"Stefan Trethan" <
stefan_trethan@...> writes:
> The problem with the hotplate is that it won't work on PCBs with
> SMDs on both sides, or will it?
It won't. It works well only because the hotplate heats the PCB
evenly (assuming you have even heat, or move the board around to heat
it evenly) and melts the paste before the parts get too hot. You can
even touch up some of the parts while the solder is liquid, if needed.
I do the more densly populated side on the hotplate, and the other
side manually. I still use paste and reflow, just not the hotplate.
My technique for the back side:
∗ Apply paste to the pcb using the syringe, manually.
∗ Place all components (sometimes I do all of one type at a time).
∗ For each part, hold it down with the tips of the tweezers or a
toothpick, and touch your iron to each end. That melts the paste
between the part and the board.
Usually I only have resistors and capacitors on the back, they're easy
to solder. The hotplate is most needed for QFNs, TQFPs, fine pitch
connectors, etc. I use 0.5mm pitch parts a lot these days.
Sometimes I use the talon for parts on the back. I can heat both ends
at the same time, move the part around with it if needed, and the
solder doesn't stick to the talon as much as it sticks to the iron.