Greetings:
What are the favored techniques for hand or manual application of solder paste to PCBs for attaching SMD devices down to 0603 and 0.5mm pitch ICs?
I had tried paste in the past only to be frustrated by the inability to deposit repeatable quantities of paste by hand with the syringe in which it came. Also the paste came out as "turds" which remained turd-shaped on the pads, and so when the part was stuck down, the paste would squeeze out from under the legs in an asymmetric fashion leading to a rather uneven distribution of solder.
Also there was quite a problem with solder balls left over after flowing the paste with an iron. I didn't try hot air, and am averse to manually applied hot air since it seems like a method which offers the poorest possible control of temperature. I could be wrong about this though, and would appreciate any valid argument to the contrary.
So I switched to 0.015" wire solder for all my SMD stuff, and developed an ability to assemble with that producing very repeatable joints looking little worse than factory work.
But I am rethinking paste, particularly considering the additional difficulty of soldering with Pb-free alloys.
I am aware that there are automated syringe applicator machines which can be set to deliver repeatable paste quantites. So this is a semi-manual approach. But such a machine is likely too expensive for my personal use.
What do you do?
Thanks for comments.
Good day!