[Joel_Mckay]

In general, most single-sided PCB work with 0.5mm pitch components can be done by hand with a metal stencil + dry-wall trowel edge, SAC305 Type T4 or T5 paste, hot-air rework hand tool, and or a toaster oven re-flow kit (will often smoke flux due to bad temperature profiles.)

Getting a PCB mostly factory assembled for you is likely the better choice if you live in a building, as dropping hundreds of 100nF MLCC on a project can be brutal.

I guess the answer is yes one can do prototypes by hand if you take design considerations for pad access (sloppy mechanical tolerance for pencil/air rework), but probably one should be spending their time on design for lab EMC/EMI. =3

Robert Feranec does quite a few EE interviews, factory tours, and is generally accurate 97% of the time.

https://www.youtube.com/@RobertFeranec/videos

[junon]

I know all of this; assembly of a $400 board usually has a MOQ of 5 off the top of my head, which for a board that is a prototype isn't feasible.

I know about how to do reflow. I'm asking about the population step after paste deposition.

[Joel_Mckay]

Could also keep your design tolerances less tight (QFN>BGA), and use a cheaper PCB fab house.

In general, for small discreet components they should be able to partially pre-fill the PCB for under $23/pc. The expensive/sensitive stuff you manually add later.

Air-tweezers and a magnifier also do work, but you will get a sore back pretty quickly.

There were a few manual-first exceptions I saw with fussy RF component selection (better s parameters if mounted upside-down), instrumentation grade high-precision components, pricey chips, and avoiding BGA x-ray pad inspection.

Setting up a small home PnP takes time, practice, and space. Not necessary if you just dropped on 5 chips using generic stencils, and re-flow. =3