I'm looking for some recommendations for brands of solder paste - I am getting a new reflow oven, and Ive been having fiddly results soldering finer pitch parts lately, and I decided maybe I should also pick up some new solder paste too, as this stuff is getting a little old and I'm running low anyway.
Looking for a leaded, and a lead free (normal stuff, not that ultra-low-temp stuff for cellphone repair that is all over ebay) solder paste for assembling boards at home. No clean type.
The new reflow oven is going to be a T962-series one (not sure which size I'm going to go with yet) - it sounds like this works fine for both leaded and lead-free...
I apply paste through stainless steel stencil (I have a few plastic ones in circulation, but don't use them very often, and all the new ones are stainless), place parts using the ever-popular human pick and place...
I am now using 0.5mm pitch TQFP and QFN parts, and the cheapo paste I've been using just hasn't been meeting my needs.
I like smaller individual containers, as that helps keep my stock fresh while using it in smaller batches.
Solder paste dries out as the solvent evaporates, it has a limited lifetime, buying bulk is not a sensible option!
And before you think about buying bulk and storing it refridgerated, be aware that solvent vapours building up
inside a fridge or freezer can be a very serious explosion risk.
Thanks for the advise! I had a lot of recommendations for the Chip Quik brand (a few others recommended that one through other channels); So I've got a syringe of that coming from digikey (I got the T4 leaded - going unleaded will be for a future experiment for now, but my reading suggested that you should have T4 for 0.5mm pitch TQFP's, which I've been having trouble with)
larryd:
Have found that a wiped layer of liquid solder flux gives good results when using stencils and T3 paste.
I don't, because that also gets into the vias.
I do however sometimes add a bit (half a drop) of extra flux from a flux pen to a tub of (used) solder paste.
Workshop temp also has a big influence on the result. I add some IPA when it's a cold.
I look for the pasting/stencilling results. There should be nice well-defined raised blocks on the pads.
Not thin, not smudged. Sometimes impossible to get it 100% right.
Leo..
The key step is cleaning the pcb surface before stencilling (no fingerprints!). Squeegee pressure is important
for adhesion too - for hand use an old stainless stencil works very well for applying good pressure. A decent
stencil frame is vital for good results as the stencil must be under tension and flat on the pcb, otherwise paste
can seep between stencil and pcb.
Flat pads are important too, plated rather than hot-air-levelled makes a big difference for fine pad dimensions.
) bottle ~30 years old, add IPA to thin if needed.
