Dear Kai,

I have to disagree with you Kai (a statement I do not make lightly given your experience). It most certainly is not impossible to solder the interconnections you describe by hand. I have personally soldered QFPs by hand. It does require a bit of technique, and it takes some time and patience, but it is not impossible.

Use a good magnigication lamp, and use the thinnest solder wire and the sharpest soldering tip you can find. I recommend using 63/37 Sn/Pb, no-clean or water-soluable if you simply cannot stand not cleaning your board. Start by pre-tinning the pads, and then removing the solder with a solder wick. If there is a trace between the pads, mask it with Kapton tape and an X-acto knife before you pre-tin. Next, pre-tin all of the leads on the part and clean them with solder wick. This will alleviate the absence of solder mask by producing a strong flow tendancy (surface tension) on the pre-tinned surfaces. Finally, position the component on the pads and lightly solder the end of a corner lead to the center of its pad. Next, tack the opposite corner in a similare fashion. These corners will hold the remaining pins in alignment while you lightly solder each one. Once the other pins are soldered go back and re-melt the solder on the first two pins. This will relieve any tension that may have been stored in the leads by torquing them to align the others. The only other trick is to be sure that you clean your soldering tip after each lead and use the least amount of solder on each lead that you can. I generally run my soldering tip at about 300 °C.