I had made a version 3 of the VBI injector board some time ago, and had even made a first attempt at soldering it together. However, the AVR did not work and I already suspected that it was bad. I finally ordered a new one. It became time to solder it on and I decided to use the "hot plate/skillet" method.
This method is to basically apply some solder paste on the PCB, put the surface mount components on the solder paste, and then heat the entire bottom of the board on a skillet. Melting point of the solder paste is between 425-450F (I forget the C conversion).
Unfortunately, as I had already soldered on some (previously de-soldered) pin headers, the PCB could not get good contact with the skillet. I was hoping that by heating up the pins that the board would slide down once the solder on the pins heated up, and as you can see in the video, it does slide down, but not quite enough.
NOTE : almost all of these components have been desoldered from a previous board which is why they look charred. Only the AVR is new.
So the right side of the board gets hot enough but the left side does not. This means that half of the AVR pins are done.
I decided to use my newly acquired hot air gun to finish the job. As you can see, it worked quite nicely. I was able to finish the 10k resistor, the rest of the AVR, and the MUX IC.