Rad project from Kevin Hubbard at Black Mesa Labs documenting the tiny hot plate built for SMT reflow on small-sized PCBs, as in 1″ small. This hot plate therefore has a smaller footprint than most, and cools down significantly sooner than larger surface-area plates.
Black Mesa Labs has been using a $20 hot plate for a year now for soldering QFN ICs to PCBs using the BML Inverted Solder Ball reflow technique. This works great for soldering 0.5mm pitch QFN and LGA type packages that would otherwise require messy stencils and paste. Only issue so far has been the size ( 10″x10″x3″ ) and thermal mass of the commercial hot plate as it consumes precious microscope work area and unfortunately stays quite hot for 30+ minutes after a quick 4 minute single IC reflow job. BML boards are mostly 1″x1″, so a 800W hot plate with a 6″ diameter heating surface is overkill for most jobs.