I actually came up with that idea a few days ago and it worked! My favorite technique that I 'invented' (though I'm sure it's been done before) goes as follows:
Paint the underside of the part with paste flux. Take a piece of solder wire and hammer it flat on a bench anvil until it's
extremely thin (almost like a stiff gold leaf). Put it in the flux under the part with tweezers so I don't contaminate with skin oils. Clip the part in place. Heat with a torch, and the solder melts and adheres. If it is slightly under-full I then flatten the wire and clip off tiny pieces and place them with tweezers then flow the solder where I want it. Does it take a while? Yes. It's much slower than I want it to be. But on the other hand the joints are pristine and clean up is almost non-existent. Aside from a brief wipe down and light buff to remove oxides there is very little tinning (if any at all) to address. There is little to no risk of damage from over heating or removing too much material while buffing away tinning.
But this is also extremely dependent on the fit of the part. So far my fitting skills have been truly excellent (if I do say so myself
) and very little solder is needed to fill and adhere in the first place.
I'm also practicing other methods, but that's my favorite so far.
