[Moved] Can anyone recommend one solder paste for me?

[zsuhh]

hope it can be used in room temperature for a relatively longer peroid of time.

 

[milan.rajik]

What is the normal temperature at your place ?

 

[D.A.(Tony)Stewart]

solder paste needs to be sealed when not used and stored in a fridge for twice the life (1 yr)and ideally reflowed ASAP after printing for best results in a 50% controlled humidity environment to reduce dry time.

copper boards need to be plastic-wrap sealed from air until used to reduce oxidation.

Of course it needs to be well mixed and screen with clean tools.

If you haven't followed these requirements, your experience may be pooor for room temp exposure and solder reflow quality.


There are many types of solids and fluxes, lead-free can be Sn96.5Ag3.0Cu0.5 (216'C) or Sn42Bi58 (42/58) fluxes can be no-clean or water clean , which I prefer for reliability with humid dust to prevent corrosion.

But there is more physics in the study of the flow of deformed susbtance or Rheology.

"the rheological network has a more physical nature characterized by dipole forces, hydrogen bridges, electrostatic and/or Van der Waals forces."

In the end , the best solder paste might last 2 hrs with the controlled humidity and 6 to 8 months sealed at room temp when not used .

This decreases rapidly above 25'C room temp.

 

[zsuhh]

Thank you so much for so detail explanation.