I saw something unexplainable while soldering

[Jarfi]

I am looking for physical explanations for an event I observed.

I am a beginner in soldering, bought some chapo solder iron, random solder tip and a soldering material with "Sn", "Pb" and "Cu" it seems. It's called "Elektronik Löndraht".

Now, when I was soldering tiny 2mm spaced circuit connectors, I noticed a strange thing, one of the silver colored metal balls next to the one I was soldering turned white goldish. It was a strange color, I touched it with the tip which is needle shaped and suddenly the "white layer" turned into smoke and dissipated.

It seems that fumes from soldering, accumulated and were attracted to the previously hot metal peral(maybe 1mm diameter) next to the one I was soldering.

I actually saw this happen, It just happened this one time and I have not been able to replicate the event.

Has anyone here ever experienced a similar thing, what exactly was I observing? Why would toxic fumes be attracted to and form a layer around a hot but solid metal pearl?

 

[christopher.s]

There is most likely a flux core in your solder. Flux helps the solder to flow on the parts being soldered. When it is heated, it vaporizes. Some of the flux condenses on the cooler solder pad.