Leaded paste has a higher process window than leadfree, so I would recommend that.
Use no-clean rather than water soluble. The fluxes in water soluble can be more problematic if not removed completely (which is difficult).
Shelf life is indeed limited, more so with some pastes than other. Refrigeration is recommended.
I have found that I like Amtech paste.
<
http://www.amtechsolder.com/pastes.html>
The reason is simple, it works as good as any and I can get it at Farnell (re-badged under the chipquick brand).
Unlike other pastes they carry it seems to be fresh (enough turnover) and doesn't require refrigerated shipping.
The syringes have more air bubbles than high end brands (such as Martin SMT), but the cheap price and cheap shipping make up for that.
ST
On Tue, Aug 19, 2014 at 12:16 AM,
qz9090@... [Homebrew_PCBs]
<Homebrew_PCBs@yahoogroups.com> wrote:
As I continue to assemble my SMT tools, supplies and processes, I was looking at acquiring some solder paste. Unfortunately, there are several kinds of solder paste? What are the pros and cons? Should I consider water soluble paste? Does the tin vs lead vs copper mixture have a significant impact on my selection?It looks like shelf-life is limited, should that be a factor in my selection?Any input on this matter would be greatly appreciated.Thanks.FP