I will just like to know if is ok to build a board with a BGA ,with water soluable paste and washed or is better to use a no clean paste . And one last question , what do you guys think about the better paste Kester or Indium .
It is okay to use OA flux if you have a very robust cleaning process. lots of water and saponafier are good things. No-Clean is much safer when it comes to reliability. I personally like the Indium no-clean products.