutes after the oven was turning on, after the conveyor was manual turned off and back on the conveyor went fast when it was turned back on, so the board did not get the heat for the right time. the boards were checked but one must of got missed. flux was added, but that did not help. looks like a busy day with the soldering iron.