Solder will only go where there is enough heat to make it flow, flux does help solder flow but going someplace where you don't place the tip of the soldering iron it not going to happen.
just a dap will do just fine.
Update to thread can be found here:
http://cs.trains.com/mrr/f/744/t/281856.aspx
https://tstage9.wixsite.com/nyc-modeling
Time...It marches on...without ever turning around to see if anyone is even keeping in step.