Always use flux, even if everything is perfectly clean. It reduces the melt time and you're less likely to damage electronics or plastics.

I usually use flux; and after buying a bunch of chinese solder, I now only buy either MG Chem or Kester solder. It lasts so long, it's not worth the frustration over saving a few bucks...

Flux, flux, flux. All this talk about solder and flux... which flux is best?
I know I just switched to a different flux not too long ago.

If you're worried about the flux core going bad just store it in the freezer. Lasts forever just like beer.




Sean

Not sure about best but the MG Chemicals No-Clean flux pen works well and is convenient to use and store.

Ersa F-SW32 flux works awesome.

Forget the flux pen, you must use a paste style flux, any BGA flux works much better than a pen.

Paste is fine. I really like the liquid flux, though.

^This bad boy. I still haven't finished this lil' ass tin in like 4+ years.