Few months ago I was informed that there is another way to solder PCB, much faster way. Before that I didn't know that there is difference between soldering paste and flux or that such things as a PCB stencils exists. To tell you the truth I was completely unaware that there are some other methods of soldering than regular one. On the video below is my first attempt to solder PCB using stencil done yesterday.
Tools & Parts used: PCB
Soldering paste (Sn63/Pb37)
Solder paste spreader
IRDA soldering station
Selecting stencil: After reading a lot about various stencils I have decided to order each and every version that's available, also considered doing homemade version but eventually that was removed as an option because PCB is way too complex. So basically you can order stainless steel or stencil based on polyimide films (mylar or kapton). In the table below you can see my impressions regarding each of them.
~100Eur, in some cases more
Medium, stencil is not so flexible
Medium, one stencil can be used for building about 200 PCB
My vote goes definitely for polyimide film based stencils. Not just because the price is lower but because it is really tricky to apply soldering paste on stainless steel stencil where FPGA should be placed. Because low flexibility you will end up with too much paste there once you remove stencil. With polyimide stencils that is not the case. They bend nicely under solder paste spreader so you will have proper quantity of paste placed on components pads each and every time.
Soldering: Only important thing here is temperature profile you must follow if you don't want to destroy components. Each manufacturer states maximum temperature values that we can't exceed. What we need is temperature values who will solder component and not overheat it and that's something done over defined period of time. Also In each component we can find moisture so if we heat component too much or too fast component will crack. This is temperature profile I m using.