Most of my electronic construction is SMD (surface mount). Usually a soldering iron is sufficient for the job, but when it isn't I have used a contract manufacturer to fit the fine parts. However with my relocation there is no longer someone handy to help. The solution is to use solder paste. This is dispensed from a sringe. To reflow it I preheat the PCB on a hotplate, and use a small hot air gun (as used for craft work for embossing).
The hot plate was home built using a cheap clothes iron: